Revision as of 09:29, 8 November 2016 view sourceLadislav Mecir (talk | contribs)Extended confirmed users11,014 editsm the link was used before← Previous edit | Latest revision as of 18:50, 19 January 2025 view source Gjb0zWxOb (talk | contribs)Extended confirmed users5,254 edits →2013–2014: First regulatory actions: improved phrasingTag: Visual edit | ||
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{{Short description|Decentralized digital currency}} | |||
{{Use dmy dates|date=February 2016}} | |||
{{for|the colloquial expression for coinage|Bit (money)}} | |||
{{Infobox currency | |||
{{Redirect-distinguish-text|₿|"฿" for ]}} | |||
| image_1 = Bitcoin logo.svg | |||
{{pp-extended|small=yes}} | |||
| image_title_1 = Prevailing bitcoin logo | |||
{{Use dmy dates|date=March 2024}} | |||
| issuing_authority = ]<ref name="JSC" /><ref name="tcdecentralized">{{cite news|last1=Empson|first1=Rip|title=Bitcoin: How An Unregulated, Decentralized Virtual Currency Just Became A Billion Dollar Market|url=https://techcrunch.com/2013/03/28/bitcoin-how-an-unregulated-decentralized-virtual-currency-just-became-a-billion-dollar-market/|accessdate=8 October 2016|work=TechCrunch|publisher=AOL inc.|date=28 March 2013}}</ref> | |||
{{Use American English|date=December 2017}} | |||
| issuing_authority_title = Administration | |||
{{infobox cryptocurrency | |||
| date_of_introduction = {{Start date and age|df=yes|2009|1|3}} | |||
| currency_name = Bitcoin | |||
| using_countries = Worldwide | |||
| image_1 = Bitcoin.svg | |||
| inflation_title = ] | |||
| image_2 = | |||
| inflation_rate = 12.5 bitcoins per block (approximately every ten minutes) until mid 2020,<ref name=quantitative>{{cite web |title=Quantitative Analysis of the Full Bitcoin Transaction Graph |url=http://eprint.iacr.org/2012/584.pdf |publisher=Cryptology ePrint Archive |accessdate=18 October 2012 |author=Ron Dorit |author2=Adi Shamir |year=2012}}</ref> and then afterwards 6.25 bitcoins per block for 4 years until next halving. This halving continues until 2110–40, when 21 million bitcoins will have been issued. | |||
| image_width_1 = 150 | |||
| inflation_source_date = | |||
| image_width_2 = 110 | |||
| subunit_ratio_3 = {{val|e=-8}} | |||
| image_title_1 = Official logo from bitcoin.org | |||
| subunit_name_3 = satoshi<ref name="satoshi unit">{{cite web |title=Cracking the Bitcoin: Digging Into a $131M USD Virtual Currency |url=http://www.dailytech.com/Cracking+the+Bitcoin+Digging+Into+a+131M+USD+Virtual+Currency/article21878.htm |author=Jason Mick |publisher=Daily Tech |date=12 June 2011 |accessdate=30 September 2012 |deadurl=no}}</ref> <!-- "nano" is not currently possible because the smallest amount of possible Bitcoin is 0.00000001, which would be 10 "nanobitcoins". A new name was invented called "satoshi" and is used in many of this article's sources. Please see the article called "Nano-" and note that a "nano" anything is a billionth (10^-9). --> | |||
| alt1 = Prevailing bitcoin logo | |||
| subunit_ratio_2 = {{val|e=-6}} | |||
| precision = 10<sup>−8</sup> | |||
| subunit_name_2 = microbitcoin, bit<ref name="bits unit">{{cite web |title=BitPay, Bitcoin, and where to put that decimal point |url=https://blog.bitpay.com/bitpay-bitcoin-and-where-to-put-that-decimal-point/ |last=Garzik |first=Jeff |date=2 May 2014 |accessdate=20 November 2015}}</ref> | |||
| subunit_ratio_1 = {{frac|1000}} | |||
| symbol_subunit_2 = μBTC | |||
| subunit_name_1 = Millibitcoin | |||
| subunit_ratio_1 = {{val|e=-3}} | |||
| subunit_ratio_2 = {{frac|{{val|1000000}}}} | |||
| subunit_name_1 = millibitcoin | |||
| subunit_name_2 = Microbitcoin | |||
| symbol_subunit_1 = mBTC | |||
| subunit_ratio_3 = {{frac|{{val|100000000}}}} | |||
| symbol = BTC,{{refn | group = note | name = BTCcode | {{as of | 2014}}, BTC is a commonly used code.<ref name="standardize">{{cite web |publisher=] |author=Nermin Hajdarbegovic |date=7 October 2014 |accessdate=28 January 2015 |title=Bitcoin Foundation to Standardise Bitcoin Symbol and Code Next Year |url=http://www.coindesk.com/bitcoin-foundation-standardise-bitcoin-symbol-code-next-year/}}</ref> It does not conform to ] as BT is the country code of Bhutan.}} XBT,{{refn | group = note | name = XBTcode | {{as of | 2014}}, XBT, a code that conforms to ISO 4217 though is not officially part of it, is used by ],<ref>{{cite news |title=Bitcoin Ticker Available On Bloomberg Terminal For Employees |publisher=] |url=http://techcrunch.com/2013/08/09/bitcoin-ticker-available-on-bloomberg-terminal/ |date=9 August 2013 |author=Romain Dillet |accessdate=2 November 2014}}</ref> ],<ref>{{cite news |title=Bitcoin Composite Quote (XBT) |url=http://money.cnn.com/quote/quote.html?symb=XBT |publisher=CNN |work=CNN Money |accessdate=2 November 2014}}</ref> and ].<ref>{{cite web |title=XBT – Bitcoin |publisher=xe.com |accessdate=2 November 2014 |url=http://www.xe.com/currency/xbt-bitcoin?}}</ref>}} {{nowrap|]}}, {{refn | group = note | name = BTCsym | The proposal for the addition of bitcoin sign {{nowrap|]}} has been accepted by ].<ref name="shirriff" />}} Ƀ<ref name=cd0409>{{cite news |url=http://www.coindesk.com/industry-website-advocate-bitcoins-unicode-symbol/ |title=Industry group aims to change bitcoin symbol to ‘Ƀ’ |first=Daniel |last=Cawrey |date=2014-04-09 |work=CoinDesk}}</ref> | |||
| subunit_name_3 = {{lang|ja-Latn|Satoshi|italic=no}}{{efn|name=satoshi}}<ref name="satoshi unit">{{Cite journal |last=Bradbury |first=Danny |date=November 2013 |title=The problem with Bitcoin |url=https://linkinghub.elsevier.com/retrieve/pii/S1361372313701015 |journal=Computer Fraud & Security |language=en |volume=2013 |issue=11 |pages=5–8 |doi=10.1016/S1361-3723(13)70101-5 |access-date=25 November 2023 |archive-date=18 January 2023 |archive-url=https://web.archive.org/web/20230118052355/https://linkinghub.elsevier.com/retrieve/pii/S1361372313701015 |url-status=live |issn=1361-3723}}</ref> | |||
| used_coins = Unspent outputs of transactions denominated in any multiple of satoshis{{r|"Antonopoulos2014"|page=ch. 5}} | |||
| plural = Bitcoins | |||
| symbol = '''₿'''<br/>(Unicode: {{unichar|20BF|BITCOIN SIGN|html=}})<ref name="unicode-10">{{cite web |date=20 June 2017 |title=Unicode 10.0.0 |url=https://www.unicode.org/versions/Unicode10.0.0/ |url-status=live |archive-url=https://web.archive.org/web/20170620130342/http://www.unicode.org/versions/Unicode10.0.0/ |archive-date=20 June 2017 |access-date=20 June 2017 |publisher=Unicode Consortium}}</ref> | |||
| code = BTC | |||
| implementations = ] | |||
| initial_release_version = 0.1.0 | |||
| initial_release_date = {{Start date and age|df=yes|2009|1|9|p=y}} | |||
| code_repository = {{URL|https://github.com/bitcoin/bitcoin}} | |||
| status = Active | |||
| latest_release_version = 28.0 | |||
| latest_release_date = {{Start date and age|df=yes|2024|10|04|p=y}}<ref>{{cite web |title=Bitcoin Core 28.0 released |date=2 October 2024 |url=https://bitcoincore.org/en/2024/10/02/release-28.0/ |access-date=5 October 2024 |archive-date=5 October 2024 |archive-url=https://web.archive.org/web/20241005063435/https://bitcoincore.org/en/2024/10/02/release-28.0/ |url-status=live}}</ref> | |||
| forked_from = | |||
| website = {{URL|https://bitcoin.org}} | |||
| programming_languages = C++ | |||
| operating_system = | |||
| author = ] | |||
| developer = | |||
| white_paper = | |||
| source_model = ] | |||
| license = ] | |||
| ledger_start = {{Start date and age|df=yes|2009|1|3|p=y}} | |||
| hash_function = ] (two rounds) | |||
| circulating_supply = ₿19,591,231 ({{as of|2024|01|06|lc=y}}) | |||
| supply_limit = ₿21,000,000{{efn|name=supply}} | |||
| timestamping = ] (partial hash inversion) | |||
| issuance_schedule = Decentralized (block reward)<br />Initially ₿50 per block, halved every 210,000 blocks | |||
| block_time = 10 minutes | |||
| block_reward = ₿3.125 ({{as of|2024|lc=y}}) | |||
| exchange_rate = Floating | |||
| market_cap = <!--A reliable source is required --> | |||
| using_countries = ]<ref name="BTCSVSept7FT">{{cite news |title=El Salvador's dangerous gamble on bitcoin |url=https://www.ft.com/content/c257a925-c864-4495-9149-d8956d786310 |date=7 September 2021 |access-date=7 September 2021 |work=] |department=The editorial board |archive-date=7 September 2021 |archive-url=https://web.archive.org/web/20210907081627/https://www.ft.com/content/c257a925-c864-4495-9149-d8956d786310 |url-status=live }}</ref> | |||
}} | }} | ||
{{Special characters}} | {{Special characters}} | ||
'''Bitcoin''' (abbreviation: '''BTC'''; ]: '''₿''') is the first ] ]. Based on a ] ideology, bitcoin was invented in 2008 by ], an unknown person.<ref name="whoissn">{{Cite news |last=S. |first=L. |date=2 November 2015 |title=Who is Satoshi Nakamoto? |newspaper=The Economist |url=https://www.economist.com/the-economist-explains/2015/11/02/who-is-satoshi-nakamoto |access-date=21 November 2023 |archive-date=22 November 2020 |archive-url=https://web.archive.org/web/20201122172929/https://www.economist.com/the-economist-explains/2015/11/02/who-is-satoshi-nakamoto |url-status=live }}</ref> Use of bitcoin as a ] began in 2009,<ref name="NY2011">{{Cite magazine |last=Davis |first=Joshua |date=10 October 2011 |title=The Crypto-Currency: Bitcoin and its mysterious inventor |url=https://www.newyorker.com/magazine/2011/10/10/the-crypto-currency |url-status=live |archive-url=https://web.archive.org/web/20141101014157/http://www.newyorker.com/magazine/2011/10/10/the-crypto-currency |archive-date=1 November 2014 |access-date=31 October 2014 |magazine=]}}</ref> with the release of its ].<ref name="Antonopoulos2014">{{Cite book |last=Antonopoulos |first=Andreas M. |title=Mastering Bitcoin: Unlocking Digital Crypto-Currencies |year=2014 |publisher=O'Reilly Media |isbn=978-1-4493-7404-4 |author-link=Andreas Antonopoulos}}</ref>{{rp|ch. 1}} In 2021, ].<ref name="BTCSVSept7FT" /> It is mostly seen as an ] and has been described by some scholars as an ].<ref name="4Nobels">{{Cite news |last=Wolff-Mann |first=Ethan |date=27 April 2018 |title='Only good for drug dealers': More Nobel prize winners snub bitcoin |work=Yahoo Finance |url=https://finance.yahoo.com/news/good-drug-dealers-nobel-prize-winners-snub-bitcoin-184903784.html |url-status=live |access-date=7 June 2018 |archive-url=https://web.archive.org/web/20180612141128/https://finance.yahoo.com/news/good-drug-dealers-nobel-prize-winners-snub-bitcoin-184903784.html |archive-date=12 June 2018}}</ref> As bitcoin is ]ous, ] has attracted the attention of regulators, leading to ] {{as of|2021|lc=yes}}.<ref name="SunYin2019">{{Cite journal |last1=Sun Yin |first1=Hao Hua |last2=Langenheldt |first2=Klaus |last3=Harlev |first3=Mikkel |last4=Mukkamala |first4=Raghava Rao |last5=Vatrapu |first5=Ravi |date=2 January 2019 |title=Regulating Cryptocurrencies: A Supervised Machine Learning Approach to De-Anonymizing the Bitcoin Blockchain |url=https://www.researchgate.net/publication/332118587 |journal=] |language=en |volume=36 |issue=1 |page=65 |doi=10.1080/07421222.2018.1550550 |s2cid=132398387 |issn=0742-1222 |access-date=29 November 2023 |archive-date=21 April 2024 |archive-url=https://web.archive.org/web/20240421113631/https://www.researchgate.net/publication/332118587_Regulating_Cryptocurrencies_A_Supervised_Machine_Learning_Approach_to_De-Anonymizing_the_Bitcoin_Blockchain |url-status=live }}</ref> | |||
'''Bitcoin''' is a ] and a ]{{r|primer|p=3}} invented{{r|primer|p=3,4}}{{r|NY2011}} by an unidentified programmer, or group of programmers,{{r|dh150613}} under the name of ].<ref name="whoissn">{{cite news|last1=S.|first1=L.|title=Who is Satoshi Nakamoto?|url=http://www.economist.com/blogs/economist-explains/2015/11/economist-explains-1|accessdate=23 September 2016|work=The Economist|publisher=The Economist Newspaper Limited|date=2 November 2015}}</ref> Bitcoin was introduced on 31 October 2008 to a cryptography mailing list,<ref name="ageofcr">{{cite book |last1=Vigna |first1=Paul |last2=Casey |first2=Michael J. |title=The Age of Cryptocurrency: How Bitcoin and Digital Money Are Challenging the Global Economic Order |date=January 2015 |publisher=St. Martin's Press |location=New York |isbn=978-1-250-06563-6 |edition=1}}</ref> and released as ] in 2009.<ref name="NY2011">{{cite web |last=Davis |first=Joshua |title=The Crypto-Currency: Bitcoin and its mysterious inventor |url=http://www.newyorker.com/reporting/2011/10/10/111010fa_fact_davis |work=The New Yorker |date=10 October 2011 |accessdate=31 October 2014}}</ref> There have been various claims and speculation concerning the identity of Nakamoto, none of which are confirmed.{{r|whoissn}} | |||
The system is ] and transactions take place between users directly, without an intermediary.<ref name="primer" />{{rp|4}} These transactions are verified by network ] and recorded in a public ] called the ''blockchain'',{{r|kopstein}} which uses bitcoin as its ]. Since the system works without a central repository or single administrator, the ] categorizes bitcoin as a decentralized ].<ref name="JSC">{{cite web |url=https://www.fincen.gov/sites/default/files/2016-08/20131118.pdf |title=Statement of Jennifer Shasky Calvery, Director Financial Crimes Enforcement Network United States Department of the Treasury Before the United States Senate Committee on Banking, Housing, and Urban Affairs Subcommittee on National Security and International Trade and Finance Subcommittee on Economic Policy |publisher=Financial Crimes Enforcement Network |work=fincen.gov |date=19 November 2013 |accessdate=1 June 2014}}</ref> Bitcoin is often called the first cryptocurrency,<ref name="f_c1">{{cite web |url=http://www.scmp.com/news/world/article/1482245/drug-market-moving-quickly-online-global-user-survey-finds |title=Drug market moving quickly online, global user survey finds |publisher=South China Morning Post Publishers |work=South China Morning Post |date=14 April 2014 |accessdate=7 January 2015}}</ref><ref name="f_c2">{{cite news |url=http://www.telegraph.co.uk/technology/news/10881213/The-coming-digital-anarchy.html |title=The coming digital anarchy |publisher=Telegraph Media Group Limited |work=The Telegraph |date=9 June 2014 |accessdate=7 January 2015 |author=Sparkes, Matthew |location=London}}</ref><ref name="f_c3">{{cite web |first=Kim |last=Lachance Shandrow |url=http://www.entrepreneur.com/article/234340 |title=This Company Is Now the Largest in the World to Accept Bitcoin |publisher=Entrepreneur Media, Inc |work=entrepreneur.com |date=30 May 2014 |accessdate=7 January 2015}}</ref> although prior systems existed{{refn|group=note|name=prior|] was first used for a transaction in 1994,<ref>{{cite web |title=World's first electronic cash payment over computer networks. |publisher=Electronic Frontier Foundation |date=26 May 1994 |url=https://w2.eff.org/Privacy/Digital_money/?f=digicash.announce.txt |accessdate=20 November 2015}}</ref><ref>{{cite book |last1=Greenberg |first1=Andy |title=This Machine Kills Secrets: How WikiLeakers, Hacktivists, and Cypherpunks Are Freeing the World's Information |date=2012 |publisher=Ebury Publishing |isbn=978-0-7535-4801-1}}</ref> and OpenCoin, now known as ], had code written prior to November 2008.<ref>{{cite web |url=https://github.com/OpenCoin/opencoin-historic/commit/ecde30f6f5c00e4bf0381ee4df8cfbd3eba5552f |title=OpenCoin/opencoin-historic |publisher=GitHub, Inc. |work=github.com |accessdate=8 May 2015}}</ref>}} and it is more correctly described as the first decentralized ].<ref name="primer" /><ref name="Reuters101">{{cite web |url=http://www.trssllc.com/wp-content/uploads/2013/05/White_Paper_Bitcoin_101.pdf |title=Bitcoin 101 white paper |website= |publisher=Thomson Reuters |last=Sagona-Stophel |first=Katherine |accessdate=20 November 2015}}</ref> Bitcoin is the largest of its kind in terms of total market value.<ref name="WsjVolatile">{{cite news |last=Espinoza |first=Javier |title=Is It Time to Invest in Bitcoin? Cryptocurrencies Are Highly Volatile, but Some Say They Are Worth It |date=22 September 2014 |url=http://online.wsj.com/articles/how-to-decipher-cryptocurrencies-1411333011 |work=Journal Reports |publisher=The Wall Street Journal |accessdate=28 June 2016}}</ref> | |||
] in the ] ] verify transactions through ] and record them in a public ], called a ], without central oversight. ] between nodes is achieved using a computationally intensive process based on ], called ], that secures the bitcoin blockchain. Mining consumes large quantities of electricity and has been criticized for ].<ref>{{Cite news |last1=Huang |first1=Jon |last2=O’Neill |first2=Claire |last3=Tabuchi |first3=Hiroko |author3-link=Hiroko Tabuchi |date=3 September 2021 |title=Bitcoin Uses More Electricity Than Many Countries. How Is That Possible? |url=https://www.nytimes.com/interactive/2021/09/03/climate/bitcoin-carbon-footprint-electricity.html |url-status=live |archive-url=https://web.archive.org/web/20230217105559/https://www.nytimes.com/interactive/2021/09/03/climate/bitcoin-carbon-footprint-electricity.html |archive-date=17 February 2023 |access-date=26 October 2022 |work=The New York Times |language=en-US |issn=0362-4331}}</ref> | |||
Bitcoins are created as a reward in a competition in which users offer their computing power to verify and record bitcoin transactions into the blockchain. This activity is referred to as ''mining'' and successful miners are rewarded with transaction fees and newly created bitcoins.<ref name="primer">{{cite web |url=http://mercatus.org/sites/default/files/Brito_BitcoinPrimer.pdf |title=Bitcoin: A Primer for Policymakers |publisher=George Mason University |work=Mercatus Center |year=2013 |accessdate=22 October 2013 |author1=Jerry Brito |author2=Andrea Castillo |lastauthoramp=yes}}</ref> Besides being obtained by mining, bitcoins can be exchanged for other currencies,<ref>{{cite news |title=What is Bitcoin? |url=http://money.cnn.com/infographic/technology/what-is-bitcoin/ |publisher=CNN Money |accessdate=16 November 2015}}</ref> products, and services.<ref name="bitpay130916">{{cite web |url=http://techcrunch.com/2013/09/16/bitpay-10000-merchants/ |title=BitPay Passes 10,000 Bitcoin-Accepting Merchants On Its Payment Processing Network |author=Natasha Lomas |publisher=Techcrunch.com |work=Techcrunch |date=16 September 2013 |accessdate=21 October 2013}}</ref> When sending bitcoins, users can pay an optional transaction fee to the miners.<ref name="EconOfBTC">{{cite web |url=http://www.econinfosec.org/archive/weis2013/papers/KrollDaveyFeltenWEIS2013.pdf |title=The Economics of Bitcoin Mining, or Bitcoin in the Presence of Adversaries |work=The Twelfth Workshop on the Economics of Information Security (WEIS 2013) |date=11–12 June 2013 |accessdate=26 April 2016 |author1=Joshua A. Kroll |author2=Ian C. Davey |author3=Edward W. Felten |quote=A transaction fee is like a tip or gratuity left for the miner.}}</ref> This may expedite the transaction being confirmed. | |||
{{TOC LIMIT|4}} | |||
In February 2015, the number of merchants accepting bitcoin for products and services passed 100,000.<ref name=100tmerchants /> Instead of 2{{ndash}}3% typically imposed by ] processors, merchants accepting bitcoins often pay fees in the range from 0% to less than 2%.<ref name="merchantfee">{{cite news |url=http://www.nytimes.com/2013/10/31/technology/bitcoin-pursues-the-mainstream.html |title=Bitcoin Pursues the Mainstream |work=The New York Times |date=30 October 2013 |accessdate=4 November 2013 |author=Wingfield, Nick}}</ref> Despite the fourfold increase in the number of merchants accepting bitcoin in 2014, the cryptocurrency did not have much momentum in retail transactions.<ref name="MIT Technology Review">{{cite news |last=Orcutt |first=Mike |title=Is Bitcoin Stalling? |url=http://www.technologyreview.com/news/535221/is-bitcoin-stalling/ |accessdate=20 February 2015 |newspaper=MIT Technology Review |date=18 February 2015}}</ref> The ]<ref name="ebawarn" /> and other sources<ref name="primer" />{{rp|11}} have warned that bitcoin users are not protected by refund rights or ]s. The use of bitcoin by criminals has attracted the attention of financial regulators,<ref name="Lavin, Tim" /> legislative bodies,<ref name="USoff" /> law enforcement,<ref name="fbi_report" /> and media.<ref name="washp">{{cite news |url=http://articles.washingtonpost.com/2013-10-02/business/42613812_1_digital-currency-federal-authorities-reputation |title=Authorities shut down Silk Road, the world's largest Bitcoin-based drug market |work=The Washington Post |date=2 October 2013 |accessdate=21 October 2013 |author1=Timothy B. Lee |author2=Hayley Tsukayama |lastauthoramp=yes}}</ref> Criminal activities are primarily focused on ]s and theft, though officials in countries such as the United States also recognize that bitcoin can provide legitimate financial services.<ref name="USoff" /> | |||
==History== | |||
Journalist Nikolai Hampton characterized bitcoin as a form of digital money that uses several cryptographic techniques "to secure transactions between untrusted third parties, without the need for a central authority or bank."<ref name=cw20160905>{{cite news |last=Hampton|first=Nikolai |url=http://www.computerworld.com.au/article/606253/understanding-blockchain-hype-why-much-it-nothing-more-than-snake-oil-spin/ |title=Understanding the blockchain hype: Why much of it is nothing more than snake oil and spin |work=] |publisher=IDG |date=2016-09-05 |accessdate=2016-09-05 }}</ref> | |||
{{Main|History of bitcoin}} | |||
{{TOC limit|3}} | |||
===Background=== | |||
== Etymology and orthography == | |||
Before bitcoin, several ] were released, starting with ]'s ] in the 1980s.<ref name=Narayanan2017/> The idea that solutions to computational puzzles could have some value was first proposed by cryptographers ] and ] in 1992.<ref>{{Citation |last=Dwork |first=Cynthia |title=Pricing via Processing or Combatting Junk Mail |date=1993 |work=Advances in Cryptology — CRYPTO’ 92 |volume=740 |pages=139–147 |editor-last=Brickell |editor-first=Ernest F. |url=http://link.springer.com/10.1007/3-540-48071-4_10 |access-date=2025-01-02 |place=Berlin, Heidelberg |publisher=Springer Berlin Heidelberg |language=en |doi=10.1007/3-540-48071-4_10 |isbn=978-3-540-57340-1 |last2=Naor |first2=Moni}}</ref><ref name=Narayanan2017/> The concept was ] by ] who developed ], a ] scheme for ] in 1997.<ref name="Narayanan2017" /> The first proposals for distributed digital scarcity-based ] came from ]s ] (b-money) and ] (]) in 1998.<ref>{{Cite journal |last1=Tschorsch |first1=Florian |last2=Scheuermann |first2=Bjorn |date=2 March 2016 |title=Bitcoin and Beyond: A Technical Survey on Decentralized Digital Currencies |url=https://ieeexplore.ieee.org/document/7423672 |journal=IEEE Communications Surveys & Tutorials |volume=18 |issue=3 |pages=2084–2123 |doi=10.1109/COMST.2016.2535718 |s2cid=5115101 |issn=1553-877X |access-date=23 November 2023 |archive-date=19 November 2023 |archive-url=https://web.archive.org/web/20231119025114/http://ieeexplore.ieee.org/document/7423672 |url-status=live }}</ref> In 2004, ] developed the first currency based on reusable proof of work.<ref>{{cite book |last1=Judmayer |first1=Aljosha |chapter=History of Cryptographic Currencies |date=2017 |chapter-url=https://link.springer.com/10.1007/978-3-031-02352-1_3 |title=Blocks and Chains |pages=15–18 |publisher=] |language=en |doi=10.1007/978-3-031-02352-1_3 |isbn=978-3-031-01224-2 |last2=Stifter |first2=Nicholas |last3=Krombholz |first3=Katharina |last4=Weippl |first4=Edgar |series=Synthesis Lectures on Information Security, Privacy, and Trust |url=https://link.springer.com/book/10.1007/978-3-031-02352-1 |access-date=22 November 2023 |archive-date=22 November 2023 |archive-url=https://web.archive.org/web/20231122135006/https://link.springer.com/book/10.1007/978-3-031-02352-1 |url-status=live }}</ref> These various attempts were not successful:<ref name="Narayanan2017" /> Chaum's concept required centralized control and no banks wanted to sign on, Hashcash had no protection against ], while b-money and bit gold were not resistant to ]s.<ref name=Narayanan2017>{{Cite journal |last1=Narayanan |first1=Arvind |last2=Clark |first2=Jeremy |date=27 November 2017 |title=Bitcoin's academic pedigree |url=https://queue.acm.org/detail.cfm?id=3136559 |journal=] |volume=60 |issue=12 |pages=36–45 |doi=10.1145/3132259 |s2cid=6425116 |issn=0001-0782 |access-date=22 November 2023 |archive-date=14 October 2023 |archive-url=https://web.archive.org/web/20231014120907/https://queue.acm.org/detail.cfm?id=3136559 |url-status=live }}</ref> | |||
The word ''bitcoin'' occurred in the ] that defined bitcoin published in 2008. It is a ] of the words '']'' and ''coin''.{{r|btox}} The white paper frequently uses the shorter ''coin''.<ref name="paper">{{cite web |url=https://bitcoin.org/bitcoin.pdf |title=Bitcoin: A Peer-to-Peer Electronic Cash System |date=October 2008 |publisher=bitcoin.org |accessdate=28 April 2014 |first=Satoshi |last=Nakamoto}}</ref> | |||
===2008–2009: Creation=== | |||
There is no uniform convention for ''bitcoin'' capitalization. Some sources use ''Bitcoin'', capitalized, to refer to the technology and ] and ''bitcoin'', lowercase, to refer to the unit of account.<ref name="capitalization">{{cite web |url=http://www.newyorker.com/online/blogs/elements/2013/04/the-future-of-bitcoin.html |title=The Bitcoin Boom |publisher=Condé Nast |work=The New Yorker |date=2 April 2013 |accessdate=22 December 2013 |author=Bustillos, Maria |quote=Standards vary, but there seems to be a consensus forming around Bitcoin, capitalized, for the system, the software, and the network it runs on, and bitcoin, lowercase, for the currency itself.}}</ref> '']'',<ref>{{cite news |last=Vigna |first=Paul |title=BitBeat: Is It Bitcoin, or bitcoin? The Orthography of the Cryptography |url=http://blogs.wsj.com/moneybeat/2014/03/14/bitbeat-is-it-bitcoin-or-bitcoin-the-orthography-of-the-cryptography |accessdate=21 April 2014 |newspaper=] |date=3 March 2014}}</ref> '']'',<ref>{{cite web |publisher=The Chronicle of Higher Education (chronicle.com) |title=The latest style |date=14 April 2014 |last=Metcalf |first=Allan |series=Lingua Franca blog |url=http://chronicle.com/blogs/linguafranca/2014/04/11/the-latest-style/ |accessdate=19 April 2014}}</ref> and the '']''{{r|btox}} advocate use of lowercase ''bitcoin'' in all cases. This article follows the latter convention. | |||
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The domain name ''bitcoin.org'' was registered on 18 August 2008.<ref>{{Cite news |last=Bernard |first=Zoë |date=2 December 2017 |title=Everything you need to know about Bitcoin, its mysterious origins, and the many alleged identities of its creator |work=Business Insider |url=http://www.businessinsider.com/bitcoin-history-cryptocurrency-satoshi-nakamoto-2017-12 |url-status=live |access-date=15 June 2018 |archive-url=https://web.archive.org/web/20180615010015/http://www.businessinsider.com/bitcoin-history-cryptocurrency-satoshi-nakamoto-2017-12 |archive-date=15 June 2018}}</ref> On 31 October 2008, a link to a ] authored by ] titled ''Bitcoin: A Peer-to-Peer Electronic Cash System'' was posted to a cryptography mailing list.<ref>{{Cite news |last=Finley |first=Klint |date=31 October 2018 |title=After 10 Years, Bitcoin Has Changed Everything—And Nothing |magazine=Wired |url=https://www.wired.com/story/after-10-years-bitcoin-changed-everything-nothing/ |url-status=live |access-date=9 November 2018 |archive-url=https://web.archive.org/web/20181105070656/https://www.wired.com/story/after-10-years-bitcoin-changed-everything-nothing/ |archive-date=5 November 2018}}</ref> Nakamoto implemented the bitcoin software as ] and released it in January 2009.<ref name="NY2011" /> Nakamoto's identity remains unknown.{{r|whoissn}} According to computer scientist ], all individual components of bitcoin originated in earlier academic literature.<ref name=Narayanan2017/> Nakamoto's innovation was their complex interplay resulting in the first decentralized, ], ] tolerant digital cash system, that would eventually be referred to as the first blockchain.<ref name=Narayanan2017/><ref name="te20151031">{{Cite news |last=Economist Staff |date=31 October 2015 |title=Blockchains: The great chain of being sure about things |url=https://www.economist.com/news/briefing/21677228-technology-behind-bitcoin-lets-people-who-do-not-know-or-trust-each-other-build-dependable |url-status=live |newspaper=] |archive-url=https://web.archive.org/web/20160703000844/http://www.economist.com/news/briefing/21677228-technology-behind-bitcoin-lets-people-who-do-not-know-or-trust-each-other-build-dependable |archive-date=3 July 2016 |access-date=18 June 2016 }}</ref> Nakamoto's paper was not ]ed and was initially ignored by academics, who argued that it could not work.<ref name=Narayanan2017/> | |||
On 3 January 2009, the bitcoin network was created when Nakamoto mined the starting block of the chain, known as the '']''.<ref name="Wired:RFB">{{Cite magazine |last=Wallace, Benjamin |date=23 November 2011 |title=The Rise and Fall of Bitcoin |url=https://www.wired.com/2011/11/mf-bitcoin/ |url-status=live |magazine=Wired |archive-url=https://web.archive.org/web/20131031043919/http://www.wired.com/magazine/2011/11/mf_bitcoin |archive-date=31 October 2013 |access-date=13 October 2012}}</ref> Embedded in this block was the text "The Times 03/Jan/2009 Chancellor on brink of ]", which is the date and headline of an issue of '']'' newspaper.<ref name="NY2011" /> Nine days later, Hal Finney received the first bitcoin transaction: ten bitcoins from Nakamoto.<ref>{{Cite news |last=Popper |first=Nathaniel |date=30 August 2014 |title=Hal Finney, Cryptographer and Bitcoin Pioneer, Dies at 58 |work=] |url=https://www.nytimes.com/2014/08/31/business/hal-finney-cryptographer-and-bitcoin-pioneer-dies-at-58.html |url-status=live |access-date=2 September 2014 |archive-url=https://web.archive.org/web/20140903162835/http://www.nytimes.com/2014/08/31/business/hal-finney-cryptographer-and-bitcoin-pioneer-dies-at-58.html |archive-date=3 September 2014}}</ref> Wei Dai and Nick Szabo were also early supporters.<ref name="Wired:RFB" /> On May 22, 2010, the first known ] using bitcoin occurred when programmer Laszlo Hanyecz bought two ] pizzas for ₿10,000, in what would later be celebrated as "Bitcoin Pizza Day".<ref>{{cite news |last1=Cooper |first1=Anderson |title=Meet the man who spent millions worth of bitcoin on pizza |url=https://www.cbsnews.com/news/meet-the-man-who-spent-millions-worth-of-bitcoin-on-pizza-60-minutes-2019-05-16 |work=] |date=16 May 2019 |access-date=8 December 2021 |archive-date=8 December 2021 |archive-url=https://web.archive.org/web/20211208180706/https://www.cbsnews.com/news/meet-the-man-who-spent-millions-worth-of-bitcoin-on-pizza-60-minutes-2019-05-16/ |url-status=live }}</ref> | |||
== Design == | |||
=== |
===2010–2012: Early growth=== | ||
] estimate that Nakamoto had mined about one million bitcoins<ref>{{Cite news |last=McMillan |first=Robert |title=Who Owns the World's Biggest Bitcoin Wallet? The FBI |magazine=Wired |url=https://www.wired.com/2013/12/fbi-wallet/ |url-status=live |access-date=7 October 2016 |archive-url=https://web.archive.org/web/20161021221609/https://www.wired.com/2013/12/fbi-wallet/ |archive-date=21 October 2016}}</ref> before disappearing in 2010 when he handed the network alert key and control of the ] over to ]. Andresen later became lead developer at the ],<ref>{{cite news |last=Simonite |first=Tom |title=Meet Gavin Andresen, the most powerful person in the world of Bitcoin |date=15 August 2014 |url=https://www.technologyreview.com/2014/08/15/12784/the-man-who-really-built-bitcoin |work=] |access-date=22 November 2023 |archive-date=22 November 2023 |archive-url=https://web.archive.org/web/20231122163924/https://www.technologyreview.com/2014/08/15/12784/the-man-who-really-built-bitcoin |url-status=live }}</ref><ref>{{Cite news |last=Odell |first=Matt |date=21 September 2015 |title=A Solution To Bitcoin's Governance Problem |work=TechCrunch |url=https://techcrunch.com/2015/09/21/a-solution-to-bitcoins-governance-problem/ |url-status=live |access-date=24 January 2016 |archive-url=https://web.archive.org/web/20160126051521/http://techcrunch.com/2015/09/21/a-solution-to-bitcoins-governance-problem/ |archive-date=26 January 2016}}</ref> an ] founded in September 2012 to promote bitcoin.<ref>{{Cite news |last=Bustillos |first=Maria |date=1 April 2013 |title=The Bitcoin Boom |magazine=The New Yorker |url=https://www.newyorker.com/tech/elements/the-bitcoin-boom |url-status=live |access-date=30 July 2018 |archive-url=https://web.archive.org/web/20180702064450/https://www.newyorker.com/tech/elements/the-bitcoin-boom |archive-date=2 July 2018}}</ref> | |||
{{See also|Blockchain (database)}} | |||
The ''blockchain'' is a public ] that records bitcoin transactions.{{r|econbc}} A novel solution accomplishes this without any trusted central authority: maintenance of the blockchain is performed by a ] of communicating ] running bitcoin software.{{r|"primer"}} Transactions of the form ''payer X sends Y bitcoins to payee Z'' are ] to this network using readily available software applications.<ref>{{cite web |title=Bitcoin Wallet |url=http://www.investopedia.com/terms/b/bitcoin-wallet.asp?layout=infini&v=5A&orig=1&adtest=5A |publisher=Investopedia |accessdate=28 June 2016}}</ref> Network nodes can validate transactions, add them to their copy of the ledger, and then broadcast these ledger additions to other nodes. The blockchain is a ] – to achieve independent verification of the chain of ownership of any and every bitcoin (amount), each network node stores its own copy of the blockchain.<ref name="f_c2" /> Approximately six times per hour, a new group of accepted transactions, a block, is created, added to the blockchain, and quickly published to all nodes. This allows bitcoin software to determine when a particular bitcoin amount has been spent, which is necessary in order to prevent ] in an environment without central oversight. Whereas a conventional ledger records the transfers of actual ] or ]s that exist apart from it, the blockchain is the only place that bitcoins can be said to exist in the form of unspent outputs of transactions.<ref name="Antonopoulos2014" /> | |||
After early "]" transactions, the first major users of bitcoin were ]s, such as the ] ]. During its 30 months of existence, beginning in February 2011, Silk Road exclusively accepted bitcoins as payment, transacting ₿9.9 million, worth about $214 million.<ref name=JEP/>{{rp|222}} | |||
=== Units === | |||
The unit of account of the bitcoin system is bitcoin. {{As of|2014}}, symbols used to represent bitcoin are BTC,<ref group="note" name="BTCcode" /> XBT,<ref group="note" name="XBTcode" /> and {{nowrap|]}}.<ref group="note" name="BTCsym" /><ref name=btcregs>{{cite web |url=http://www.loc.gov/law/help/bitcoin-survey/regulation-of-bitcoin.pdf |title=Regulation of Bitcoin in Selected Jurisdictions |publisher=The Law Library of Congress, Global Legal Research Center |date=January 2014 |accessdate=26 August 2014}}</ref>{{rp|2}} Small amounts of bitcoin used as alternative units are millibitcoin (mBTC), microbitcoin (µBTC), and satoshi. Named in homage to bitcoin's creator, a ''satoshi'' is the smallest amount within bitcoin representing 0.00000001 bitcoin, one hundred millionth of a bitcoin.<ref name="satoshi unit" /> A ''millibitcoin'' equals to 0.001 bitcoin, one thousandth of bitcoin.<ref>{{cite news |url=http://edition.cnn.com/2014/06/18/business/bitcoin-your-way-to-a-double-espresso/ |title=Bitcoin your way to a double espresso |publisher=CNN |work=cnn.com |date=9 July 2014 |accessdate=23 April 2015 |author1=Katie Pisa |author2=Natasha Maguder |lastauthoramp=yes}}</ref> One ''microbitcoin'' equals to 0.000001 bitcoin, one millionth of a bitcoin. A microbitcoin is sometimes referred to as a ''bit''. | |||
===2013–2014: First regulatory actions=== | |||
A proposal was submitted to the ] in October 2015 to add a codepoint for the symbol.<ref name="shirriff">{{cite web |last1=Shirriff |first1=Ken |title=Proposal for addition of bitcoin sign |url=http://www.unicode.org/L2/L2015/15229-bitcoin-sign.pdf |website=unicode.org |publisher=] |accessdate=3 November 2015 |date=2 October 2015}}</ref> | |||
In March 2013, the US ] (FinCEN) established regulatory guidelines for "decentralized virtual currencies" such as bitcoin, classifying American bitcoin miners who sell their generated bitcoins as ]es, subject to registration and other legal obligations.<ref>{{cite news |last=Lee |first=Timothy B. |date=19 March 2013 |title=US regulator Bitcoin Exchanges Must Comply With Money Laundering Laws |url=https://arstechnica.com/tech-policy/2013/03/us-regulator-bitcoin-exchanges-must-comply-with-money-laundering-laws/ |url-status=live |archive-url=https://web.archive.org/web/20131021203745/http://arstechnica.com/tech-policy/2013/03/us-regulator-bitcoin-exchanges-must-comply-with-money-laundering-laws/ |archive-date=21 October 2013 |access-date=28 July 2017 |work=]}}</ref> In May 2013, US authorities seized the unregistered ] ].<ref>{{cite news |last=Dillet |first=Romain |title=Feds Seize Assets From Mt. Gox's Dwolla Account, Accuse It Of Violating Money Transfer Regulations |url=https://techcrunch.com/2013/05/16/mt-gox-dwolla-account-money-seizure/ |work=] |url-status=live |archive-url=https://web.archive.org/web/20131009161856/http://techcrunch.com/2013/05/16/mt-gox-dwolla-account-money-seizure/ |archive-date=9 October 2013 |access-date=15 May 2013}}</ref> In June 2013, the US ] seized ₿11.02 from an individual attempting to use them to purchase illicit drugs. This marked the first time a government agency had seized bitcoins.<ref>{{Cite news |last=Sampson |first=Tim |year=2013 |title=U.S. government makes its first-ever Bitcoin seizure |work=The Daily Dot |url=http://www.dailydot.com/business/11-bitcoins-seized-government-dea/ |url-status=live |access-date=15 October 2013 |archive-url=https://web.archive.org/web/20130712010826/http://www.dailydot.com/business/11-bitcoins-seized-government-dea/ |archive-date=12 July 2013}}</ref> The FBI seized about ₿30,000 in October 2013 from Silk Road, following the arrest of its founder ].<ref>{{Cite news |last=Hill |first=Kashmir |title=The FBI's Plan For The Millions Worth Of Bitcoins Seized From Silk Road |work=Forbes |url=https://www.forbes.com/sites/kashmirhill/2013/10/04/fbi-silk-road-bitcoin-seizure/ |url-status=live |archive-url=https://web.archive.org/web/20140502154935/http://www.forbes.com/sites/kashmirhill/2013/10/04/fbi-silk-road-bitcoin-seizure/ |archive-date=2 May 2014}}</ref> | |||
It is in the pipeline for position 20BF (₿) in the ] block. | |||
In December 2013, the ] prohibited Chinese financial institutions from using bitcoin.<ref>{{Cite news |last=Kelion, Leo |date=18 December 2013 |title=Bitcoin sinks after China restricts yuan exchanges |work=BBC News |url=https://www.bbc.co.uk/news/technology-25428866 |url-status=live |access-date=20 December 2013 |archive-url=https://web.archive.org/web/20131219214615/http://www.bbc.co.uk/news/technology-25428866 |archive-date=19 December 2013}}</ref> After the announcement, the value of bitcoin dropped,<ref>{{Cite news |date=6 December 2013 |title=China bans banks from bitcoin transactions |work=] |publisher=Reuters |url=https://www.smh.com.au/business/markets/currencies/china-bans-banks-from-bitcoin-transactions-20131206-2yugy.html |url-status=live |access-date=31 October 2014 |archive-url=https://web.archive.org/web/20140323102824/http://www.smh.com.au/business/markets/currencies/china-bans-banks-from-bitcoin-transactions-20131206-2yugy.html |archive-date=23 March 2014}}</ref> and ] no longer accepted bitcoins for certain services.<ref>{{Cite news |date=7 December 2013 |title=Baidu Stops Accepting Bitcoins After China Ban |work=Bloomberg |location=New York |url=https://www.bloomberg.com/news/2013-12-07/baidu-stops-accepting-bitcoins-after-china-ban.html |url-status=live |access-date=11 December 2013 |archive-url=https://web.archive.org/web/20131210214547/http://www.bloomberg.com/news/2013-12-07/baidu-stops-accepting-bitcoins-after-china-ban.html |archive-date=10 December 2013}}</ref> Buying real-world goods with any virtual currency had been illegal in China since at least 2009.<ref>{{cite web |date=29 June 2009 |title=China bars use of virtual money for trading in real goods |url=http://english.mofcom.gov.cn/aarticle/newsrelease/commonnews/200906/20090606364208.html |url-status=live |archive-url=https://web.archive.org/web/20131129184312/http://english.mofcom.gov.cn/aarticle/newsrelease/commonnews/200906/20090606364208.html |archive-date=29 November 2013 |access-date=10 January 2014 |publisher=English.mofcom.gov.cn}}</ref> | |||
=== Ownership === | |||
] | |||
===2015–2019=== | |||
Ownership of bitcoins implies that a user can spend bitcoins associated with a specific address. To do so, a payer must ] the transaction using the corresponding ]. Without knowledge of the private key, the transaction cannot be signed and bitcoins cannot be spent. The network verifies the signature using the ].<ref name="Antonopoulos2014" />{{rp|ch. 5}} | |||
Research produced by the ] estimated that in 2017, there were 2.9 to 5.8 million unique users using a ], most of them using bitcoin.<ref>{{cite web |last1=Hileman |first1=Garrick |last2=Rauchs |first2=Michel |title=Global Cryptocurrency Benchmarking Study |url=https://www.jbs.cam.ac.uk/fileadmin/user_upload/research/centres/alternative-finance/downloads/2017-global-cryptocurrency-benchmarking-study.pdf |url-status=live |archive-url=https://web.archive.org/web/20170410130007/https://www.jbs.cam.ac.uk/fileadmin/user_upload/research/centres/alternative-finance/downloads/2017-global-cryptocurrency-benchmarking-study.pdf |archive-date=10 April 2017 |access-date=14 April 2017 |publisher=Cambridge University}}</ref> In August 2017, the ] software upgrade was activated. Segwit was intended to support the ] as well as improve ].<ref>{{Cite news |last=Vigna |first=Paul |date=21 July 2017 |title=Bitcoin Rallies Sharply After Vote Resolves Bitter Scaling Debate |work=The Wall Street Journal |url=https://www.wsj.com/articles/bitcoin-rallies-sharply-after-vote-resolves-bitter-scaling-debate-1500656084 |access-date=21 November 2023 |archive-date=21 November 2023 |archive-url=https://web.archive.org/web/20231121164350/https://www.wsj.com/articles/bitcoin-rallies-sharply-after-vote-resolves-bitter-scaling-debate-1500656084 |url-status=live }}</ref> SegWit opponents, who supported larger blocks as a scalability solution, ] to create ], one of many ].<ref>{{Cite news |last=Selena Larson |date=1 August 2017 |title=Bitcoin split in two, here's what that means |work=CNN Tech |publisher=Cable News Network |url=https://money.cnn.com/2017/08/01/technology/business/bitcoin-cash-new-currency/index.html |url-status=live |access-date=2 April 2018 |archive-url=https://web.archive.org/web/20180227214042/https://money.cnn.com/2017/08/01/technology/business/bitcoin-cash-new-currency/index.html |archive-date=27 February 2018}}</ref> | |||
In December 2017, the first ] on bitcoin was introduced by the ] (CME).<ref>{{Cite web |url=https://www.cnbc.com/2017/12/17/worlds-largest-futures-exchange-set-to-launch-bitcoin-futures-sunday-night.html |title=Bitcoin debuts on the world's largest futures exchange, and prices fall slightly |date=17 December 2017 |access-date=19 January 2024 |website=CNBC |last=Cheng |first=Evelyn |archive-date=18 January 2024 |archive-url=https://web.archive.org/web/20240118182719/https://www.cnbc.com/2017/12/17/worlds-largest-futures-exchange-set-to-launch-bitcoin-futures-sunday-night.html |url-status=live }}</ref> | |||
If the private key is lost, the ] will not recognize any other evidence of ownership;<ref name="primer" /> the coins are then unusable, and thus effectively lost. For example, in 2013 one user claimed to have lost 7,500 bitcoins, worth $7.5 million at the time, when he accidentally discarded a hard drive containing his private key.<ref>{{cite news |title=Man Throws Away 7,500 Bitcoins, Now Worth $7.5 Million |date=29 November 2013 |url=http://washington.cbslocal.com/2013/11/29/man-throws-away-7500-bitcoins-now-worth-7-5-million/ |work=CBS DC |accessdate=23 January 2014}}</ref> | |||
In February 2018, the price crashed after China imposed a complete ban on bitcoin trading.<ref>{{Cite news |last=French |first=Sally |date=9 February 2017 |title=Here's proof that this bitcoin crash is far from the worst the cryptocurrency has seen |publisher=Market Watch |url=https://www.marketwatch.com/story/heres-proof-that-this-bitcoin-crash-is-far-from-the-worst-the-cryptocurrency-has-seen-2018-02-09 |url-status=live |access-date=3 July 2018 |archive-url=https://web.archive.org/web/20180703220246/https://www.marketwatch.com/story/heres-proof-that-this-bitcoin-crash-is-far-from-the-worst-the-cryptocurrency-has-seen-2018-02-09 |archive-date=3 July 2018}}</ref> The percentage of bitcoin trading in the Chinese ] fell from over 90% in September 2017 to less than 1% in June 2018.<ref>{{Cite news |date=7 July 2018 |title=RMB Bitcoin trading falls below 1 pct of world total |publisher=Xinhuanet |agency=] |url=http://www.xinhuanet.com/english/2018-07/07/c_137308879.htm |url-status=live |access-date=10 July 2018 |archive-url=https://web.archive.org/web/20180710225218/http://www.xinhuanet.com/english/2018-07/07/c_137308879.htm |archive-date=10 July 2018}}</ref> During the same year, bitcoin prices were negatively affected by several hacks or thefts from cryptocurrency exchanges.<ref>{{Cite news |last=Chavez-Dreyfuss |first=Gertrude |date=3 July 2018 |title=Cryptocurrency exchange theft surges in first half of 2018: report |work=Reuters |url=https://www.reuters.com/article/us-crypto-currencies-ciphertrace/cryptocurrency-exchange-theft-surges-in-first-half-of-2018-report-idUSKBN1JT1Q5 |url-status=live |access-date=10 July 2018 |archive-url=https://web.archive.org/web/20180704120854/https://www.reuters.com/article/us-crypto-currencies-ciphertrace/cryptocurrency-exchange-theft-surges-in-first-half-of-2018-report-idUSKBN1JT1Q5 |archive-date=4 July 2018}}</ref> | |||
=== Transactions === | |||
{{See also|Bitcoin network }} | |||
A transaction must have one or more inputs.<ref name="EconOfBTC" /> For the transaction to be valid, every input must be an unspent output of a previous transaction. Every input must be digitally signed. The use of multiple inputs corresponds to the use of multiple coins in a cash transaction. A transaction can also have multiple outputs, allowing one to make multiple payments in one go. A transaction output can be specified as an arbitrary multiple of satoshi. As in a cash transaction, the sum of inputs (coins used to pay) can exceed the intended sum of payments. In such a case, an additional output is used, returning the change back to the payer.<ref name="EconOfBTC" /> Any input satoshis not accounted for in the transaction outputs become the transaction fee.<ref name="EconOfBTC" /> | |||
=== |
===2020–present=== | ||
] |date=4 December 2024 |url=https://fred.stlouisfed.org/graph/?g=1BVJt |access-date=4 December 2024 |publisher=]}}</ref>}} December 1, 2014 - <br> December 4, 2024]] | |||
].<ref name="Blockchain.info">{{cite web |url=https://blockchain.info/charts |title=Charts |accessdate=2 November 2014 |publisher=]}}</ref>]] | |||
In 2020, some major companies and institutions started to acquire bitcoin: ] invested $250 million in bitcoin as a ],<ref>{{Cite news |date=13 September 2021 |title=MicroStrategy buys another $250m worth of bitcoin in hope of 100X price growth |url=https://www.independent.co.uk/tech/microstrategy-bitcoin-crypto-price-prediction-b1919178.html |access-date=22 November 2023 |work=] |first=Anthony |last=Cuthbertson |language=en |archive-date=22 November 2023 |archive-url=https://web.archive.org/web/20231122163924/https://www.independent.co.uk/tech/microstrategy-bitcoin-crypto-price-prediction-b1919178.html |url-status=live }}</ref> ], $50 million,<ref>{{cite news |author=Oliver Effron |title=Square just bought $50 million in bitcoin |url=https://www.cnn.com/2020/10/08/business/square-bitcoin-crypto-investment/index.html |access-date=22 October 2020 |work=CNN |archive-date=24 October 2020 |archive-url=https://web.archive.org/web/20201024101610/https://www.cnn.com/2020/10/08/business/square-bitcoin-crypto-investment/index.html |url-status=live }}</ref> and ], $100 million.<ref>{{cite news |url=https://www.bloomberg.com/news/articles/2020-12-10/169-year-old-insurer-massmutual-invests-100-million-in-bitcoin |title=169-Year-Old MassMutual Invests $100 Million in Bitcoin |date=11 December 2020 |work=Bloomberg |access-date=26 December 2020 |author=Olga Kharif |archive-date=19 December 2020 |archive-url=https://web.archive.org/web/20201219220543/https://www.bloomberg.com/news/articles/2020-12-10/169-year-old-insurer-massmutual-invests-100-million-in-bitcoin |url-status=live }}</ref> In November 2020, ] added support for bitcoin in the US.<ref>{{cite news |date=13 November 2020 |title=PayPal says all users in US can now buy, hold and sell cryptocurrencies |url=https://techcrunch.com/2020/11/12/paypal-says-all-users-in-u-s-can-now-buy-hold-and-sell-cryptocurrencies/ |access-date=26 November 2020 |work=Techcrunch |archive-date=24 November 2020 |archive-url=https://web.archive.org/web/20201124050031/https://techcrunch.com/2020/11/12/paypal-says-all-users-in-u-s-can-now-buy-hold-and-sell-cryptocurrencies/ |url-status=live }}</ref> | |||
]]] | |||
''Mining'' is a record-keeping service.{{refn | group = note | It is misleading to think that there is an analogy between gold mining and bitcoin mining. The fact is that gold miners are rewarded for producing gold, while bitcoin miners are not rewarded for producing bitcoins; they are rewarded for their record-keeping services.<ref name="Andolfatto2014-03" />}} Miners keep the blockchain consistent, complete, and unalterable by repeatedly verifying and collecting newly broadcast transactions into a new group of transactions called a ''block''.<ref name="econbc">{{cite news |title=The great chain of being sure about things |url=http://www.economist.com/news/briefing/21677228-technology-behind-bitcoin-lets-people-who-do-not-know-or-trust-each-other-build-dependable |accessdate=3 July 2016 |work=The Economist |publisher=The Economist Newspaper Limited |date=31 October 2015}}</ref> Each block contains a ] of the previous block,<ref name="econbc" /> using the ] hashing algorithm,<ref name="Antonopoulos2014" />{{rp|ch. 7}} which links it to the previous block<ref name="econbc" /> thus giving the blockchain its name. | |||
In February 2021, bitcoin's ] reached $1 trillion for the first time.<ref>{{Cite news |last1=Chavez-Dreyfuss |first1=Gertrude |last2=Wilson |first2=Tom |date=19 February 2021 |title=Bitcoin hits $1 trillion market cap, surges to fresh all-time peak |language=en-US |work=Reuters |url=https://www.reuters.com.article/idUSKBN2AJ0GC/ |access-date=24 November 2023}}</ref> In November 2021, the ] ] upgrade was activated, adding support for ]s, improved functionality of ]s and ].<ref>{{cite news |last=Sigalos |first=MacKenzie |date=14 November 2021 |title=Bitcoin's biggest upgrade in four years just happened – here's what changes |url=https://www.cnbc.com/2021/11/14/bitcoin-taproot-upgrade-what-it-means-for-investors.html |access-date=15 November 2021 |work=CNBC |archive-date=14 November 2021 |archive-url=https://web.archive.org/web/20211114215032/https://www.cnbc.com/2021/11/14/bitcoin-taproot-upgrade-what-it-means-for-investors.html |url-status=live }}</ref> Before, bitcoin only used a custom ] with the ] algorithm to produce ].<ref>{{Cite book |last1=Van Hijfte |first1=Stijn |title=Blockchain Platforms: A Look at the Underbelly of Distributed Platforms |publisher=Morgan & Claypool Publishers |year=2020 |isbn=978-1681738925}}</ref>{{rp|101}} In September 2021, bitcoin became ] in ], alongside the US dollar.<ref name=BTCSVSept7FT/> In October 2021, the first bitcoin futures ] (ETF), called BITO, from ] was approved by the ] and listed on the ].<ref>{{Cite web |url=https://www.wsj.com/articles/a-bitcoin-etf-is-almost-here-what-does-that-mean-for-investors-11634376601 |title=A Bitcoin ETF Is Here. What Does That Mean for Investors? |date=19 October 2021 |access-date=11 January 2024 |website=The Wall Street Journal |last=Wursthorn |first=Michael |url-access=subscription |archive-date=10 January 2024 |archive-url=https://web.archive.org/web/20240110200308/https://www.wsj.com/articles/a-bitcoin-etf-is-almost-here-what-does-that-mean-for-investors-11634376601 |url-status=live }}</ref> | |||
In order to be accepted by the rest of the network, a new block must contain a so-called '']''.<ref name="econbc" /> The proof-of-work requires miners to find a number called a '']'', such that when the block content is ] along with the nonce, the result is numerically smaller than the network's ''difficulty target''.<ref name="Antonopoulos2014" />{{rp|ch. 8}} This proof is easy for any node in the network to verify, but extremely time-consuming to generate, as for a secure cryptographic hash, miners must try many different nonce values (usually the sequence of tested values is 0, 1, 2, 3, …<ref name="Antonopoulos2014" />{{rp|ch. 8}}) before meeting the difficulty target. | |||
In early 2022, during the ] opposing ], organizers turned to bitcoin to receive donations after traditional financial platforms restricted access to funding.<ref>{{Cite web |last=Loh |first=Matthew |title=Canada says it will freeze the bank accounts of 'Freedom Convoy' truckers who continue their anti-vaccine mandate blockades |url=https://www.businessinsider.com/trudeau-canada-freeze-bank-accounts-freedom-convoy-truckers-2022-2 |access-date=2025-01-19 |website=Business Insider |language=en-US}}</ref><ref>{{Cite web |date=2024-12-08 |title=Crypto enthusiasts keep funding convoy protests as traditional banks take action against it - The Globe and Mail |url=https://web.archive.org/web/20241208224444/https://www.theglobeandmail.com/business/article-crypto-enthusiasts-keep-funding-convoy-protests-as-traditional-banks/ |access-date=2025-01-19 |website=The Globe and Mail}}</ref> Proponents highlighted bitcoin's use as a tool for fundraising in situations where access to conventional financial systems may be restricted.<ref>{{Cite web |date=2024-06-20 |title=Meet Greg Foss: A Former Bitcoin Fundraiser For Canada’s ‘Freedom Convoy’ Protest |url=https://web.archive.org/web/20240620070940/https://www.forbes.com/sites/jasonbrett/2022/02/17/meet-greg-foss-a-former-bitcoin-fundraiser-for-canadas-freedom-convoy-protest/ |access-date=2025-01-19 |website=Forbes}}</ref><ref>{{Cite web |date=2022-03-13 |title=Elon Musk–backed ‘freedom truckers’ in Canada get Bitcoin lifeline after GoFundMe freezes millions in donations |url=https://web.archive.org/web/20220313170541/https://finance.yahoo.com/news/elon-musk-backed-freedom-truckers-200403223.html |access-date=2025-01-19 |website=Yahoo! Finance}}</ref> In May and June 2022, the bitcoin price fell following the collapses of ], a ],<ref>{{cite news|last=Browne|first=Ryan|date=10 May 2022|title=Bitcoin investors are panicking as a controversial crypto experiment unravels|url=https://www.cnbc.com/2022/05/10/bitcoin-btc-investors-panic-as-terrausd-ust-sinks-below-1-peg.html|work=CNBC|access-date=11 May 2022|archive-date=11 May 2022|archive-url=https://web.archive.org/web/20220511021259/https://www.cnbc.com/2022/05/10/bitcoin-btc-investors-panic-as-terrausd-ust-sinks-below-1-peg.html|url-status=live}}</ref> and the ], a cryptocurrency loan company.<ref>{{cite news|last1=Milmo|first1=Dan|title=Bitcoin value slumps below $20,000 in cryptocurrencies turmoil|url=https://www.theguardian.com/technology/2022/jun/18/bitcoin-value-falls-cryptocurrency-markets-turmoil|access-date=19 June 2022|work=The Guardian|date=18 June 2022|language=en|archive-date=18 June 2022|archive-url=https://web.archive.org/web/20220618231120/https://www.theguardian.com/technology/2022/jun/18/bitcoin-value-falls-cryptocurrency-markets-turmoil|url-status=live}}</ref><ref>{{cite news|last=Yaffe-Bellany|first=David|date=13 June 2022|title=Celsius Network Leads Crypto Markets Into Another Free Fall|url=https://www.nytimes.com/2022/06/13/technology/bitcoin-ether-price.html|work=The New York Times|access-date=14 June 2022|archive-date=14 June 2022|archive-url=https://web.archive.org/web/20220614030021/https://www.nytimes.com/2022/06/13/technology/bitcoin-ether-price.html|url-status=live}}</ref> | |||
Every 2016 blocks (approximately 14 days), the difficulty target is adjusted based on the network's recent performance, with the aim of keeping the average time between new blocks at ten minutes. In this way the system automatically adapts to the total amount of mining power on the network.<ref name="Antonopoulos2014" />{{rp|ch. 8}} | |||
In 2023, ordinals—]s (NFTs)—on bitcoin, went live.<ref>{{Cite journal |last=Behrendt |first=Philipp |date=2023 |title=Taxation of the New Age: New Guidance for the World of Digital Assets |url=https://heinonline.org/HOL/Page?handle=hein.journals/jtaxpp25&id=105&div=&collection= |journal=Journal of Tax Practice & Procedure |volume=25 |pages=47 |access-date=21 November 2023 |archive-date=21 November 2023 |archive-url=https://web.archive.org/web/20231121164911/https://heinonline.org/HOL/Page?handle=hein.journals/jtaxpp25&id=105&div=&collection= |url-status=live }}</ref> As of June 2023, River Financial estimated that bitcoin had 81.7 million users, about 1% of the global population.<ref>{{cite web |date=2024-03-01 |title=As banks buy up bitcoins, who else are the 'Bitcoin whales'? |url=https://www.bbc.com/news/technology-68434579 |access-date=2024-03-14 |website=BBC Home}}</ref> In January 2024, the first 11 US ] bitcoin ]s began trading, offering direct exposure to bitcoin for the first time on American stock exchanges.<ref>{{Cite news |last=Schmitt |first=Will |date=12 January 2024 |title=Bitcoin trading volumes surge after debut of long-awaited US ETFs |url=https://www.ft.com/content/f30ece62-0f1c-492a-8ccd-63ec9730573c |access-date=12 January 2024 |work=Financial Times |archive-date=12 January 2024 |archive-url=https://web.archive.org/web/20240112025105/https://www.ft.com/content/f30ece62-0f1c-492a-8ccd-63ec9730573c |url-status=live }}</ref><ref>{{cite news|last1=Lang|first1=Hannah|title=US bitcoin ETFs see $4.6B in volume in first day of trading|url=https://www.reuters.com/technology/spot-bitcoin-etfs-start-trading-big-boost-crypto-industry-2024-01-11/|access-date=12 January 2024|work=Reuters|date=11 January 2024|language=en}}</ref> In December 2024, bitcoin price reached $100,000 for the first time, as ] ] promised to make the US the "crypto capital of the planet" and to stockpile bitcoin.<ref>{{cite news|url=https://www.reuters.com/technology/bitcoin-tops-100000-optimism-over-trump-crypto-plans-2024-12-05/|title=Bitcoin storms above $100,000 as Trump 2.0 fuels crypto euphoria|work=Reuters|date=2024-12-05}}</ref> The same month, ], the world's largest ], recommended investors to allocate up to 2% of their ] to bitcoin.<ref>{{cite news|url=https://www.reuters.com/markets/us/blackrock-recommends-bitcoin-portfolio-weighting-up-2-interested-investors-2024-12-12/ | title=BlackRock recommends bitcoin portfolio weighting of up to 2% for interested investors|date=2024-12-12|first=Suzanne|last= McGee|work=Reuters}}</ref> | |||
Between 1 March 2014 and 1 March 2015, the average number of nonces miners had to try before creating a new block increased from 16.4 quintillion to 200.5 quintillion.<ref name="diffhistory">{{cite web |url=https://blockchain.info/charts/difficulty?timespan=all&showDataPoints=false&daysAverageString=1&show_header=true&scale=0&address= |title=Difficulty History |publisher=Blockchain.info |accessdate=26 March 2015 |type=The ratio of all hashes over valid hashes is D x 4295032833, where D is the published "Difficulty" figure.}}</ref> | |||
==Design== | |||
The proof-of-work system, alongside the chaining of blocks, makes modifications of the blockchain extremely hard, as an attacker must modify all subsequent blocks in order for the modifications of one block to be accepted.<ref>{{cite news |last1=Hampton |first1=Nikolai |title=Understanding the blockchain hype: Why much of it is nothing more than snake oil and spin |url=http://www.computerworld.com.au/article/606253/understanding-blockchain-hype-why-much-it-nothing-more-than-snake-oil-spin/ |accessdate=5 September 2016 |work=Computerworld |publisher=IDG |date=5 September 2016}}</ref> As new blocks are mined all the time, the difficulty of modifying a block increases as time passes and the number of subsequent blocks (also called ''confirmations'' of the given block) increases.<ref name="econbc" /> | |||
{{Main|Bitcoin protocol}} | |||
=== |
===Units and divisibility=== | ||
The ] of the bitcoin system is the ''bitcoin''. It is most commonly represented with the ] ₿<ref name="unicode-10" /> and the ] BTC. However, the BTC code does not conform to ] as BT is the country code of Bhutan,<ref name="ssrn.3383734">{{Cite journal |last1=Alexander |first1=Carol |last2=Imeraj |first2=Arben |date=2019 |title=Introducing the BITIX: The Bitcoin Fear Gauge |url=https://www.ssrn.com/abstract=3383734 |journal=] |language=en |doi=10.2139/ssrn.3383734 |issn=1556-5068|quote=XBT satisfies the norm ‘ISO 4217’ by the International Organisation for Standardisation (ISO) as BTC goes against the name of Bhutan’s currency. In general, transaction instruments that are not national currencies, like gold or silver, begin with an X. However, the symbol XBT is not officially recognised by ISO.}}</ref> and ISO 4217 requires the first letter used in global commodities to be 'X'.<ref name="ssrn.3383734"/> XBT, a code that conforms to ] though not officially part of it,<ref name="ssrn.3383734"/> is used by ]<ref>{{Cite news |last=Romain Dillet |date=9 August 2013 |title=Bitcoin Ticker Available On Bloomberg Terminal For Employees |work=] |url=https://techcrunch.com/2013/08/09/bitcoin-ticker-available-on-bloomberg-terminal/ |url-status=live |access-date=2 November 2014 |archive-url=https://web.archive.org/web/20141101232825/http://techcrunch.com/2013/08/09/bitcoin-ticker-available-on-bloomberg-terminal/ |archive-date=1 November 2014}}</ref> | |||
It has become common for miners to join ]s,<ref name=boise>{{cite web |url=http://arbiteronline.com/2014/04/03/bitcoins-likely-viable-future/ |title=Bitcoins lose viability |publisher=Boise State Student Media |work=The Arbiter |date=3 April 2014 |accessdate=14 April 2014 |author=Mills, Kelly}}</ref> which combine the computational resources of their members in order to increase the frequency of generating new blocks. The reward for each block is then split proportionately among the members, creating a more predictable stream of income for each miner without necessarily changing their long-term average income,<ref>{{cite web |last1=Wang |first1=Luqin |last2=Liu |first2=Yong |title=Exploring Miner Evolution in Bitcoin Network |url=http://wan.poly.edu/pam2015/papers/23.pdf |publisher=NYU Polytechnic School of Engineering |accessdate=15 February 2015}}</ref> although a fee may be charged for the service.<ref>{{cite arXiv |last1=Rosenfeld |first1=Meni |title=Analysis of Bitcoin Pooled Mining Reward Systems |arxiv=1112.4980}}</ref><ref>{{cite news |author1=Peter Svensson |title=Bitcoin faces biggest threat yet: a miner takeover |url=http://phys.org/news/2014-06-bitcoin-biggest-threat-miner-takeover.html |accessdate=8 January 2015 |date=17 June 2014}}</ref> | |||
No uniform ] convention exists; some sources use ''Bitcoin'', capitalized, to refer to the technology and ], and ''bitcoin'', lowercase, for the unit of account.<ref>{{Cite magazine |last=Bustillos, Maria |date=2 April 2013 |title=The Bitcoin Boom |url=https://www.newyorker.com/tech/elements/the-bitcoin-boom |url-status=live |magazine=] |archive-url=https://web.archive.org/web/20140727185121/http://www.newyorker.com/tech/elements/the-bitcoin-boom |archive-date=27 July 2014 |access-date=22 December 2013}}</ref> The '']'' and the '']'' use the capitalized and lowercase variants without distinction.<ref>, '']''</ref><ref> {{Webarchive|url=https://web.archive.org/web/20220503092252/http://dictionary.cambridge.org/dictionary/english/bitcoin |date=3 May 2022 }}, '']''</ref> | |||
The rewards of mining have led to ever-more-specialized technology being utilized. The most efficient mining hardware makes use of custom designed ]s, which outperform general-purpose ] while using less power.<ref>{{cite news |url=http://www.theregister.co.uk/2014/01/17/ten_bitcoin_miners/ |title=Manic miners: Ten Bitcoin generating machines |publisher=The Register |first=Simon |last=Rockman |date=17 January 2014 |accessdate=13 February 2014}}</ref> As of 2015, a miner who is not using purpose-built hardware is unlikely to earn enough to cover the cost of the electricity used in their efforts, even if they are a member of a pool.<ref name=purdue>{{cite web |url=http://www.purdueexponent.org/features/article_46e4aefa-dc11-5c5e-972b-80b4e45a70e1.html |title=Bitcoin offers speedy currency, poses high risks |publisher=The Exponent Online |work=Purdue Exponent |date=9 April 2014 |accessdate=14 April 2014 |author=Bays, Jason}}</ref> | |||
One bitcoin is divisible to eight decimal places.<ref name="Antonopoulos2014" />{{rp|ch. 5}} Units for smaller amounts of bitcoin are the millibitcoin (mBTC), equal to {{frac|1|1000}} bitcoin, and the satoshi{{efn|name=satoshi|Named after ]}} (sat), representing {{frac|1|{{val|100000000}}}} (one hundred millionth) bitcoin, the smallest amount possible.<ref name="satoshi unit" /> 100,000 satoshis are one mBTC.<ref>{{Cite news |last1=Katie Pisa |last2=Natasha Maguder |date=9 July 2014 |title=Bitcoin your way to a double espresso |work=CNN |url=http://edition.cnn.com/2014/06/18/business/bitcoin-your-way-to-a-double-espresso/ |url-status=live |access-date=23 April 2015 |archive-url=https://web.archive.org/web/20150618072429/http://edition.cnn.com/2014/06/18/business/bitcoin-your-way-to-a-double-espresso/ |archive-date=18 June 2015 }}</ref> | |||
====Energy consumption==== | |||
In 2013, Mark Gimein estimated electricity use to be about 982 megawatt-hours a day, which could be used to power roughly 31,000 US homes.<ref>{{cite news |url=http://www.bloomberg.com/news/articles/2013-04-12/virtual-bitcoin-mining-is-a-real-world-environmental-disaster |title=Virtual Bitcoin Mining Is a Real-World Environmental Disaster |publisher=Bloomberg LP |work=Bloomberg Business |date=13 April 2013 |accessdate=22 April 2015 |author=Gimein, Mark}}</ref> In 2014, Karl J. O'Dwyer and David Malone estimated that specialized computers mining bitcoins required 0.1 to 10 GW of power.<ref>{{cite journal|last1=O'Dwyer |first1=Karl J. |last2=Malone |first2=David |title=Bitcoin Mining and its Energy Footprint |journal=ISSC |date=26 June 2014 |url=http://eprints.maynoothuniversity.ie/6009/1/DM-Bitcoin.pdf |accessdate=18 September 2016 |publisher=Hamilton Institute}}</ref> As of 2015, ''The Economist'' estimated that even if all miners used modern facilities, the combined electricity consumption would be 1.46 terawatt-hours per year—equal to the consumption of about 135,000 American homes.<ref name=ec1305>{{cite news |title=The magic of mining |url=http://www.economist.com/news/business/21638124-minting-digital-currency-has-become-big-ruthlessly-competitive-business-magic |accessdate=13 January 2015 |work=] |date=13 January 2015}}</ref> | |||
===Blockchain=== | |||
Bitcoin miners have set up in places like ] where ] is cheap and cooling ] air is free. Journalist Matt O'Brien has pointed out that pollution connected with electricity usage in "energy-intensive" bitcoin mining are "paying less than they should" due to "environmental spillovers on everyone else, or what economists call ]." Thus bitcoin is not lowering costs, but "shifting them" into pollution costs.<ref name="dh150613">{{cite news|last1=O'Brien|first1=Matt|title=The scam called Bitcoin|url=http://www.dailyherald.com/article/20150613/business/150619551/|accessdate=20 September 2016|work=Daily Herald|date=13 June 2015}}</ref> | |||
{{further|Blockchain#Structure and design}} | |||
As a ] system, bitcoin operates without a central authority or single administrator,<ref name=Gervais2014>{{Cite journal |last1=Gervais |first1=Arthur |last2=Karame |first2=Ghassan O. |last3=Capkun |first3=Vedran |last4=Capkun |first4=Srdjan |date=May 2014 |title=Is Bitcoin a Decentralized Currency? |url=https://ieeexplore.ieee.org/document/6824541 |journal=] |volume=12 |issue=3 |pages=54–60 |doi=10.1109/MSP.2014.49 |s2cid=13948781 |issn=1540-7993 |access-date=22 November 2023 |archive-date=19 November 2023 |archive-url=https://web.archive.org/web/20231119101600/https://ieeexplore.ieee.org/document/6824541/ |url-status=live }}</ref> so that anyone can create a new bitcoin address and transact without needing any approval.{{r|Antonopoulos2014|page=ch. 1}} This is accomplished through a specialized ] called a '']'' that records bitcoin transactions.{{r|econbc}} | |||
The blockchain is implemented as an ordered list of ''blocks''. Each block contains a ] ] of the previous block,<ref name="econbc" /> chaining them in chronological order.<ref name="Antonopoulos2014" />{{rp|ch. 7}}<ref name="econbc" /> The blockchain is maintained by a ] network.<ref name=JEP/>{{rp|215–219}} Individual blocks, public addresses, and transactions within blocks are public information, and can be examined using a blockchain explorer.<ref>{{Cite web| url=https://nvlpubs.nist.gov/nistpubs/ir/2021/NIST.IR.8301.pdf| publisher=National Institute of Standards Technology (NIST)| access-date=29 December 2022| title=Blockchain Networks: Token Design and Management Overview| page=32| archive-date=24 December 2022| archive-url=https://web.archive.org/web/20221224003108/https://nvlpubs.nist.gov/nistpubs/ir/2021/NIST.IR.8301.pdf| url-status=live}}</ref> | |||
=== Supply === | |||
] | |||
The successful miner finding the new block is rewarded with newly created bitcoins and transaction fees.<ref name="bloombergvance111413">{{cite web |url=http://www.businessweek.com/articles/2013-11-14/2014-outlook-bitcoin-mining-chips-a-high-tech-arms-race |title=2014 Outlook: Bitcoin Mining Chips, a High-Tech Arms Race |publisher=Businessweek |date=14 November 2013 |author=Ashlee Vance |accessdate=24 November 2013}}</ref> {{as of|2016|07|09}},<ref name="BlockChain.info">{{cite web |url=https://blockchain.info/block/000000000000000002cce816c0ab2c5c269cb081896b7dcb34b8422d6b74ffa1 |title=Block #420000 |publisher=Blockchain.info |accessdate=11 September 2016}}</ref> the reward amounted to 12.5 newly created bitcoins per block added to the blockchain. To claim the reward, a special transaction called a ''coinbase'' is included with the processed payments.<ref name="Antonopoulos2014" />{{rp|ch. 8}} All bitcoins in existence have been created in such coinbase transactions. The ] specifies that the reward for adding a block will be halved every 210,000 blocks (approximately every four years). Eventually, the reward will decrease to zero, and the limit of 21 million bitcoins{{refn|group=note|The exact number is 20,999,999.9769 bitcoins.<ref name="Antonopoulos2014" />{{rp|ch. 8}}}} will be reached ] 2140; the record keeping will then be rewarded by transaction fees solely.<ref name="KWY">{{cite web |url=http://qz.com/154877/by-reading-this-page-you-are-mining-bitcoins/ |title=By reading this article, you're mining bitcoins |publisher=Atlantic Media Co |work=qz.com |date=17 December 2013 |accessdate=17 December 2013 |author1=Ritchie S. King |author2=Sam Williams |author3=David Yanofsky}}</ref> | |||
Nodes validate and broadcast transactions, each maintaining a copy of the blockchain for ownership verification.<ref>{{Cite news |last=Sparkes, Matthew |date=9 June 2014 |title=The coming digital anarchy |work=The Daily Telegraph |url=https://www.telegraph.co.uk/technology/news/10881213/The-coming-digital-anarchy.html |url-status=live |access-date=7 January 2015 |archive-url=https://web.archive.org/web/20150123190900/http://www.telegraph.co.uk/technology/news/10881213/The-coming-digital-anarchy.html |archive-date=23 January 2015}}</ref> A new block is created every 10 minutes on average, updating the blockchain across all nodes without central oversight. This process tracks bitcoin spending, ensuring each bitcoin is ]. Unlike a traditional ledger that tracks physical currency, bitcoins exist digitally as ].<ref name="Antonopoulos2014" />{{rp|ch. 5}} | |||
In other words, bitcoin's inventor Nakamoto set a monetary policy at the start of the bitcoin concept that there would only ever be 21 million bitcoins in total, their numbers being released roughly every ten minutes, and the rate at which they would be generated would drop by half every four years until all were in circulation.<ref>{{cite news |last1=Shin |first1=Laura |title=Bitcoin Production Will Drop By Half In July, How Will That Affect The Price? |url=http://www.forbes.com/sites/laurashin/2016/05/24/bitcoin-production-will-drop-by-half-in-july-how-will-that-affect-the-price/#79bdaa0999e1|accessdate=13 July 2016 |work=Forbes |date=24 May 2016}}</ref> | |||
===Addresses and transactions=== | |||
=== Transaction fees === | |||
] | |||
Paying a transaction fee is optional.<ref name="EconOfBTC" /> Miners can choose which transactions to process<ref name="EconOfBTC" /> and prioritize those that pay higher fees. | |||
In the blockchain, bitcoins are linked to specific addresses that are hashes of a ]. Creating an address involves generating a random ] and then computing the corresponding address. This process is almost instant, but the reverse (finding the private key for a given address) is nearly impossible.<ref name="Antonopoulos2014" />{{rp|ch. 4}} Publishing a bitcoin address does not risk its private key, and it is extremely unlikely to accidentally generate a used key with funds. To use bitcoins, owners need their private key to ] transactions, which are verified by the network using the public key, keeping the private key secret.<ref name="Antonopoulos2014" />{{rp|ch. 5}} | |||
Bitcoin transactions use a ]-like ],{{r|Antonopoulos2014|p=ch. 5}} involving one or more inputs and outputs. When sending bitcoins, a user specifies the recipients' addresses and the amount for each output. This allows sending bitcoins to several recipients in a single transaction. To prevent double-spending, each input must refer to a previous unspent output in the blockchain.<ref name="EconOfBTC">{{Cite conference |last1=Kroll |first1=Joshua A. |last2=Davey |first2=Ian C. |last3=Felten |first3=E. |title=The Economics of Bitcoin Mining, or Bitcoin in the Presence of Adversaries |conference=The Twelfth Workshop on the Economics of Information Security (WEIS 2013) |location=Washington, DC|date= 11–12 June 2013|s2cid=2794725 }}</ref> Using multiple inputs is similar to using multiple coins in a cash transaction. As in a cash transaction, the sum of inputs can exceed the intended sum of payments. In such a case, an additional output can return the change back to the payer.<ref name="EconOfBTC" /> Unallocated input satoshis in the transaction become the transaction fee.<ref name="EconOfBTC" /> | |||
=== Wallets === | |||
{{See also|Digital wallet}} | |||
] | |||
] | |||
] | |||
A ''wallet'' stores the information necessary to transact bitcoins. While wallets are often described as a place to hold<ref>{{cite web |url=http://www.motherjones.com/politics/2013/04/what-is-bitcoin-explained |title=Bitcoin, Explained |publisher=Mother Jones |work=motherjones.com |date=10 April 2013 |accessdate=26 April 2014 |author1=Adam Serwer |author2=Dana Liebelson |lastauthoramp=yes}}</ref> or store bitcoins,<ref name=3ceos /> due to the nature of the system, bitcoins are inseparable from the blockchain transaction ledger. A better way to describe a wallet is something that "stores the digital credentials for your bitcoin holdings"<ref name=3ceos>{{cite news |url=http://www.forbes.com/sites/johnvillasenor/2014/04/26/secure-bitcoin-storage-a-qa-with-three-bitcoin-company-ceos/ |title=Secure Bitcoin Storage: A Q&A With Three Bitcoin Company CEOs |publisher=Forbes |work=forbes.com |date=26 April 2014 |accessdate=26 April 2014 |author=Villasenor, John}}</ref> and allows you to access (and spend) them. Bitcoin uses ], in which two cryptographic keys, one public and one private, are generated.<ref name="Economist113013Pressure">{{cite news |url=http://www.economist.com/news/technology-quarterly/21590766-virtual-currency-it-mathematically-elegant-increasingly-popular-and-highly |title=Bitcoin: Bitcoin under pressure |work=The Economist |date=30 November 2013 |accessdate=30 November 2013}}</ref> At its most basic, a wallet is a collection of these keys. | |||
Losing a private key means losing access to the bitcoins, with no other proof of ownership accepted by the ].<ref name=JEP/> For instance, in 2013, a user lost ₿7,500, valued at US$7.5 million, by accidentally discarding a ] with the private key.<ref>{{Cite news |date=29 November 2013 |title=Man Throws Away 7,500 Bitcoins, Now Worth $7.5 Million |work=CBS DC |url=http://washington.cbslocal.com/2013/11/29/man-throws-away-7500-bitcoins-now-worth-7-5-million/ |url-status=live |access-date=23 January 2014 |archive-url=https://web.archive.org/web/20140115062630/http://washington.cbslocal.com/2013/11/29/man-throws-away-7500-bitcoins-now-worth-7-5-million/ |archive-date=15 January 2014}}</ref> It is estimated that around 20% of all bitcoins are lost.<ref>{{Cite news |last=Krause |first=Elliott |date=5 July 2018 |title=A Fifth of All Bitcoin Is Missing. These Crypto Hunters Can Help |work=The Wall Street Journal |url=https://www.wsj.com/articles/a-fifth-of-all-bitcoin-is-missing-these-crypto-hunters-can-help-1530798731 |url-status=live |access-date=8 July 2018 |archive-url=https://web.archive.org/web/20180709010939/https://www.wsj.com/articles/a-fifth-of-all-bitcoin-is-missing-these-crypto-hunters-can-help-1530798731 |archive-date=9 July 2018}}</ref> The private key must also be kept secret as its exposure, such as through a ], can lead to theft of the associated bitcoins.<ref name="Antonopoulos2014" />{{rp|ch. 10}}<ref>{{Cite news |last=Jeffries |first=Adrianne |date=19 December 2013 |title=How to steal Bitcoin in three easy steps |work=The Verge |url=https://www.theverge.com/2013/12/19/5183356/how-to-steal-bitcoin-in-three-easy-steps |url-status=live |access-date=17 January 2014 |archive-url=https://web.archive.org/web/20190727141228/https://www.theverge.com/2013/12/19/5183356/how-to-steal-bitcoin-in-three-easy-steps |archive-date=27 July 2019}}</ref> {{As of|2017|12}}, approximately ₿980,000 had been stolen from ]s.<ref>{{Cite news |last1=Harney |first1=Alexandra |last2=Stecklow |first2=Steve |date=16 November 2017 |title=Twice burned – How Mt. Gox's bitcoin customers could lose again |work=Reuters |url=https://www.reuters.com/investigates/special-report/bitcoin-gox/ |url-status=live |access-date=6 September 2018 |archive-url=https://web.archive.org/web/20190829052101/https://www.reuters.com/investigates/special-report/bitcoin-gox/ |archive-date=29 August 2019}}</ref> | |||
There are several types of wallets. ''Software wallets'' connect to the network and allow spending bitcoins in addition to holding the credentials that prove ownership.<ref name="Bitcoin Clients" /> Software wallets can be split further in two categories: full clients and lightweight clients. | |||
* '''Full clients''' verify transactions directly on a local copy of the blockchain (over 80 GB as of November 2016<ref>{{cite web |url=https://blockchain.info/charts/blocks-size |title=Blockchain Size |publisher=Blockchain.info |accessdate=24 April 2016}}</ref>). Because of its size / complexity, the entire blockchain is not suitable for all computing devices. | |||
* '''Lightweight clients''' on the other hand consult a full client to send and receive transactions without requiring a local copy of the entire blockchain (see ] – SPV). This makes lightweight clients much faster to setup and allows them to be used on low-power, low-bandwidth devices such as smartphones. When using a lightweight wallet however, the user must trust the server to a certain degree. When using a lightweight client, the server can not steal bitcoins, but it can report faulty values back to the user. With both types of software wallets, the users are responsible for keeping their private keys in a secure place.<ref>{{cite web |last1=Gervais |first1=Arthur |last2=O. Karame |first2=Ghassan |last3=Gruber |first3=Damian |last4=Capkun |first4=Srdjan |title=On the Privacy Provisions of Bloom Filters in Lightweight Bitcoin Clients |url=https://eprint.iacr.org/2014/763.pdf |accessdate=3 September 2016}}</ref> | |||
===Mining=== | |||
Besides software wallets, Internet services called ''online wallets'' offer similar functionality but may be easier to use. In this case, credentials to access funds are stored with the online wallet provider rather than on the user's hardware.<ref>{{cite news |title=Be Your Own Bank: Bitcoin Wallet for Apple |url=http://www.forbes.com/sites/jonmatonis/2012/04/26/be-your-own-bank-bitcoin-wallet-for-apple/ |author=Jon Matonis |date=26 April 2012 |accessdate=17 November 2014 |publisher=Forbes}}</ref><ref>{{cite news |author1=Bill Barhydt |title=3 reasons Wall Street can't stay away from bitcoin |url=http://www.cnbc.com/id/101711220 |accessdate=2 April 2015 |publisher=NBCUniversal |date=4 June 2014}}</ref> As a result, the user must have complete trust in the wallet provider. A malicious provider or a breach in server security may cause entrusted bitcoins to be stolen. An example of such security breach occurred with ] in 2011.<ref name="mtgoxdetails" /> | |||
{{See also|Bitcoin protocol#Mining}} | |||
] with large amounts of mining hardware]] | |||
The mining process in bitcoin involves maintaining the blockchain through computer ]. Miners group and broadcast new transactions into blocks, which are then verified by the network.<ref name="econbc">{{Cite news |date=31 October 2015 |title=The great chain of being sure about things |newspaper=The Economist |url=https://www.economist.com/briefing/2015/10/31/the-great-chain-of-being-sure-about-things |access-date=22 November 2023 |archive-date=4 December 2023 |archive-url=https://web.archive.org/web/20231204154941/https://www.economist.com/briefing/2015/10/31/the-great-chain-of-being-sure-about-things |url-status=live }}</ref> Each block must contain a proof of work (PoW) to be accepted,<ref name="econbc" /> involving finding a ] number that, combined with the block content, produces a ] numerically smaller than the network's ''difficulty target''.<ref name="Antonopoulos2014" />{{rp|ch. 8}} This PoW is simple to verify but hard to generate, requiring many attempts.<ref name="Antonopoulos2014" />{{rp|ch. 8}} PoW forms the basis of bitcoin's ].<ref name=Mingxiao2017>{{Cite conference |last1=Mingxiao |first1=Du |last2=Xiaofeng |first2=Ma |last3=Zhe |first3=Zhang |last4=Xiangwei |first4=Wang |last5=Qijun |first5=Chen |date=5–8 October 2017 |title=A review on consensus algorithm of blockchain |url=https://ieeexplore.ieee.org/document/8123011 |publisher=IEEE |pages=2567–2572 |doi=10.1109/SMC.2017.8123011 |isbn=978-1-5386-1645-1 |conference=2017 IEEE International Conference on Systems, Man, and Cybernetics (SMC) |location=Banff, AB, Canada |access-date=29 November 2023 |archive-date=24 November 2023 |archive-url=https://web.archive.org/web/20231124215821/http://ieeexplore.ieee.org/document/8123011 |url-status=live }}</ref> | |||
The difficulty of generating a block is ] based on the ] by changing the difficulty target, which is recalibrated every 2,016 blocks (approximately two weeks) to maintain an average time of ten minutes between new blocks. The process requires significant computational power and specialized ].<ref name="Antonopoulos2014" />{{rp|ch. 8}}<ref>{{cite news |date=4 January 2014 |url=http://www.taipeitimes.com/News/biz/archives/2014/01/04/2003580449 |title=Bitcoin boom benefiting TSMC: report |newspaper=] |access-date=22 October 2021 |archive-date=29 January 2023 |archive-url=https://web.archive.org/web/20230129102127/https://www.taipeitimes.com/News/biz/archives/2014/01/04/2003580449 |url-status=live }}</ref> | |||
''Physical wallets'' also exist and are more secure, as they store the credentials necessary to spend bitcoins offline.<ref name=3ceos /> Examples combine a novelty coin with these credentials printed on metal,<ref name="theverge">{{cite web |last=Staff |first=Verge |url=http://www.theverge.com/2013/12/13/5207256/casascius-maker-of-shiny-physical-bitcoins-shut-down-by-treasury |title=Casascius, maker of shiny physical bitcoins, shut down by Treasury Department |publisher=The Verge |date=13 December 2013 |accessdate=10 January 2014}}</ref> Others are simply paper printouts. Another type of wallet called a ''hardware wallet'' keeps credentials offline while facilitating transactions.<ref>{{cite news |title=Meet Trezor, A Bitcoin Safe That Fits Into Your Pocket |url=http://www.forbes.com/sites/ericxlmu/2014/10/15/meet-trezor-a-bitcoin-safe-that-can-fit-into-your-pocket/ |author=Eric Mu |date=15 October 2014 |accessdate=31 October 2014 |publisher=Forbes |work=Forbes Asia}}</ref> | |||
Miners who successfully find a new block can collect transaction fees from the included transactions and a set reward in bitcoins.<ref name="bloombergvance111413">{{Cite magazine |last=Ashlee |first= Vance |author-link=Ashlee Vance |date=14 November 2013 |title=2014 Outlook: Bitcoin Mining Chips, a High-Tech Arms Race |url=http://www.businessweek.com/articles/2013-11-14/2014-outlook-bitcoin-mining-chips-a-high-tech-arms-race |url-status=dead |magazine=] |archive-url=https://web.archive.org/web/20131121225123/http://www.businessweek.com/articles/2013-11-14/2014-outlook-bitcoin-mining-chips-a-high-tech-arms-race |archive-date=21 November 2013 |access-date=24 November 2013}}</ref> To claim this reward, a special transaction called a ''coinbase'' is included in the block, with the miner as the payee. All bitcoins in existence have been created through this type of transaction.<ref name="Antonopoulos2014" />{{rp|ch. 8}} This reward is halved every 210,000 blocks until ₿21 million,{{efn|name=supply|The exact number is ₿20,999,999.9769.{{r|Antonopoulos2014|page=ch. 8}}}} with new bitcoin issuance slated to end around 2140. Afterward, miners will only earn from transaction fees. These fees are determined by the transaction's size and the amount of data stored, measured in satoshis per byte.<ref>{{cite news |first1=Ritchie S. |last1=King |first2=Sam |last2=Williams |first3=David |last3=Yanofsky |date=17 December 2013 |title=By reading this article, you're mining bitcoins |url=http://qz.com/154877/by-reading-this-page-you-are-mining-bitcoins |work=] |access-date=17 December 2013 |archive-date=17 December 2013 |archive-url=https://web.archive.org/web/20131217221429/http://qz.com/154877/by-reading-this-page-you-are-mining-bitcoins/ |url-status=live }}</ref><ref name="EconOfBTC" /><ref name="Antonopoulos2014" />{{rp|ch. 8}} | |||
==== Reference implementation ==== | |||
The first wallet program was released in 2009 by ] as ] code.<ref name="NY2011" /> Sometimes referred to as the "Satoshi client," this is also known as the ] because it serves to define the bitcoin protocol and acts as a standard for other implementations.<ref name="Bitcoin Clients" /> In version 0.5 the client moved from the ] user interface toolkit to ], and the whole bundle was referred to as Bitcoin-Qt.<ref name="Bitcoin Clients">{{Cite thesis |url=http://publications.theseus.fi/bitstream/handle/10024/47166/Skudnov_Rostislav.pdf?sequence=1 |first=Rostislav |last=Skudnov |title=Bitcoin Clients |type=Bachelor's Thesis |year=2012 |publisher=] |accessdate=16 January 2014}}</ref> After the release of version 0.9, the software bundle was renamed ] to distinguish itself from the network.<ref>{{cite web |title=Bitcoin Core version 0.9.0 released |url=https://bitcoin.org/en/release/v0.9.0 |website=bitcoin.org |accessdate=8 January 2015}}</ref><ref>{{cite news |last1=Metz |first1=Cade |title=The Bitcoin Schism Shows the Genius of Open Source |url=http://www.wired.com/2015/08/bitcoin-schism-shows-genius-open-source/ |accessdate=3 July 2016 |work=Wired |publisher=Condé Nast |date=19 August 2015}}</ref> Today, other ] of Bitcoin Core exist such as ] and ]. | |||
The proof of work system and the chaining of blocks make blockchain modifications very difficult, as altering one block requires changing all subsequent blocks. As more blocks are added, modifying older blocks becomes increasingly challenging.<ref>{{Cite news |last=Hampton |first=Nikolai |date=5 September 2016 |title=Understanding the blockchain hype: Why much of it is nothing more than snake oil and spin |work=] |url=http://www.computerworld.com.au/article/606253/understanding-blockchain-hype-why-much-it-nothing-more-than-snake-oil-spin/ |url-status=live |access-date=5 September 2016 |archive-url=https://web.archive.org/web/20160906171838/http://www.computerworld.com.au/article/606253/understanding-blockchain-hype-why-much-it-nothing-more-than-snake-oil-spin/ |archive-date=6 September 2016}}</ref><ref name="econbc" /> In case of disagreement, nodes trust the longest chain, which required the greatest amount of effort to produce.<ref name=Mingxiao2017/> To tamper or censor the ledger, one needs to control the majority of the global ].<ref name=Mingxiao2017/> The high cost required to reach this level of computational power ] the bitcoin blockchain.<ref name=Mingxiao2017/> | |||
=== Privacy === | |||
Bitcoin is a pseudonymous currency, meaning that funds are not tied to real-world entities but rather bitcoin addresses. Owners of bitcoin addresses are not explicitly identified, but all transactions on the blockchain are public. In addition, transactions can be linked to individuals and companies through "idioms of use" (e.g., transactions that spend coins from multiple inputs indicate that the inputs may have a common owner) and corroborating public transaction data with known information on owners of certain addresses.<ref>{{cite web |url=http://www.technologyreview.com/news/518816/mapping-the-bitcoin-economy-could-reveal-users-identities/ |title=Mapping the Bitcoin Economy Could Reveal Users’ Identities |work=MIT Technology Review |date=5 September 2013 |accessdate=2 April 2014 |author=Simonite, Tom}}</ref> Additionally, bitcoin exchanges, where bitcoins are traded for traditional currencies, may be required by law to collect personal information.<ref name="5facts">{{cite news |url=http://www.washingtonpost.com/blogs/the-switch/wp/2013/08/21/five-surprising-facts-about-bitcoin-2/ |title=Five surprising facts about Bitcoin |publisher=The Washington Post |date=21 August 2013 |accessdate=2 April 2014 |author=Lee, Timothy}}</ref> | |||
] is controversial and has attracted the attention of regulators, ].<ref name=Stoll2023>{{Cite report |url=https://www.jstor.org/stable/resrep51839 |title=Climate Impacts of Bitcoin Mining in the U.S. |last1=Stoll |first1=Christian |last2=Klaaßen |first2=Lena |date=June 2023 |publisher=MIT Center for Energy and Environmental Policy Research |last3=Gallersdörfer |first3=Ulrich |last4=Neumüller |first4=Alexander |series=Working Paper Series |access-date=24 November 2023 |archive-date=18 November 2023 |archive-url=https://web.archive.org/web/20231118132421/https://www.jstor.org/stable/resrep51839 |url-status=live }}</ref> {{As of|2022}}, a ] study by the ] (CCAF) estimated that bitcoin mining represented {{sigfig|0.38|1}}% of ].<ref name=Messina2023>{{Cite web |last=Messina |first=Irene |date=31 August 2023 |title=Bitcoin electricity consumption: an improved assessment |url=https://www.jbs.cam.ac.uk/2023/bitcoin-electricity-consumption |access-date=7 September 2023 |website=] |language=en-GB |archive-date=7 September 2023 |archive-url=https://web.archive.org/web/20230907181818/https://www.jbs.cam.ac.uk/2023/bitcoin-electricity-consumption/ |url-status=live }}</ref> Another 2022 non-peer-reviewed commentary published in '']'' estimated that bitcoin mining was responsible for {{sigfig|0.19|1}}% of world greenhouse gas emissions.<ref name= deVries2022>{{Cite journal |last1=de Vries |first1=Alex |last2=Gallersdörfer |first2=Ulrich |last3=Klaaßen |first3=Lena |last4=Stoll |first4=Christian |date=16 March 2022 |title=Revisiting Bitcoin's carbon footprint |journal=] |volume=6 |issue=3 |page=499 |doi=10.1016/j.joule.2022.02.005 |s2cid=247143939 |issn=2542-4351|doi-access=free |bibcode=2022Joule...6..498D }}</ref> About half of the electricity used is generated through ]s.<ref name=NYT20220116>{{Cite news |last1=Huang |first1=Jon |last2=O'Neill |first2=Claire |last3=Tabuchi |first3=Hiroko |date=3 September 2021 |title=Bitcoin Uses More Electricity Than Many Countries. How Is That Possible? |work=] |url=https://www.nytimes.com/interactive/2021/09/03/climate/bitcoin-carbon-footprint-electricity.html |issn=0362-4331 |access-date=16 January 2022 |archive-date=17 February 2023 |archive-url=https://web.archive.org/web/20230217105559/https://www.nytimes.com/interactive/2021/09/03/climate/bitcoin-carbon-footprint-electricity.html |url-status=live }}</ref> Moreover, mining hardware's short lifespan results in ].<ref name=deVries2021/> The amount of electrical energy consumed, and the e-waste generated, is comparable to that of Greece and the Netherlands, respectively.<ref name=deVries2021>{{Cite journal |last1=de Vries |first1=Alex |last2=Stoll |first2=Christian |date=December 2021 |title=Bitcoin's growing e-waste problem |url=https://www.sciencedirect.com/science/article/pii/S0921344921005103 |journal=Resources, Conservation and Recycling |volume=175 |page=105901 |doi=10.1016/j.resconrec.2021.105901 |bibcode=2021RCR...17505901D |s2cid=240585651 |issn=0921-3449 |access-date=24 November 2023 |archive-date=23 November 2021 |archive-url=https://web.archive.org/web/20211123145025/https://www.sciencedirect.com/science/article/abs/pii/S0921344921005103 |url-status=live }}</ref><ref name= deVries2022/> | |||
To heighten financial privacy, a new bitcoin address can be generated for each transaction.<ref>{{cite web |url=http://www.wired.co.uk/news/archive/2013-06/06/bitcoin-retail |title=How Bitcoin lets you spy on careless companies |publisher=Conde Nast |work=wired.co.uk |date=6 June 2013 |accessdate=2 April 2014 |author=McMillan, Robert}}</ref> For example, hierarchical deterministic wallets generate ] "rolling addresses" for every transaction from a single ], while only requiring a single passphrase to be remembered to recover all corresponding private keys.<ref>{{cite web |url=https://airbitz.co/go/mastering-bitcoin-privacy/ |title=Mastering Bitcoin Privacy |publisher=Airbitz |date=31 July 2015 |accessdate=23 February 2016 |author=Potts, Jake}}</ref> Additionally, "mixing" and ] services aggregate multiple users' coins and output them to fresh addresses to increase privacy.<ref>{{cite news |url=http://www.forbes.com/sites/jonmatonis/2013/06/05/the-politics-of-bitcoin-mixing-services/ |title=The Politics Of Bitcoin Mixing Services |publisher=Forbes |work=forbes.com |date=5 June 2013 |accessdate=2 April 2014 |author=Matonis, Jon}}</ref> Researchers at ] and ] have also shown that bitcoin exchanges and other entities can prove assets, ], and ] without revealing their addresses using ]s.<ref>{{cite web |url=https://eprint.iacr.org/2015/1008.pdf |title=Provisions: Privacy-preserving proofs of solvency for Bitcoin exchanges |publisher=] |date=26 October 2015 |accessdate=23 February 2016 |authors=Gaby G. Dagher, Benedikt Bünz, Joseph Bonneau, Jeremy Clark and ]}}</ref> | |||
===Privacy and fungibility=== | |||
According to Dan Blystone, "Ultimately, bitcoin resembles cash as much as it does credit cards."<ref>{{cite web |last1=Blystone |first1=Dan |title=Bitcoin Transactions Vs. Credit Card Transactions |url=http://www.investopedia.com/articles/forex/042215/bitcoin-transactions-vs-credit-card-transactions.asp |website=Investopedia |accessdate=3 September 2016}}</ref> | |||
Bitcoin is ]ous, with funds linked to addresses, not real-world identities. While the owners of these addresses are not directly identified, all transactions are public on the blockchain. Patterns of use, like spending coins from multiple inputs, can hint at a common owner. Public data can sometimes be matched with known address owners.<ref>{{cite news |last=Simonite |first=Tom |date=5 September 2013 |title=Mapping the Bitcoin Economy Could Reveal Users' Identities |url=https://www.technologyreview.com/2013/09/05/176558/mapping-the-bitcoin-economy-could-reveal-users-identities/ |access-date=2 April 2014 |work=] |archive-date=27 September 2020 |archive-url=https://web.archive.org/web/20200927062235/https://www.technologyreview.com/2013/09/05/176558/mapping-the-bitcoin-economy-could-reveal-users-identities/ |url-status=live }}</ref> ] might also need to collect personal data as per legal requirements.<ref>{{Cite news |last=Lee, Timothy |date=21 August 2013 |title=Five surprising facts about Bitcoin |newspaper=The Washington Post |url=https://www.washingtonpost.com/news/the-switch/wp/2013/08/21/five-surprising-facts-about-bitcoin-2 |access-date=21 November 2023 |archive-date=9 July 2022 |archive-url=https://web.archive.org/web/20220709135222/https://www.washingtonpost.com/news/the-switch/wp/2013/08/21/five-surprising-facts-about-bitcoin-2/ |url-status=live }}</ref> For enhanced ], users can generate a new address for each transaction.<ref>{{Cite magazine |last=McMillan, Robert |date=6 June 2013 |title=How Bitcoin lets you spy on careless companies |url=https://www.wired.com/2013/06/bitcoin-retai/ |url-status=live |archive-url=https://web.archive.org/web/20140209202222/http://www.wired.co.uk/news/archive/2013-06/06/bitcoin-retail |archive-date=9 February 2014 |access-date=3 April 2020 |magazine=] }}</ref> | |||
In the bitcoin network, each bitcoin is treated equally, ensuring basic ]. However, users and applications can choose to differentiate between bitcoins. While wallets and software treat all bitcoins the same, each bitcoin's transaction history is recorded on the blockchain. This public record allows for ], where users can identify and potentially reject bitcoins from controversial sources.<ref>{{Cite book |last1=Anderson |first1=Ross |last2=Shumailov |first2=Ilia |last3=Ahmed |first3=Mansoor |title=Security Protocols XXVI |chapter=Making Bitcoin Legal |series=Lecture Notes in Computer Science |date=24 November 2018 |volume=11286 |chapter-url=https://www.research.ed.ac.uk/en/publications/making-bitcoin-legal |language=en |publisher=Springer |pages=243–253 |doi=10.1007/978-3-030-03251-7_29 |isbn=978-3-030-03250-0 |editor-last=Matyáš |editor-first=Vashek |editor2-last=Švenda |editor2-first=Petr |editor3-last=Stajano |editor3-first=Frank |editor4-last=Christianson |editor4-first=Bruce |access-date=24 November 2023 |archive-date=24 November 2023 |archive-url=https://web.archive.org/web/20231124165246/https://www.research.ed.ac.uk/en/publications/making-bitcoin-legal |url-status=live }}</ref> For example, in 2012, Mt. Gox froze accounts containing bitcoins identified as stolen.<ref>{{Cite conference |last1=Möser |first1=Malte |last2=Böhme |first2=Rainer |last3=Breuker |first3=Dominic |year=2013 |title=An Inquiry into Money Laundering Tools in the Bitcoin Ecosystem |url=https://maltemoeser.de/paper/money-laundering.pdf |conference=2013 APWG eCrime Researchers Summit |publisher=] |isbn=978-1-4799-1158-5 |archive-url=https://web.archive.org/web/20180626110754/https://maltemoeser.de/paper/money-laundering.pdf |archive-date=26 June 2018 |access-date=19 June 2019 |url-status=live}}</ref> | |||
=== Fungibility === | |||
Wallets and similar software technically handle all bitcoins as equivalent, establishing the basic level of ]. Researchers have pointed out that the history of each bitcoin is registered and publicly available in the blockchain ledger, and that some users may refuse to accept bitcoins coming from controversial transactions, which would harm bitcoin's fungibility.<ref>{{cite web |first1=Eli |last1=Ben-Sasson |first2=Alessandro |last2=Chiesa |first3=Christina |last3=Garman |first4=Matthew |last4=Green |first5=Ian |last5=Miers |first6=Eran |last6=Tromer |first7=Madars |last7=Virza |work=2014 IEEE Symposium on Security and Privacy |title=Zerocash: Decentralized Anonymous Payments from Bitcoin |url=http://zerocash-project.org/media/pdf/zerocash-oakland2014.pdf |date=2014 |accessdate=31 October 2014 |publisher=IEEE computer society}}</ref> Projects such as ] and ] aim to address these privacy and fungibility issues.<ref>{{cite web |last1=Miers |first1=Ian |last2=Garman |first2=Christina |last3=Green |first3=Matthew |last4=Rubin |first4=Aviel |title=Zerocoin: Anonymous Distributed E-Cash from Bitcoin |url=http://isi.jhu.edu/~mgreen/ZerocoinOakland.pdf |publisher=Johns Hopkins University |accessdate=15 February 2015}}</ref><ref>{{cite news |last1=Greenberg |first1=Andy |title=‘Dark Wallet’ Is About to Make Bitcoin Money Laundering Easier Than Ever |url=http://www.wired.com/2014/04/dark-wallet/ |accessdate=15 February 2015 |work=Wired |date=29 April 2014}}</ref> | |||
== |
===Wallets=== | ||
{{Broader|Cryptocurrency wallet}} | |||
{{Main article|History of bitcoin}} | |||
{{multiple image | |||
] | |||
| total_width = 600 | |||
] | |||
| align = center | |||
Bitcoin was created<ref name="NY2011" /> by ],{{r|whoissn}} who published the invention<ref name="NY2011" /> on 31 October 2008{{r|ageofcr}} in a research paper called "Bitcoin: A Peer-to-Peer Electronic Cash System".{{r|paper}} It was implemented as ] and released in January 2009.<ref name="NY2011" /> Bitcoin is often called the first ]<ref name="f_c1" /><ref name="f_c2" /><ref name="f_c3" /> although prior systems existed.<ref group="note" name="prior" /> Bitcoin is more correctly described as the first decentralized ].<ref name="primer" /><ref name="Reuters101" /> | |||
| image1 = Bitcoin-core-v0.10.0.png | |||
| caption1 = Screenshot of ] | |||
| image2 = Sample Bitcoin paper wallet.png | |||
| caption2 = A paper wallet with the address as a ] while the private key is hidden | |||
| image3 = 10elqpi.jpg | |||
| caption3 = A hardware wallet which processes bitcoin transactions without exposing private keys | |||
}} | |||
Bitcoin wallets were the first ]s, enabling users to store the information necessary to transact bitcoins.<ref>{{cite news |first1=Adam |last1=Serwer |first2=Dana|last2= Liebelson |date=10 April 2013 |title=Bitcoin, Explained |url=https://www.motherjones.com/politics/2013/04/what-is-bitcoin-explained |url-status=live |archive-url=https://web.archive.org/web/20140427022315/https://www.motherjones.com/politics/2013/04/what-is-bitcoin-explained |archive-date=27 April 2014 |access-date=26 April 2014 |work=]}}</ref>{{r|Antonopoulos2014|p=ch. 1, glossary}} The first wallet program, simply named ''Bitcoin'', and sometimes referred to as the ''Satoshi client'', was released in 2009 by Nakamoto as ].<ref name="NY2011" /> ] is among the best known ]. ] of Bitcoin Core exist such as ].<ref>{{Cite news |last=Vigna |first=Paul |date=17 January 2016 |title=Is Bitcoin Breaking Up? |work=The Wall Street Journal |url=https://www.wsj.com/articles/is-bitcoin-breaking-up-1453044493 |url-status=live |access-date=8 November 2016 |archive-url=https://web.archive.org/web/20160820144312/http://www.wsj.com/articles/is-bitcoin-breaking-up-1453044493 |archive-date=20 August 2016}}</ref> Wallets can be full clients, with a full copy of the blockchain to check the validity of mined blocks,{{r|Antonopoulos2014|p=ch. 1}} or lightweight clients, just to send and receive transactions without a local copy of the entire blockchain.<ref>{{Cite book |last1=Gervais |first1=Arthur |last2=Capkun |first2=Srdjan |last3=Karame |first3=Ghassan O. |last4=Gruber |first4=Damian |title=Proceedings of the 30th Annual Computer Security Applications Conference |chapter=On the privacy provisions of Bloom filters in lightweight bitcoin clients |date=8 December 2014 |chapter-url=https://doi.org/10.1145/2664243.2664267 |series=ACSAC '14 |location=New York, NY, USA |publisher=Association for Computing Machinery |pages=326–335 |doi=10.1145/2664243.2664267 |isbn=978-1-4503-3005-3 |s2cid=9161497 |access-date=22 November 2023 |archive-date=21 April 2024 |archive-url=https://web.archive.org/web/20240421113526/https://consent.cookiebot.com/uc.js |url-status=live }}</ref> Third-party internet services, called online wallets or hot wallets, store users' credentials on their servers, making them susceptible of hacks.<ref>{{Cite news |first=Bill |last=Barhydt |date=4 June 2014 |title=3 reasons Wall Street can't stay away from bitcoin |publisher=CNBC |url=https://www.cnbc.com/2014/06/04/3-reasons-wall-street-cant-stay-away-from-bitcoin.html |access-date=22 November 2023 |archive-date=4 December 2023 |archive-url=https://web.archive.org/web/20231204140256/https://www.cnbc.com/2014/06/04/3-reasons-wall-street-cant-stay-away-from-bitcoin.html |url-status=live }}</ref> Cold storage protects bitcoins from such hacks by keeping private keys offline, either through specialized hardware wallets or paper printouts.<ref>{{Cite news |last=Roberts |first=Daniel |date=15 December 2017 |title=How to send bitcoin to a hardware wallet |work=Yahoo Finance |url=https://finance.yahoo.com/news/send-bitcoin-hardware-wallet-140141385.html |url-status=live |access-date=17 February 2018 |archive-url=https://web.archive.org/web/20180217142235/https://finance.yahoo.com/news/send-bitcoin-hardware-wallet-140141385.html |archive-date=17 February 2018}}</ref><ref name="Antonopoulos2014" />{{rp|ch. 4}} | |||
=== Scalability and decentralization challenges === | |||
One of the first supporters, adopters, contributor to bitcoin and receiver of the first bitcoin transaction was programmer ]. Finney downloaded the bitcoin software the day it was released, and received 10 bitcoins from Nakamoto in the world's first bitcoin transaction.<ref>{{Cite news |url=http://www.washingtonpost.com/blogs/the-switch/wp/2014/01/03/hal-finney-received-the-first-bitcoin-transaction-heres-how-he-describes-it/ |title=Hal Finney received the first Bitcoin transaction. Here's how he describes it. |last=Peterson |first=Andrea |work=The Washington Post|access-date = |date=3 January 2014}}</ref><ref>{{cite news |last1=Popper |first1=Nathaniel |title=Hal Finney, Cryptographer and Bitcoin Pioneer, Dies at 58 |url=http://www.nytimes.com/2014/08/31/business/hal-finney-cryptographer-and-bitcoin-pioneer-dies-at-58.html?_r=1 |accessdate=2 September 2014 |work=NYTimes |date=30 August 2014}}</ref> Other early supporters were Wei Dai, creator of bitcoin predecessor ''b-money'', and ], creator of bitcoin predecessor ''bit gold''.<ref name="WallaceWired11">{{cite news |url=http://www.wired.com/magazine/2011/11/mf_bitcoin/ |title=The Rise and Fall of Bitcoin |work=Wired |date=23 November 2011 |accessdate=4 November 2013 |author=Wallace, Benjamin}}</ref> | |||
Nakamoto limited the block size to one ].<ref>{{Cite news |last=Mike Orcutt |date=19 May 2015 |title=Leaderless Bitcoin Struggles to Make Its Most Crucial Decision |work=MIT Technology Review |url=https://www.technologyreview.com/s/537486/leaderless-bitcoin-struggles-to-make-its-most-crucial-decision/ |access-date=15 November 2016 |archive-date=18 October 2017 |archive-url=https://wayback.archive-it.org/all/20171018075515/https://www.technologyreview.com/s/537486/leaderless-bitcoin-struggles-to-make-its-most-crucial-decision/ |url-status=live }}</ref> The limited block size and frequency can lead to delayed processing of transactions, increased fees and a ].<ref>{{Cite news |last=Orcutt |first=Mike |date=19 May 2015 |title=Leaderless Bitcoin Struggles to Make Its Most Crucial Decision |work=MIT Technology Review |url=https://www.technologyreview.com/s/537486/leaderless-bitcoin-struggles-to-make-its-most-crucial-decision/ |url-status=live |access-date=22 June 2017 |archive-url=https://wayback.archive-it.org/all/20171018075515/https://www.technologyreview.com/s/537486/leaderless-bitcoin-struggles-to-make-its-most-crucial-decision/ |archive-date=18 October 2017}}</ref> The ], ] ] network, is a potential scaling solution.<ref name="Antonopoulos2014"/>{{rp|ch. 8}} | |||
Research shows a trend towards centralization in bitcoin as miners join ] for stable income.<ref name="JEP">{{Cite journal |last1=Rainer Böhme |last2=Nicolas Christin |last3=Benjamin Edelman |last4=Tyler Moore |year=2015 |title=Bitcoin: Economics, Technology, and Governance |journal=] |volume=29 |issue=2 |pages=213–238 |doi=10.1257/jep.29.2.213 |doi-access=free |issn=0895-3309}}</ref>{{rp|215, 219–222}}<ref>{{Cite journal |last1=Tschorsch |first1=Florian |last2=Scheuermann |first2=Björn |year=2016 |title=Bitcoin and Beyond: A Technical Survey on Decentralized Digital Currencies |journal=] |volume=18 |issue=3 |pages=2084–2123 |doi=10.1109/comst.2016.2535718 |s2cid=5115101}}</ref>{{rp|3}} If a single miner or pool controls more than 50% of the ], it would allow them to censor transactions and double-spend coins.<ref name=Gervais2014/> In 2014, mining pool ] reached 51% mining power, causing safety concerns, but later voluntarily capped its power at 39.99% for the benefit of the whole network.<ref>{{Cite news |last=Wilhelm |first=Alex |title=Popular Bitcoin Mining Pool Promises To Restrict Its Compute Power To Prevent Feared '51%' Fiasco |work=TechCrunch |url=https://techcrunch.com/2014/07/16/popular-bitcoin-mining-pool-promises-to-restrict-its-compute-power-to-prevent-feared-51-fiasco/ |url-status=live |access-date=25 January 2018 |archive-url=https://web.archive.org/web/20171205042008/https://techcrunch.com/2014/07/16/popular-bitcoin-mining-pool-promises-to-restrict-its-compute-power-to-prevent-feared-51-fiasco/ |archive-date=5 December 2017}}</ref> A few entities also dominate other parts of the ecosystem such as the client software, online wallets, and simplified payment verification (SPV) clients.<ref name=Gervais2014/> | |||
In the early days, Nakamoto is estimated to have mined 1 million bitcoins.<ref>{{cite news|last1=McMillan|first1=Robert|title=Who Owns the World's Biggest Bitcoin Wallet? The FBI|url=https://www.wired.com/2013/12/fbi_wallet/|accessdate=7 October 2016|work=Wired|publisher=Condé Nast}}</ref> Before disappearing from any involvement in bitcoin, Nakamoto in a sense handed over the reins to developer ], who then became the bitcoin lead developer at the ], the 'anarchic' bitcoin community's closest thing to an official public face.<ref>{{cite news|last1=Bosker|first1=Bianca|title=Gavin Andresen, Bitcoin Architect: Meet The Man Bringing You Bitcoin (And Getting Paid In It)|url=http://www.huffingtonpost.com/2013/04/16/gavin-andresen-bitcoin_n_3093316.html|accessdate=21 October 2016|work=The Huffington Post|date=16 April 2013}}</ref> | |||
==Economics and usage== | |||
Based on bitcoin's open source code, other cryptocurrencies started to emerge in 2011.<ref name="WsjVolatile" /> | |||
{{Main|Economics of bitcoin}} | |||
===Bitcoin's theoretical roots and ideology=== | |||
In March 2013, a technical glitch caused a fork in the blockchain, with one half of the network adding blocks to one version of the chain and the other half adding to another. For six hours two bitcoin networks operated at the same time, each with its own version of the transaction history. The core developers called for a temporary halt to transactions, sparking a sharp sell-off.<ref name="bug events" /> Normal operation was restored when the majority of the network downgraded to version 0.7 of the bitcoin software.<ref name="bug events">{{cite web |last=Lee |first=Timothy |url=http://arstechnica.com/business/2013/03/major-glitch-in-bitcoin-network-sparks-sell-off-price-temporarily-falls-23/ |title=Major glitch in Bitcoin network sparks sell-off; price temporarily falls 23% |publisher=arstechnica.com |date=11 March 2013 |accessdate=15 February 2015}}</ref> | |||
According to the ], the decentralization of money offered by bitcoin has its theoretical roots in the ], especially with ]'s '']'', in which he advocates a complete ] in the production, distribution and management of money to end the monopoly of ].<ref>{{cite book |author=European Central Bank |url=http://www.ecb.europa.eu/pub/pdf/other/virtualcurrencyschemes201210en.pdf |title=Virtual Currency Schemes |year=2012 |publisher=] |isbn=978-92-899-0862-7 |archive-url=https://web.archive.org/web/20121106053452/http://www.ecb.europa.eu/pub/pdf/other/virtualcurrencyschemes201210en.pdf |archive-date=6 November 2012 |url-status=live|oclc=1044382974|doi=10.2866/47380 }}</ref>{{rp|22}} Sociologist ] argues that the essence of the bitcoin ideology is to remove money from social, as well as governmental, control.<ref>{{cite journal |last1=Dodd |first1=Nigel |date=May 2018 |title=The Social Life of Bitcoin |url=https://eprints.lse.ac.uk/69229/1/Dodd_The%20social%20life%20of%20Bitcoin_author_2017%20LSERO.pdf |journal=Theory, Culture & Society |volume=35 |issue=3 |pages=35–56 |doi=10.1177/0263276417746464 |s2cid=51914607 |issn=0263-2764 |authorlink1=Nigel Dodd |access-date=22 November 2023 |archive-date=22 November 2023 |archive-url=https://web.archive.org/web/20231122163925/https://eprints.lse.ac.uk/69229/1/Dodd_The%20social%20life%20of%20Bitcoin_author_2017%20LSERO.pdf |url-status=live }}</ref> '']'' describes bitcoin as "a ] project to create an online version of cash, a way for people to transact without the possibility of interference from malicious governments or banks".<ref name="30082018Economist" /> These philosophical ideas initially attracted ]s and ]s.<ref>{{cite news |last=Feuer |first=Alan |date=14 December 2013 |title=The Bitcoin Ideology |work=The New York Times |url=https://www.nytimes.com/2013/12/15/sunday-review/the-bitcoin-ideology.html |url-status=live |access-date=1 July 2018 |archive-url=https://web.archive.org/web/20180701222302/https://www.nytimes.com/2013/12/15/sunday-review/the-bitcoin-ideology.html |archive-date=1 July 2018}}</ref> Economist ] argues that cryptocurrencies like bitcoin are only used by bank skeptics and criminals.{{r|Krugman}} | |||
=== Recognition as a currency and legal status === | |||
In 2013 some mainstream websites began accepting bitcoins. ] had started in November 2012,<ref>{{cite web |url=http://en.blog.wordpress.com/2012/11/15/pay-another-way-bitcoin/ |title=Pay Another Way: Bitcoin |last=Skelton |first=Andy |date=15 November 2012 |publisher=] |accessdate=24 April 2014}}</ref> followed by ] in April 2013,<ref>{{cite web |url=http://mashable.com/2013/04/17/okcupid-bitcoin/ |title=OKCupid Now Accepts Bitcoin |last=Franceschi-Bicchierai |first=Lorenzo |date=18 April 2013 |publisher=] |accessdate=24 April 2014}}</ref> ]<ref name=tigger /> and ] in January 2014,<ref name=overstock /> ] in June 2014,<ref>{{cite web |url=http://techcrunch.com/2014/06/11/expedia-now-accepts-bitcoin-for-your-crypto-vacations/ |title=Expedia Now Accepts Bitcoin For Your Crypto-Vacations |last=Biggs |first=John |date=11 June 2014 |publisher=] |accessdate=12 June 2014}}</ref> ] and Dell in July 2014,<ref>{{cite web |first=Mike |last=Flacy |title=Dell, Newegg Start Accepting Bitcoin as Payment |publisher=Digital Trends |date=19 July 2014 |url=http://www.digitaltrends.com/web/dell-newegg-start-accepting-bitcoin-payment/#!bv9oFm |accessdate=5 August 2014}}</ref> and ] in December 2014.<ref name="msftaccepts" /> The ], a non-profit group, started accepting bitcoins in January 2011,<ref>{{cite web |url=https://www.eff.org/deeplinks/2011/01/bitcoin-step-toward-censorship-resistant |title=Bitcoin – a Step Toward Censorship-Resistant Digital Currency |publisher=Electronic Frontier Foundation |date=20 January 2011 |accessdate=21 November 2014 |author=Rainey Reitman}}</ref> stopped accepting them in June 2011,<ref>{{cite web |url=https://www.eff.org/deeplinks/2011/06/eff-and-bitcoin |title=EFF and Bitcoin |publisher=Electronic Frontier Foundation |date=20 June 2011 |accessdate=16 April 2014 |author=Cohn, Cindy}}</ref> and began again in May 2013.<ref name="EFF2013">{{cite web |url=https://www.eff.org/deeplinks/2013/05/eff-will-accept-bitcoins-support-digital-liberty |title=EFF Will Accept Bitcoins to Support Digital Liberty |publisher=Electronic Frontier Foundation |date=17 May 2013 |accessdate=27 April 2014 |author1=Cindy Cohn |author2=Peter Eckersley |author3=Rainey Reitman |author4=Seth Schoen |last-author-amp=yes}}</ref> | |||
{{Legal status of bitcoin|300px}} | |||
] serves three purposes: a ], a ], and a ].<ref name="econ315">{{Cite news |date=15 March 2014 |title=Free Exchange. Money from nothing. Chronic deflation may keep Bitcoin from displacing its rivals. |newspaper=The Economist |url=https://www.economist.com/news/finance-and-economics/21599053-chronic-deflation-may-keep-bitcoin-displacing-its-fiat-rivals-money |url-status=live |access-date=25 March 2014 |archive-url=https://web.archive.org/web/20140325085119/http://www.economist.com/news/finance-and-economics/21599053-chronic-deflation-may-keep-bitcoin-displacing-its-fiat-rivals-money |archive-date=25 March 2014}}</ref> According to ''The Economist'' in 2014, bitcoin functions best as a medium of exchange.<ref name=econ315 /> In 2015, ''The Economist'' noted that bitcoins had three qualities useful in a currency: they are "hard to earn, limited in supply and easy to verify".<ref>{{Cite news |date=13 January 2015 |title=The magic of mining |newspaper=] |url=https://www.economist.com/news/business/21638124-minting-digital-currency-has-become-big-ruthlessly-competitive-business-magic |url-status=live |access-date=13 January 2015 |archive-url=https://web.archive.org/web/20150112165531/http://www.economist.com/news/business/21638124-minting-digital-currency-has-become-big-ruthlessly-competitive-business-magic |archive-date=12 January 2015}}</ref> However, a 2018 assessment by ''The Economist'' stated that cryptocurrencies met none of these three criteria.<ref name="30082018Economist">{{Cite news |date=30 August 2018 |title=Bitcoin and other cryptocurrencies are useless |newspaper=The Economist |url=https://www.economist.com/leaders/2018/08/30/bitcoin-and-other-cryptocurrencies-are-useless |url-status=live |access-date=4 September 2018 |archive-url=https://web.archive.org/web/20180904040905/https://www.economist.com/leaders/2018/08/30/bitcoin-and-other-cryptocurrencies-are-useless |archive-date=4 September 2018 }}</ref> Per some researchers, {{as of|2015|lc=yes}}, bitcoin functions more as a ] than as a currency.<ref name=JEP/> In 2014, economist ] wrote that bitcoin has potential as a unit of account for measuring the relative value of goods, as with Chile's ], but that "Bitcoin in its present form... doesn't really solve any sensible economic problem".<ref name="Shiller">{{Cite news |last=Shiller |first=Robert |date=1 March 2014 |title=In Search of a Stable Electronic Currency |work=The New York Times |url=https://www.nytimes.com/2014/03/02/business/in-search-of-a-stable-electronic-currency.html |url-status=live |archive-url=https://web.archive.org/web/20141024120222/http://www.nytimes.com/2014/03/02/business/in-search-of-a-stable-electronic-currency.html |archive-date=24 October 2014}}</ref> François R. Velde, Senior Economist at the ], described bitcoin as "an elegant solution to the problem of creating a digital currency".<ref>{{cite web |last=Velde |first=François |date=December 2013 |title=Bitcoin: A primer |url=https://www.chicagofed.org/digital_assets/publications/chicago_fed_letter/2013/cfldecember2013_317.pdf |url-status=live |archive-url=https://web.archive.org/web/20141026065254/http://www.chicagofed.org/digital_assets/publications/chicago_fed_letter/2013/cfldecember2013_317.pdf |archive-date=26 October 2014 |access-date=3 September 2016 |website=Chicago Fed letter |publisher=] |page=4 |issue=317}}</ref> David Andolfatto, Vice President at the ], stated that bitcoin is a threat to the establishment, which he argues is a good thing for the ] and other ]s, because it prompts these institutions to operate sound policies.<ref>{{cite news |last=Wile|first= Rob |date=6 April 2014 |title=St. Louis Fed Economist: Bitcoin Could Be A Good Threat To Central Banks |url=http://www.businessinsider.com/interview-with-david-andolfatto-2014-4 |url-status=live |archive-url=https://web.archive.org/web/20150924095030/http://www.businessinsider.com/interview-with-david-andolfatto-2014-4 |archive-date=24 September 2015 |access-date=16 April 2014 |work=]}}</ref> | |||
The ] varies substantially from one jurisdiction to another. Because of its decentralized nature and its global presence, regulating bitcoin is difficult. However, the use of bitcoin can be criminalized, and shutting down exchanges and the peer-to-peer economy in a given country would constitute a ] ban.<ref>{{cite news |first=Jacob |last=Weindling |date=18 September 2017 |title=China May Be Gearing Up to Ban Bitcoin |url=https://www.pastemagazine.com/politics/bitcoin/china-may-be-gearing-up-to-ban-bitcoin |work=] |access-date=22 November 2023 |archive-date=22 November 2023 |archive-url=https://web.archive.org/web/20231122163924/https://www.pastemagazine.com/politics/bitcoin/china-may-be-gearing-up-to-ban-bitcoin |url-status=live }}</ref> The ] has attracted the attention of financial regulators, legislative bodies, and law enforcement.<ref>{{Cite news |last=Lavin|first= Tim |date=8 August 2013 |title=The SEC Shows Why Bitcoin Is Doomed |work=] |url=http://www.bloombergview.com/articles/2013-08-08/did-the-sec-just-validate-bitcoin-no- |url-status=live |access-date=20 October 2013 |archive-url=https://web.archive.org/web/20140325214514/http://www.bloombergview.com/articles/2013-08-08/did-the-sec-just-validate-bitcoin-no- |archive-date=25 March 2014}}</ref> Nobel-prize winning economist ] says that bitcoin's anonymity encourages ] and other crimes.<ref>{{Cite news |last=Montag |first=Ali |date=9 July 2018 |title=Nobel-winning economist: Authorities will bring down 'hammer' on bitcoin |publisher=CNBC |url=https://www.cnbc.com/2018/07/09/nobel-prize-winning-economist-joseph-stiglitz-criticizes-bitcoin.html |url-status=live |access-date=11 July 2018 |archive-url=https://web.archive.org/web/20180711200915/https://www.cnbc.com/2018/07/09/nobel-prize-winning-economist-joseph-stiglitz-criticizes-bitcoin.html |archive-date=11 July 2018}}</ref> This is the main justification behind bitcoin bans.<ref name=SunYin2019/> {{As of|2021|11}}, nine countries applied an absolute ban (Algeria, Bangladesh, China, Egypt, Iraq, Morocco, Nepal, Qatar, and Tunisia) while another 42 countries had an implicit ban.<ref name=LOC2021>{{cite web |title=Regulation of Cryptocurrency Around the World: November 2021 Update |url=https://tile.loc.gov/storage-services/service/ll/llglrd/2021687419/2021687419.pdf |publisher=United States Library of Congress |access-date=28 December 2022 |archive-date=24 December 2021 |archive-url=https://web.archive.org/web/20211224043203/https://tile.loc.gov/storage-services/service/ll/llglrd/2021687419/2021687419.pdf |url-status=live }}</ref>{{Update inline|reason=Many things have changed since Nov 2021.|date=November 2023}} Bitcoin is only ] in ].<ref name=BTCSVSept7FT/> | |||
In May 2013, the ] seized assets belonging to the Mt. Gox exchange.<ref>{{cite news |last=Dillet |first=Romain |title=Feds Seize Assets From Mt. Gox's Dwolla Account, Accuse It Of Violating Money Transfer Regulations |url=http://techcrunch.com/2013/05/16/mt-gox-dwolla-account-money-seizure/ |work=TechCrunch |date=16 May 2013 |accessdate=15 May 2013}}</ref> The U.S. ] (FBI) shut down the ] website in October 2013.<ref>{{cite news |url=http://www.bloomberg.com/news/2013-10-03/fbi-snags-silk-road-boss-with-own-methods.html |title=FBI Snags Silk Road Boss With Own Methods |work=Bloomberg |location=New York |date=3 October 2013 |accessdate=27 October 2013 |author=Farrell, Greg}}</ref> | |||
=== Use for payments === | |||
In October 2013, Chinese internet giant ] had allowed clients of website security services to pay with bitcoins.<ref>{{cite web |url=http://www.businessinsider.com/chinas-google-is-now-accepting-bitcoin-2013-10 |title=China's Google Is Now Accepting Bitcoin |publisher=Business Insider, Inc |work=businessinsider.com |date=15 October 2013 |accessdate=26 December 2013 |author=Kapur, Saranya}}</ref> During November 2013, the China-based bitcoin exchange ] overtook the Japan-based Mt. Gox and the Europe-based ] to become the largest bitcoin trading exchange by trade volume.<ref>{{cite web |url=http://techcrunch.com/2013/11/18/btc-china-series-a/ |title=As Chinese Investors Pile Into Bitcoin, China's Oldest Exchange, BTC China, Raises $5M From Lightspeed |publisher=TechCrunch |date=18 November 2013 |author=Natasha Lomas |accessdate=10 January 2014}}</ref> On 19 November 2013, the value of a bitcoin on the Mt. Gox exchange soared to a peak of US$900 after a United States Senate committee hearing was told by the FBI that virtual currencies are a legitimate financial service.<ref>{{cite news |url=http://www.bbc.co.uk/news/technology-24986264 |title=BBC News – 'Legitimate' Bitcoin's value soars after Senate hearing |publisher=Bbc.co.uk |date=19 November 2013 |accessdate=10 January 2014}}</ref> On the same day, one bitcoin traded for over ]¥6780 (US$1,100) in China.<ref>{{cite news |url=http://www.zdnet.com/cn/china-no-plans-yet-to-legalize-use-of-bitcoins-7000023512/ |title=China no plans yet to legalize use of Bitcoins |work=ZDNet |date=22 November 2013 |accessdate=27 November 2013 |last=Lee |first=Cyrus}}</ref> On 5 December 2013, the ] prohibited Chinese financial institutions from using bitcoins.<ref name="ccontrols">{{cite news |url=http://www.bbc.co.uk/news/technology-25428866 |title=Bitcoin sinks after China restricts yuan exchanges |publisher=BBC |work=bbc.com |date=18 December 2013 |accessdate=20 December 2013 |author=Kelion, Leo}}</ref> After the announcement, the value of bitcoins dropped,<ref>{{cite news |date=6 December 2013 |url=http://www.smh.com.au/business/markets/currencies/china-bans-banks-from-bitcoin-transactions-20131206-2yugy.html |title=China bans banks from bitcoin transactions |work=] |publisher=Reuters |accessdate=31 October 2014}}</ref> and Baidu no longer accepted bitcoins for certain services.<ref name="bloomberg">{{cite news |url=http://www.bloomberg.com/news/2013-12-07/baidu-stops-accepting-bitcoins-after-china-ban.html |title=Baidu Stops Accepting Bitcoins After China Ban |work=Bloomberg |location=New York |date=7 December 2013 |accessdate=11 December 2013}}</ref> Buying real-world goods with any virtual currency has been illegal in China since at least 2009.<ref>{{cite web |url=http://english.mofcom.gov.cn/aarticle/newsrelease/commonnews/200906/20090606364208.html |title=China bars use of virtual money for trading in real goods |publisher=English.mofcom.gov.cn |date=29 June 2009 |accessdate=10 January 2014}}</ref> | |||
] accepting Bitcoin]] | |||
{{As of|2018}}, bitcoin is rarely used in transactions with merchants,<ref name="FT08062018" /> but it is popular to ] online.<ref name=TheEconomist20120929>{{Cite news |title=Monetarists Anonymous |newspaper=The Economist |url=https://www.economist.com/finance-and-economics/2012/09/29/monetarists-anonymous |date=29 September 2012 |access-date=22 November 2023 |issn=0013-0613 |archive-date=1 September 2022 |archive-url=https://web.archive.org/web/20220901043303/https://www.economist.com/finance-and-economics/2012/09/29/monetarists-anonymous |url-status=live }}</ref><ref>{{Cite news |last=Ball |first=James |date=22 March 2013 |title=Silk Road: the online drug marketplace that officials seem powerless to stop |language=en-GB |work=The Guardian |url=https://www.theguardian.com/world/2013/mar/22/silk-road-online-drug-marketplace |access-date=22 November 2023 |issn=0261-3077 |archive-date=12 October 2013 |archive-url=https://web.archive.org/web/20131012012106/http://www.theguardian.com/world/2013/mar/22/silk-road-online-drug-marketplace |url-status=live }}</ref> Prices are not usually quoted in bitcoin and trades involve conversions into ] currencies.<ref name=JEP/> Commonly cited reasons for not using bitcoin include high costs, the inability to process ]s, high ], long transaction times, and ] (especially for small purchases).<ref name="FT08062018">{{Cite news |last=Murphy |first=Hannah |date=8 June 2018 |title=Who really owns bitcoin now? |work=Financial Times |url=https://www.ft.com/content/29259448-69b3-11e8-b6eb-4acfcfb08c11 |url-status=live |access-date=10 June 2018 |archive-url=https://web.archive.org/web/20180610051316/https://www.ft.com/content/29259448-69b3-11e8-b6eb-4acfcfb08c11 |archive-date=10 June 2018}}</ref><ref>{{cite news |last=Katz |first=Lily |date=12 July 2017 |title=Bitcoin Acceptance Among Retailers Is Low and Getting Lower |url=https://www.bloomberg.com/news/articles/2017-07-12/bitcoin-acceptance-among-retailers-is-low-and-getting-lower |url-status=live |archive-url=https://web.archive.org/web/20180125204553/https://www.bloomberg.com/news/articles/2017-07-12/bitcoin-acceptance-among-retailers-is-low-and-getting-lower |archive-date=25 January 2018 |access-date=25 January 2018 |work=Bloomberg News}}</ref> ''Bloomberg'' reported that bitcoin was being used for large-item purchases on the site ] and for cross-border payments to ]s.<ref>{{Cite news |last=Kharif |first=Olga |date=1 August 2018 |title=Bitcoin's Use in Commerce Keeps Falling Even as Volatility Eases |work=Bloomberg News|url=https://www.bloomberg.com/news/articles/2018-08-01/bitcoin-s-use-in-commerce-keeps-falling-even-as-volatility-eases |url-status=live |access-date=2 August 2018 |archive-url=https://web.archive.org/web/20180802073219/https://www.bloomberg.com/news/articles/2018-08-01/bitcoin-s-use-in-commerce-keeps-falling-even-as-volatility-eases |archive-date=2 August 2018}}</ref> {{As of|2015}}, there was little sign of bitcoin use in international ]s despite high fees charged by banks and ] who compete in this market.<ref name=JEP/><ref>{{Cite news |last=Chan |first=Bernice |date=16 January 2015 |title=Bitcoin transactions cut the cost of international money transfers |work=] |url=https://www.scmp.com/lifestyle/technology/article/1679904/bitcoin-transactions-cut-cost-international-money-transfers |url-status=live |access-date=31 May 2019 |archive-url=https://web.archive.org/web/20190531060301/https://www.scmp.com/lifestyle/technology/article/1679904/bitcoin-transactions-cut-cost-international-money-transfers |archive-date=31 May 2019}}</ref> Despite associated risks and costs, in 2022, a growing use of bitcoin, alongside cash and cards, was reported in restaurant business.<ref>{{Cite web |url=https://www.nbcnews.com/business/bitcoin-bitcoin-restaurants-start-accept-cryptocurrencies-rcna21211 |title=Bitcoin by bitcoin, restaurants start to accept cryptocurrencies |date=2022-04-11 |access-date=2024-10-07 |website=NBC News |last=Sheidlower |first=Noah}}</ref> | |||
In September 2021, the ] made bitcoin ] in ], alongside the US dollar.<ref name=BTCSVSept7FT/> The adoption has been criticized internationally and within El Salvador.<ref name=BTCSVSept7FT/><ref>{{cite news |date=2 September 2021 |title=Majority of Salvadorans do not want bitcoin, poll shows |url=https://www.reuters.com/technology/majority-salvadorans-do-not-want-bitcoin-poll-shows-2021-09-02/ |access-date=30 November 2021 |work=Reuters |archive-date=30 November 2021 |archive-url=https://web.archive.org/web/20211130154620/https://www.reuters.com/technology/majority-salvadorans-do-not-want-bitcoin-poll-shows-2021-09-02/ |url-status=live }}</ref> In 2022, the ] (IMF) urged El Salvador to reverse its decision.<ref>{{cite news |date=26 January 2022 |title=IMF urges El Salvador to remove Bitcoin as legal tender |work=BBC News |url=https://www.bbc.co.uk/news/world-latin-america-60135552 |access-date=26 January 2022 |archive-date=26 January 2022 |archive-url=https://web.archive.org/web/20220126154241/https://www.bbc.co.uk/news/world-latin-america-60135552 |url-status=live }}</ref> {{As of|2022}}, the use of ] remains low: 80% of businesses refused to accept it.<ref>{{cite report |title=Are Cryptocurrencies Currencies? Bitcoin as Legal Tender in El Salvador |last1=Alvarez |first1=Fernando |last2=Argente |first2=David |publisher=National Bureau of Economic Research |doi=10.3386/w29968 |page= |last3=Van Patten |first3=Diana |doi-access=free |publication-place=Cambridge, MA |year=2022}}</ref> In April 2022, the ] (CAR) adopted bitcoin as legal tender alongside the ],<ref>{{Cite news |date=28 April 2022 |title=Bitcoin Declared Legal Currency in Central African Republic |work=Bloomberg |url=https://www.bloomberg.com/news/articles/2022-04-28/bitcoin-is-declared-a-legal-currency-in-central-african-republic-l2isppnb |access-date=28 April 2022 |archive-date=28 April 2022 |archive-url=https://web.archive.org/web/20220428141222/https://www.bloomberg.com/news/articles/2022-04-28/bitcoin-is-declared-a-legal-currency-in-central-african-republic-l2isppnb |url-status=live }}</ref> but repealed the reform one year later.<ref>{{Cite web |title=Frequently Asked Questions on Central African Republic |url=https://www.imf.org/en/Countries/CAF/central-african-republic-qandas |access-date=11 August 2023 |website=International Monetary Fund |language=en |archive-date=11 August 2023 |archive-url=https://web.archive.org/web/20230811002905/https://www.imf.org/en/Countries/CAF/central-african-republic-qandas |url-status=live }}</ref> | |||
The first ] was installed in October 2013 in Vancouver, British Columbia, Canada.<ref>{{cite news |url=http://www.wired.com/wiredenterprise/2013/10/bitcoin_atm_gallery/ |title=Take a tour of Robocoin, the world's first Bitcoin ATM |first=Robert |last=McMillan |date=29 October 2013 |work=Wired |accessdate=31 October 2014}}</ref> | |||
Bitcoin is also used by some governments. For instance, the ] initially opposed cryptocurrencies, but later saw them as an opportunity to circumvent ].<ref>{{cite news |date=3 November 2020 |title=Iran Is Pivoting to Bitcoin |url=https://www.vice.com/en/article/qjppx3/iran-bitcoin-us-sanctions |work=] |last=Rasool |first=Mohammed |access-date=10 November 2020 |archive-date=3 November 2020 |archive-url=https://web.archive.org/web/20201103235640/https://www.vice.com/en/article/qjppx3/iran-bitcoin-us-sanctions |url-status=live }}</ref> Since 2020, Iran has required local bitcoin miners to sell bitcoin to the ], allowing the central bank to use it for imports.<ref name="aawsat202011">{{cite news |date=31 October 2020 |title=Iran: New Crypto Law Requires Selling Bitcoin Directly to Central Bank to Fund Imports |url=https://english.aawsat.com/home/article/2596686/iran-new-crypto-law-requires-selling-bitcoin-directly-central-bank-fund-imports |work=] |access-date=31 October 2020 |archive-date=31 October 2020 |archive-url=https://web.archive.org/web/20201031235032/https://english.aawsat.com/home/article/2596686/iran-new-crypto-law-requires-selling-bitcoin-directly-central-bank-fund-imports |url-status=live }}</ref> Some ] also accept tax payments in bitcoin, including ] (])<ref>{{Cite news |date=21 September 2022 |title=Colorado accepts cryptocurrency to pay taxes, moving the state "tech forward" |url=https://www.denverpost.com/2022/09/21/colorado-accepts-cryptocurrency-taxes/ |first=Judith |last=Kohler |work=] |language=en-US |access-date=29 December 2022 |archive-date=29 December 2022 |archive-url=https://web.archive.org/web/20221229090417/https://www.denverpost.com/2022/09/21/colorado-accepts-cryptocurrency-taxes/ |url-status=live }}</ref> and ] (]).<ref>{{Cite news |date=3 September 2020 |title='Crypto Valley' canton to accept Bitcoin for tax payments |url=https://www.swissinfo.ch/eng/business/-crypto-valley--canton-to-accept-bitcoin-for-tax-payments/46010364 |work=] |language=en |access-date=22 November 2023 |archive-date=22 November 2023 |archive-url=https://web.archive.org/web/20231122163924/https://www.swissinfo.ch/eng/business/-crypto-valley--canton-to-accept-bitcoin-for-tax-payments/46010364 |url-status=live }}</ref> As of 2023, the US government owned more than $5 billion worth of seized bitcoin.<ref>{{Cite news |last=Huang |first=Vicky Ge |title=Why the U.S. Government Has $5 Billion in Bitcoin |url=https://www.wsj.com/finance/currencies/federal-government-bitcoin-5-billion-78ce0938 |date=15 October 2023 |work=] |language=en-US |access-date=20 February 2024 |archive-date=20 February 2024 |archive-url=https://web.archive.org/web/20240220023509/https://www.wsj.com/finance/currencies/federal-government-bitcoin-5-billion-78ce0938 |url-status=live }}</ref><ref>{{Cite news |last=Castillo |first=Michael del |title=U.S. Government Owns Way More Bitcoin Than Any Other Country–So Why Aren't They Selling It? |url=https://www.forbes.com/sites/michaeldelcastillo/2023/06/16/us-government-owns-way-more-bitcoin-than-any-other-countryso-why-arent-they-selling-it |date=16 June 2023 |website=] |language=en |access-date=21 February 2024 |archive-date=21 February 2024 |archive-url=https://web.archive.org/web/20240221155659/https://www.forbes.com/sites/michaeldelcastillo/2023/06/16/us-government-owns-way-more-bitcoin-than-any-other-countryso-why-arent-they-selling-it/ |url-status=live }}</ref> | |||
With about 12 million existing bitcoins in November 2013,<ref name="raskin">{{cite news |url=http://www.bloomberg.com/news/2013-11-18/u-s-agencies-to-say-bitcoins-offer-legitimate-benefits.html |title=U.S. Agencies to Say Bitcoins Offer Legitimate Benefits |date=18 November 2013 |accessdate=24 November 2013 |first=Max |last=Raskin |work=Bloomberg}}</ref> the new price increased the ] for bitcoin to at least US$7.2 billion.<ref>{{cite web |author=Todd Wasserman |url=http://mashable.com/2013/11/18/bitcoin-600/ |title=Bitcoin Tops $600, Up 60x Over the Last Year |publisher=Mashable.com |date=18 November 2013 |accessdate=10 January 2014}}</ref> By 23 November 2013, the total market capitalization of bitcoin exceeded US$10 billion for the first time.<ref>{{cite web |url=http://blog.panampost.com/joel-fensch/2014/01/02/bitcoin-set-to-boom-in-latin-america/ |title=Bitcoin Set to Boom in Latin America |author=Joel Fensch |publisher=Blog.panampost.com |date=2 January 2014 |accessdate=7 January 2014}}</ref> | |||
===Use for investment and status as an economic bubble === | |||
In the U.S., two men were arrested in January 2014 on charges of money-laundering using bitcoins; one was ], the head of now defunct bitcoin exchange ] and a vice chairman of the ]. Shrem allegedly allowed the other arrested party to purchase large quantities of bitcoins for use on black-market websites.<ref name=vchair /> | |||
{{Further|Cryptocurrency bubble}} | |||
] | |||
{{As of|2018}}, the overwhelming majority of bitcoin transactions took place on ]s.<ref name="FT08062018" /> Since 2014, regulated bitcoin funds also allow ] to the asset or to ] as an investment.<ref>{{Cite news |date=10 July 2014 |title=Jersey approve Bitcoin fund launch on island |work=BBC News |url=https://www.bbc.com/news/world-europe-jersey-28247796 |url-status=live |access-date=10 July 2014 |archive-url=https://web.archive.org/web/20140710211917/http://www.bbc.com/news/world-europe-jersey-28247796 |archive-date=10 July 2014}}</ref><ref>{{Cite news |date=18 December 2017 |title=Chicago Mercantile Exchange jumps into bitcoin futures |work=CBS News |url=https://www.cbsnews.com/news/chicago-mercantile-exchange-jumps-into-bitcoin-futures/ |url-status=live |access-date=31 May 2019 |archive-url=https://web.archive.org/web/20190531054602/https://www.cbsnews.com/news/chicago-mercantile-exchange-jumps-into-bitcoin-futures/ |archive-date=31 May 2019}}</ref> Bitcoin is used as a ]:<ref>{{Cite news |date=2021-10-25 |title=Gold or Bitcoin? Store-of-value debate rages as Bitcoin grows |url=https://www.bloomberg.com/professional/insights/trading/gold-or-bitcoin-store-of-value-debate-rages-as-bitcoin-grows/ |access-date=2024-10-02 |work=Bloomberg Professional Services |language=en-US}}</ref><ref>{{cite news|url=https://www.reuters.com/business/finance/goldman-sachs-says-bitcoin-will-compete-with-gold-store-value-2022-01-05/|title=Goldman Sachs says bitcoin will compete with gold as "store of value"|website=Reuters|date=2022-01-05}}</ref> individuals and companies such as the ]<ref>{{Cite news |last=Lee |first=Timothy B. |title=The $11 million in bitcoins the Winklevoss brothers bought is now worth $32 million |newspaper=The Washington Post |url=https://www.washingtonpost.com/news/the-switch/wp/2013/11/09/the-11-million-in-bitcoins-the-winklevoss-brothers-bought-is-now-worth-32-million/ |url-status=live |access-date=11 August 2017 |archive-url=https://web.archive.org/web/20170706111658/https://www.washingtonpost.com/news/the-switch/wp/2013/11/09/the-11-million-in-bitcoins-the-winklevoss-brothers-bought-is-now-worth-32-million/ |archive-date=6 July 2017}}</ref> and ]'s companies ] and ] have massively invested in bitcoin.<ref>{{cite news |last1=Maidenberg |first1=Micah |last2=Driebusch |first2=Corrie |last3=Jin |first3=Berber |title=A Rare Look Into the Finances of Elon Musk's Secretive SpaceX |url=https://www.wsj.com/tech/behind-the-curtain-of-elon-musks-secretive-spacex-revenue-growth-and-rising-costs-2c828e2b |access-date=19 November 2023 |work=The Wall Street Journal |date=17 August 2023 |url-access=subscription |archive-date=17 August 2023 |archive-url=https://archive.today/20230817224420/https://www.wsj.com/tech/behind-the-curtain-of-elon-musks-secretive-spacex-revenue-growth-and-rising-costs-2c828e2b |url-status=live }}</ref><ref>{{Cite news |last1=Ostroff |first1=Caitlin |last2=Elliott |first2=Rebecca |date=8 February 2021 |title=Tesla Buys $1.5 Billion in Bitcoin |language=en-US |work=] |url=https://www.wsj.com/articles/tesla-buys-1-5-billion-in-bitcoin-11612791688 |access-date=22 November 2023 |issn=0099-9660 |url-access=subscription |archive-date=6 January 2024 |archive-url=https://web.archive.org/web/20240106160013/https://www.wsj.com/articles/tesla-buys-1-5-billion-in-bitcoin-11612791688 |url-status=live }}</ref> Bitcoin wealth is highly concentrated, with 0.01% holding 27% of in-circulation currency, as of 2021.<ref>{{Cite news |last1=Vigna |first1=Paul |title=Bitcoin's 'One Percent' Controls Lion's Share of the Cryptocurrency's Wealth |work=] |date=20 December 2021 |url=https://www.wsj.com/articles/bitcoins-one-percent-controls-lions-share-of-the-cryptocurrencys-wealth-11639996204 |issn=0099-9660 |url-access=subscription |access-date=22 December 2021 |archive-date=22 December 2021 |archive-url=https://web.archive.org/web/20211222180909/https://www.wsj.com/articles/bitcoins-one-percent-controls-lions-share-of-the-cryptocurrencys-wealth-11639996204 |url-status=live }}</ref> {{As of|2023|9}}, El Salvador had $76.5 million worth of bitcoin in its ].<ref>{{Cite news |last=Cota |first=Isabella |date=2 September 2023 |title=Two years of bitcoin in Bukele's El Salvador: An opaque experiment with a little-used currency |url=https://english.elpais.com/international/2023-09-02/two-years-of-bitcoin-in-bukeles-el-salvador-an-opaque-experiment-with-a-little-used-currency.html |website=] |language=en-us |access-date=24 November 2023 |archive-date=24 November 2023 |archive-url=https://web.archive.org/web/20231124082557/https://english.elpais.com/international/2023-09-02/two-years-of-bitcoin-in-bukeles-el-salvador-an-opaque-experiment-with-a-little-used-currency.html |url-status=live }}</ref> | |||
In 2018, research published in the '']'' concluded that ] occurred during the ] bitcoin theft and that the market remained vulnerable to manipulation.<ref>{{cite journal |last1=Gandal |first1=Neil |last2=Hamrick |first2=J.T. |last3=Moore |first3=Tyler |last4=Oberman |first4=Tali |date=May 2018 |title=Price manipulation in the Bitcoin ecosystem |journal=] |volume=95 |pages=86–96 |doi=10.1016/j.jmoneco.2017.12.004 |s2cid=26358036 |doi-access=free}}</ref> Research published in '']'' also suggested that trading associated with increases in the amount of the ] and associated trading at the ] exchange accounted for about half of the price increase in bitcoin in late 2017.<ref>{{Cite journal |last1=Griffin |first1=John M. |last2=Shams |first2=Amin |date=August 2020 |title=Is Bitcoin Really Untethered? |url= |journal=] |language=en |volume=75 |issue=4 |pages=1913–1964 |doi=10.1111/jofi.12903 |doi-access=free|s2cid=229576274 |issn=0022-1082}}</ref><ref>{{Cite news |last=Popper |first=Nathaniel |date=13 June 2018 |title=Bitcoin's Price Was Artificially Inflated Last Year, Researchers Say |work=The New York Times |url=https://www.nytimes.com/2018/06/13/technology/bitcoin-price-manipulation.html |url-status=live |access-date=13 June 2018 |archive-url=https://web.archive.org/web/20180613100732/https://www.nytimes.com/2018/06/13/technology/bitcoin-price-manipulation.html |archive-date=13 June 2018}}</ref> | |||
In early February 2014, one of the largest bitcoin exchanges, ],<ref name="mtgoxdetails">{{cite web |url=http://www.bbc.com/news/technology-26420932 |title=MtGox gives bankruptcy details |publisher=BBC |work=bbc.com |date=4 March 2014 |accessdate=13 March 2014}}</ref> suspended withdrawals citing technical issues.<ref>{{cite web |url=http://techcrunch.com/2014/02/10/whats-going-on-with-bitcoin-exchange-mt-gox/ |title=What's Going On With Bitcoin Exchange Mt. Gox? |first=John |last=Biggs |publisher=TechCrunch |date=10 February 2014 |accessdate=26 February 2014}}</ref> By the end of the month, Mt. Gox had filed for bankruptcy protection in Japan amid reports that 744,000 bitcoins had been stolen.<ref name="GoxBankrupt">{{cite web |url=http://www.bbc.com/news/technology-25233230 |title=MtGox bitcoin exchange files for bankruptcy |publisher=BBC |work=bbc.com |date=28 February 2014 |accessdate=18 April 2014}}</ref> Months before the filing, the popularity of Mt. Gox had waned as users experienced difficulties withdrawing funds.<ref>{{cite web |url=http://www.csmonitor.com/USA/USA-Update/2014/0228/MtGox-bankruptcy-Bitcoin-insiders-saw-problems-with-the-exchange-for-months |title=MtGox bankruptcy: Bitcoin insiders saw problems with the exchange for months |publisher=The Christian Science Monitor |work=csmonitor.com |date=28 February 2014 |accessdate=18 April 2014 |author=Swan, Noelle}}</ref> | |||
Bitcoin, along with other cryptocurrencies, has been described as an ] by several economists, including ] laureates, such as ],<ref name="Stiglitz">{{Cite news |last=Costelloe |first=Kevin |date=29 November 2017 |title=Bitcoin 'Ought to Be Outlawed,' Nobel Prize Winner Stiglitz Says |work=Bloomberg News |url=https://www.bloomberg.com/news/articles/2017-11-29/bitcoin-ought-to-be-outlawed-nobel-prize-winner-stiglitz-says-jal10hxd |url-status=live |access-date=5 June 2018 |archive-url=https://web.archive.org/web/20180612224313/https://www.bloomberg.com/news/articles/2017-11-29/bitcoin-ought-to-be-outlawed-nobel-prize-winner-stiglitz-says-jal10hxd |archive-date=12 June 2018 |quote=It doesn't serve any socially useful function. |url-access=subscription}}</ref> ],<ref name=4Nobels/> and ].<ref name=Krugman>{{Cite news |last=Mohamed |first=Theron |title=Nobel economist Paul Krugman slams crypto as mostly useless, after saying it's hugely overpriced and helps criminals |url=https://markets.businessinsider.com/news/currencies/paul-krugman-crypto-bitcoin-price-bubble-crime-cbdc-desantis-banks-2023-5 |date=30 May 2023 |website=] |language=en-US |access-date=23 November 2023 |archive-date=23 November 2023 |archive-url=https://web.archive.org/web/20231123131322/https://markets.businessinsider.com/news/currencies/paul-krugman-crypto-bitcoin-price-bubble-crime-cbdc-desantis-banks-2023-5 |url-status=live }}</ref> Another recipient of the prize, ], argues that bitcoin is rather a ] that may become an ]. He describes its price growth as an "epidemic", driven by ].<ref>{{Cite news |date=9 June 2021 |title=Don't Call Bitcoin a Bubble. It's an Epidemic |language=en |work=Bloomberg.com |url=https://www.bloomberg.com/opinion/articles/2021-06-09/don-t-call-bitcoin-a-bubble-it-s-an-epidemic |first=John |last=Authers|author-link=John Authers|archive-url=https://web.archive.org/web/20210610021335/https://www.bloomberg.com/opinion/articles/2021-06-09/don-t-call-bitcoin-a-bubble-it-s-an-epidemic |archive-date=10 June 2021 |url-status=live |url-access=subscription}}</ref> In 2024, ], also Nobel laureate, described bitcoin as a "pure bubble" as its ] is zero. According to him, some bubbles are long-lasting such as gold and fiat currencies, and it's impossible to predict whether bitcoin will collapse like other financial bubbles or become the new gold.<ref>{{Cite news |date=2024-02-01 |title=Cryptocurrencies: an economist's view |url=https://www.tse-fr.eu/cryptocurrencies-economists-view |access-date=2024-11-15 |language=en | first1=Jean|last1=Tirole|author-link1=Jean Tirole|work=La Jaune et la Rouge|issue=792|volume=February 2024}}</ref> The same year, ] ] described bitcoin as a digital competitor to gold but not to the dollar as he argued it is a highly volatile ] asset not used as a form of payment.<ref>{{Cite news |author= |date= |title=Bitcoin breaks $100,000 barrier amid post-election cryptocurrency surge |url=https://www.washingtonpost.com/business/2024/12/04/bitcoin-price-100k-crypto-trump/ |access-date=5 December 2024 |newspaper=Washington Post |quote=“People use bitcoin as a speculative asset. It’s like gold, it’s just like gold, only it’s virtual, it’s digital. People are not using it as a form of payment or a store of value,” he said. “It’s highly volatile. It’s not a competitor for the dollar; it’s really a competitor for gold.”}}</ref> | |||
On 18 June 2014, it was announced that bitcoin ] ] would become the new sponsor of ] under a two-year deal, renamed the Bitcoin St. Petersburg Bowl. Bitcoin was to be accepted for ticket and concession sales at the game as part of the sponsorship, and the sponsorship itself was also paid for using bitcoin.<ref name=wsj-bitpay>{{cite news |title=BitPay to Sponsor St. Petersburg Bowl in First Major Bitcoin Sports Deal |url=http://online.wsj.com/articles/bitpay-to-sponsor-st-petersburg-bowl-in-first-major-bitcoin-sports-deal-1403098202 |accessdate=18 June 2014 |work=The Wall Street Journal |first=Michael J. |last=Casey |date=18 June 2014}}</ref> | |||
According to research published in the '']'' in 2018, bitcoin as an asset is highly volatile and does not behave like any other conventional asset.<ref>{{Cite journal |last1=Klein |first1=Tony |last2=Pham Thu |first2=Hien |last3=Walther |first3=Thomas |date=October 2018 |title=Bitcoin is not the New Gold – A comparison of volatility, correlation, and portfolio performance |url=https://pureadmin.qub.ac.uk/ws/files/155247201/crypto_V2.pdf |journal=International Review of Financial Analysis |language=en |volume=59 |pages=105–116 |doi=10.1016/j.irfa.2018.07.010 |s2cid=158400153 |doi-access= |access-date=24 November 2023 |archive-date=25 November 2023 |archive-url=https://web.archive.org/web/20231125164037/https://pureadmin.qub.ac.uk/ws/files/155247201/crypto_V2.pdf |url-status=live }}</ref> According to one 2022 analysis published in '']'', bitcoin was less volatile than ], ], ], and 190 stocks in the ] during and after the ].<ref>{{Cite journal |last=Mazur |first=Mieszko |date=31 March 2022 |title=Misperceptions of Bitcoin Volatility |url= |journal=The Journal of Alternative Investments |language=en |volume=24 |issue=4 |pages=33–44 |doi=10.3905/jai.2022.1.153 |s2cid=247843794 |issn=1520-3255 |doi-access=}}</ref> The term {{wikt-lang|en|hodl}} was created in December 2013 for ] bitcoin rather than selling it during periods of volatility.<ref>{{cite news |last1=Montag |first1=Ali |title='HODL,' 'whale' and 5 other cryptocurrency slang terms explained |url=https://www.cnbc.com/2018/01/23/what-hodl-whale-and-other-cryptocurrency-slang-terms-mean.html |work=CNBC |date=26 August 2018 |access-date=16 March 2021 |archive-date=12 January 2022 |archive-url=https://web.archive.org/web/20220112091630/https://www.cnbc.com/2018/01/23/what-hodl-whale-and-other-cryptocurrency-slang-terms-mean.html |url-status=live }}</ref><ref>{{Cite news |url=https://www.bloomberg.com/news/articles/2020-11-19/what-the-heck-is-hodl-bitcoin-lingo-for-crypto-noobs-quicktake |title=All the Bitcoin Lingo You Need to Know as Crypto Heats Up |last=Hajric |first=Vildana |date=19 November 2020 |work=Bloomberg |access-date=1 December 2020 |url-access=subscription |archive-date=29 November 2020 |archive-url=https://web.archive.org/web/20201129234847/https://www.bloomberg.com/news/articles/2020-11-19/what-the-heck-is-hodl-bitcoin-lingo-for-crypto-noobs-quicktake |url-status=live }}</ref> | |||
Less than one year after the collapse of Mt. Gox, United Kingdom-based exhange ] announced that their exchange would be taken offline while they investigate a hack which resulted in about 19,000 bitcoins (equivalent to roughly US$5 million at that time) being stolen from their hot wallet.<ref>{{cite news |url=http://www.reuters.com/article/2015/01/06/us-bitstamp-cybersecurity-idUSKBN0KF0UH20150106 |title=Bitcoin exchange Bitstamp suspends service after security breach |publisher=Reuters |work=reuters.com |date=6 January 2015 |accessdate=24 January 2015 |author=Srivastava, Shivam}}</ref> The exchange remained offline for several days amid speculation that customers had lost their funds. Bitstamp resumed trading on 9 January after increasing security measures and assuring customers that their account balances would not be impacted.<ref>{{cite news |url=http://www.reuters.com/article/2015/01/09/bitstamp-cybersecurity-idUSL6N0UO1DC20150109 |title=Bitcoin exchange Bitstamp says to resume trading on Friday |publisher=Reuters |work=reuters.com |date=9 January 2015 |accessdate=24 January 2015 |author=Novak, Marja}}</ref> | |||
Other economists, investors, and the ] have described bitcoin as a potential ].<ref>{{cite news |last=Clinch |first=Matt |date=10 March 2014 |title=Roubini launches stinging attack on bitcoin |url=https://www.cnbc.com/2014/03/10/nches-stinging-attack-on-bitcoin.html |publisher=] |access-date=22 November 2023 |archive-date=9 July 2022 |archive-url=https://web.archive.org/web/20220709232801/https://www.cnbc.com/2014/03/10/nches-stinging-attack-on-bitcoin.html |url-status=live }}</ref><ref>{{cite news |title=This Billionaire Just Called Bitcoin a 'Pyramid Scheme' |work=]|url=https://fortune.com/2017/07/27/howard-marks-bitcoin-pyramid-scheme |url-status=live |archive-url=https://web.archive.org/web/20170924045918/http://fortune.com/2017/07/27/howard-marks-bitcoin-pyramid-scheme/ |archive-date=24 September 2017 |access-date=23 September 2017}}</ref><ref>{{cite news |last1=Ott Ummelas |last2=Milda Seputyte |date=31 January 2014 |title=Bitcoin 'Ponzi' Concern Sparks Warning From Estonia Bank |work=Bloomberg News |url=https://www.bloomberg.com/news/2014-01-30/bitcoin-ponzi-scheme-worry-sparks-estonia-central-bank-caution.html |url-status=live |access-date=1 April 2014 |archive-url=https://web.archive.org/web/20140329214501/http://www.bloomberg.com/news/2014-01-30/bitcoin-ponzi-scheme-worry-sparks-estonia-central-bank-caution.html |archive-date=29 March 2014 |url-access=subscription}}</ref> Legal scholar ] disagrees, however, as "a real Ponzi scheme takes fraud; bitcoin, by contrast, seems more like a collective ]".<ref>{{Cite news |last=Posner |first=Eric |author-link=Eric Posner |date=11 April 2013 |title=Fool's Gold |language=en-US |work=Slate |url=https://slate.com/news-and-politics/2013/04/bitcoin-is-a-ponzi-scheme-the-internet-currency-will-collapse.html |access-date=22 November 2023 |issn=1091-2339 |archive-date=8 July 2022 |archive-url=https://web.archive.org/web/20220708202651/https://slate.com/news-and-politics/2013/04/bitcoin-is-a-ponzi-scheme-the-internet-currency-will-collapse.html |url-status=live }}</ref> A 2014 ] report also concluded that bitcoin was not a deliberate Ponzi scheme.<ref>{{Cite book |last1=Davradakis |first1=Emmanouil |last2=Santos |first2=Ricardo |url=https://data.europa.eu/doi/10.2867/11329 |title=Blockchain, FinTechs and their relevance for international financial institutions |date=2019 |publisher=] |doi=10.2867/11329 |isbn=978-92-861-4184-3 |access-date=24 November 2023 |archive-date=21 April 2024 |archive-url=https://web.archive.org/web/20240421113801/https://op.europa.eu/en/publication-detail/-/publication/ae472145-237a-11e9-8d04-01aa75ed71a1/language-en |url-status=live }}</ref> | |||
The bitcoin exchange service ] launched the first regulated bitcoin exchange in 25 US states on 26 January 2015. At the time of the announcement, CEO Brian Armstrong stated that Coinbase intends to expand to thirty countries by the end of 2015.<ref>{{cite web |url=http://techcrunch.com/2015/01/25/coinbase-us-bitcoin-exchange/ |title=Coinbase Is Opening The First Regulated Bitcoin Exchange In The U.S. |date=25 January 2015 |accessdate=21 February 2015 |website=TechCrunch |publisher=TechCrunch |last=Russel |first=Jon}}</ref> A spokesperson for ], the superintendent of New York state's Department of Financial Services, stated that Coinbase is operating without a license in the state of New York. Lawsky is responsible for the development of the so-called ']', which companies need to acquire in order to legally operate in New York.<ref>{{Cite news |url=http://dealbook.nytimes.com/2015/01/28/coinbase-a-bitcoin-exchange-is-operating-without-licenses-so-far/ |title=Coinbase, a Bitcoin Exchange, Is Operating Without Licenses So Far |date=28 January 2015 |accessdate=21 February 2015 |website=New York Times |publisher=New York Times |last=Popper |first=Nathaniel}}</ref> | |||
==See also== | |||
In August 2015 it was announced that ] would become the first UK high street bank to start accepting bitcoin, with the bank revealing that it plans to allow users to make charitable donations using the currency.<ref>{{cite web |url=http://www.dailymail.co.uk/news/article-3216246/Barclays-UK-high-street-bank-accept-bitcoin.html |title=Barclays set to become first UK high street bank to accept bitcoin as it starts taking charity donations in the virtual currency |first=Tim |last=Macfarlan |publisher=Daily Mail |date=30 August 2015 |accessdate=1 September 2015}}</ref> | |||
A major bitcoin exchange, ], was hacked and nearly 120,000 BTC (around $60m) was stolen in 2016.<ref name="bitfinexheist">{{cite news |last1=Coppola |first1=Frances |title=Theft And Mayhem In The Bitcoin World |url=http://www.forbes.com/sites/francescoppola/2016/08/06/theft-and-mayhem-in-the-bitcoin-world/#3adc93c251ae |accessdate=15 August 2016 |work=Forbes |date=6 August 2016}}</ref> | |||
== Economics == | |||
=== Classification === | |||
According to the director of the Institute for Money, Technology and Financial Inclusion at the ] there is "an unsettled debate about whether bitcoin is a currency".<ref name="currencydispute">{{cite news |url=http://www.usatoday.com/story/money/business/2014/04/25/ozy-bitcoin-africa-currency/8148853/ |title=How bitcoin is moving money in Africa |publisher=USA Today |work=usatoday.com |date=25 April 2014 |accessdate=25 May 2014 |author=Joyner, April}}</ref> Bitcoin is commonly referred to with terms like: digital currency,<ref name="primer" />{{rp|1}} ],<ref>{{cite news |url=http://www.nytimes.com/2013/08/01/technology/personaltech/virtual-currency-gains-ground-in-actual-world.html |title=Virtual Currency Gains Ground in Actual World |publisher=The New York Times |date=31 July 2013 |accessdate=6 May 2014 |author=Murphy, Kate |quote="A type of digital cash, bitcoins were invented in 2009 and can be sent directly to anyone, anywhere in the world."}}</ref> ],<ref name="satoshi unit" /> ],<ref name="capitalization" /> or ].<ref name="currencydispute" /> Its inventor,<ref name="NY2011" /> Satoshi Nakamoto, used the term electronic cash.<ref name="paper" /> Bitcoins have three useful qualities in a currency, according to ''The Economist'' in January 2015: they are "hard to earn, limited in supply and easy to verify".<ref name=ec1305 /> Economists define money as a ], a ], and a ] and agree that bitcoin has some way to go to meet all these criteria.<ref name=econ315 /> It does best as a medium of exchange, {{as of|2015|2|lc=y}} the number of merchants accepting bitcoin has passed 100,000.<ref name=100tmerchants /> {{As of|2014|3}}, the bitcoin market suffered from ], limiting the ability of bitcoin to act as a stable store of value, and retailers accepting bitcoin use other currencies as their principal unit of account.<ref name=econ315>{{cite news |title=Free Exchange. Money from nothing. Chronic deflation may keep Bitcoin from displacing its rivals. |url=http://www.economist.com/news/finance-and-economics/21599053-chronic-deflation-may-keep-bitcoin-displacing-its-fiat-rivals-money |accessdate=25 March 2014 |newspaper=The Economist |date=15 March 2014}}</ref> | |||
Journalists and academics also debate what to call bitcoin. Some media outlets do make a distinction between "real" money and bitcoins,<ref>{{cite web |url=http://www.bloombergview.com/articles/2013-11-29/building-better-bitcoins |title=Building Better Bitcoins |publisher=Bloomberg LP |work=Bloomberg View |date=29 November 2013 |accessdate=25 May 2014 |author=Carter, Stephen L. |quote=A principal knock on bitcoins has been the claim that they are inherently insecure. The principal defense has been that they are as secure as "real" currency.}}</ref> while others call bitcoin real money.<ref>{{cite news |last1=Satran |first1=Richard |title=How Did Bitcoin Become a Real Currency? |url=http://money.usnews.com/money/personal-finance/articles/2013/05/15/how-did-bitcoin-become-a-real-currency |accessdate=22 December 2014 |work=Forbes |date=15 May 2013}}</ref> '']'' declared it a commodity in December 2013.<ref>{{cite news |url=http://blogs.wsj.com/venturecapital/2013/12/12/with-25m-coinbase-to-push-bitcoin-from-commodity-to-currency/ |title=Coinbase to Push Bitcoin From Commodity to Currency, With $25M From Investors |publisher=The Wall Street Journal |date=12 December 2013 |accessdate=27 January 2014 |author=Chapman, Lizette}}</ref> A '']'' journalist referred to it as digital collectible.<ref>{{cite news |url=http://www.forbes.com/sites/louiswoodhill/2013/04/11/bitcoins-are-digital-collectibles-not-real-money/ |title=Bitcoins Are Digital Collectibles, Not Real Money |publisher=Forbes |date=4 November 2013 |accessdate=27 January 2014 |author=Woodhill, Louis}}</ref> Two ] computer scientists proposed the term "money-like informational commodity".<ref name="mlic">{{cite arXiv |author1=Bergstra, J. A. |author2=Weijland, P. |date=February 2014 |title=Bitcoin: a money-like informational commodity |arxiv=1402.4778}}</ref> ''The Wall Street Journal'',<ref name="WSJ2015-11">{{cite news |last1=Casey |first1=Michael J. |title=Ex-J.P. Morgan CDS Pioneer Blythe Masters To Head Bitcoin-Related Startup |url=http://www.wsj.com/articles/ex-j-p-morgan-cds-pioneer-blythe-masters-to-head-bitcoin-trading-platform-1426048878 |accessdate=19 November 2015 |work=Markets |publisher=] |date=11 March 2015}}</ref> '']'',<ref>{{cite news |title=Block Chain 2.0: The Renaissance of Money |url=http://www.wired.com/insights/2015/01/block-chain-2-0/ |accessdate=4 January 2016 |publisher=Wired |first=Kariappa |last=Bheemaiah}}</ref> '']'',<ref>{{cite news |last1=Groom |first1=Nelson |title=Revealed, the elusive creator of Bitcoin: Founder of digital currency is named as an Australian academic after police raid his Sydney home |url=http://www.dailymail.co.uk/news/article-3352117/Man-controversial-currency-Bitcoin-Australian-academic.html |accessdate=4 January 2016 |publisher=Daily Mail Australia |date=9 December 2015}}</ref> ''Forbes'',<ref name="forbes151021">{{cite news |last1=Shin |first1=Laura |title=Q&A: Chain.com CEO Adam Ludwin On How Money Will Become Digital |url=http://www.forbes.com/sites/laurashin/2015/10/21/qa-chain-com-ceo-adam-ludwin-on-how-money-will-become-digital/ |accessdate=4 January 2016 |publisher=Forbes |date=21 October 2015}}</ref> '']''<ref>{{cite news |title=BitGo Partners With Powerhouse Kraken Bitcoin Exchange |url=http://www.businesswire.com/news/home/20151110006264/en/BitGo-Partners-Powerhouse-Kraken-Bitcoin-Exchange |accessdate=4 January 2016 |publisher=Business Wire |date=10 November 2015}}</ref> and '']''<ref name="reuterspricing">{{cite news |last1=Polansek |first1=Tom |title=CME, ICE prepare pricing data that could boost bitcoin |url=http://www.reuters.com/article/us-cme-group-bitcoin-idUSKCN0XT1G1 |accessdate=3 May 2016 |publisher=] |date=2 May 2016}}</ref> used the ] classification for bitcoin. In a 2016 ''Forbes'' article, bitcoin was characterized as a member of a new asset class.<ref>{{cite news |last1=Shin |first1=Laura |title=4 Reasons Why Bitcoin Represents A New Asset Class |url=http://www.forbes.com/sites/laurashin/2016/06/02/4-reasons-why-bitcoin-represents-a-new-asset-class/#152663b35ce5 |accessdate=3 June 2016 |publisher=Forbes |date=2 June 2016}}</ref> | |||
The ] has stated that bitcoin "is fundamentally not a currency but an investment target".<ref name="bloomberg.com">{{cite news |url=http://www.bloomberg.com/news/2014-04-10/china-s-bitcoin-exchanges-say-banks-will-close-their-accounts.html |title=China's Bitcoin Exchanges Say Banks Will Close Their Accounts |quote=The central bank will keep watching risks from Bitcoin, which is fundamentally not a currency but an investment target, Sheng Songcheng, head of the monetary authority's statistics department, told reporters in Beijing on Jan. 15 2014. |newspaper=Bloomberg |date=10 April 2014 |accessdate=11 April 2014}}</ref> | |||
In addition to the above, bitcoin is also characterized as a payment system.{{r|primer|p=1}}<ref name="Reutersmerchants" /> | |||
===Decentralization=== | |||
{{POV section|talk=POV in the "Decentralized currency?" section|date=October 2016}} | |||
Per sources such as the academic ''Mercatus Center'',{{r|primer}} U.S. Treasury,{{r|JSC}} ''Reuters'',{{r|Reuters101}} ''The Washington Post'',{{r|USoff}} ''The Daily Herald'',{{r|dh150613}} ''The New Yorker'',{{r|kopstein}} and others, bitcoin is decentralized. | |||
There is, however, also an article that appeared in IEEE Security & Privacy magazine, in which it is stated that "contrary to widespread belief, it isn’t truly decentralized as it's deployed and implemented today."<ref>{{cite news|last1=Gervais|first1=Arthur|last2=Karame|first2=Ghassan O.|last3=Capkun|first3=Vedran|last4=Capkun|first4=Srdjan|title=Is Bitcoin a Decentralized Currency?|url=https://www.infoq.com/articles/is-bitcoin-a-decentralized-currency/|accessdate=11 October 2016|work=InfoQ|publisher=InfoQ & IEEE computer society}}</ref> | |||
According to a self-published article by Dean Walsh, "Crucially, it is important to recognize that bitcoin is not entirely decentralized, and that the degree to which it is can vary over time and be influenced by a wide range of different factors."<ref>http://cryptorials.io/centralization-problem-bitcoin-time-stopped-ignoring/ Retrieved October-9-2016</ref> | |||
=== Buying and selling === | |||
] | |||
Bitcoins can be bought and sold both on- and offline. Participants in online ] offer bitcoin ]. Using an online exchange to obtain bitcoins entails some risk, and, according to a study published in April 2013, 45% of exchanges fail and take client bitcoins with them.<ref name="wired45">{{cite web |url=http://www.wired.co.uk/news/archive/2013-04/26/large-bitcoin-exchanges-attacks |title=Study: 45 percent of Bitcoin exchanges end up closing |date=26 April 2013 |work=Wired |accessdate=28 April 2013 |author=Steadman, Ian |deadurl=no}}</ref> Exchanges have since implemented measures to provide proof of reserves in an effort to convey transparency to users.<ref name="proofofreserves">{{cite web |url=http://www.coindesk.com/krakens-audit-proves-holds-100-bitcoins-reserve/ |title=Kraken Bitcoin Exchange Passes 'Proof of Reserves' Cryptographic Audit |author=Nermin Hajdarbegovic |date=24 March 2014 |accessdate=13 January 2015 |publisher=CoinDesk |deadurl=no}}</ref><ref>{{cite news |last1=Volat |first1=Joe |title=Bitfinex and BitGo Partner to Create World's First Real-Time Proof of Reserve Bitcoin Exchange |url=http://www.businesswire.com/news/home/20150603005462/en/Bitfinex-BitGo-Partner-Create-World%E2%80%99s-Real-Time-Proof |accessdate=5 November 2015 |publisher=Business Wire |date=3 June 2015}}</ref> Offline, bitcoins may be purchased directly from an individual<ref>{{cite web |author=Lauren Orsini |url=http://www.businessinsider.com/heres-what-happened-when-i-bought-bitcoin-in-person-2013-10 |title=Here's What Happened When I Bought Bitcoin In Person |publisher=Business Insider |date=23 October 2013 |accessdate=4 February 2014}}</ref> or at a ].<ref>{{cite news |url=http://www.usatoday.com/story/money/business/2014/02/19/bitcoin-atm-austin/5623387/ |work=USA Today |date=20 February 2014 |first=Rick |last=Jervis |title=Bitcoin ATMs come to USA |accessdate=31 October 2014}}</ref> Bitcoin machines are not however traditional ATMs. Bitcoin kiosks are machines connected to the Internet, allowing the insertion of cash in exchange for bitcoins. Bitcoin kiosks do not connect to a bank and may also charge transaction fees as high as 7% and exchange rates $50 over rates from elsewhere.<ref name="files.consumerfinance.gov">{{cite web |title=Risks to consumers posed by virtual currencies |url=http://files.consumerfinance.gov/f/201408_cfpb_consumer-advisory_virtual-currencies.pdf |publisher=] |accessdate=10 July 2016 |date=August 2014}}</ref> | |||
=== Price and volatility === | |||
] | |||
According to ], {{as of | 2014 | lc = y}}, bitcoin has ] seven times greater than gold, eight times greater than the ], and eighteen times greater than the U.S. dollar.<ref>{{cite web |url=http://management.bu.edu/files/2014/10/Wlliams-World-Bank-10-21-2014.pdf |title=Virtual Currencies – Bitcoin Risk |publisher=Boston University |work=World Bank Conference Washington DC |date=21 October 2014 |accessdate=11 November 2014 |author=Williams, Mark T.}}</ref> | |||
Attempting to explain the high volatility, a group of Japanese scholars stated that there is no stabilization mechanism.<ref>{{cite web |author1=Mitsuru Iwamura |author2=Tsutomu Matsumoto |author3=Kenji Saito |author4=Yukinobu Kitamura |title=Can We Stabilize the Price of Cryptocurrency?: Understanding the Design of Bitcoin and its Potential Competitiveness with the Central Bank Money |url=http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2519367 |website=Social Science Research Network |accessdate=8 January 2015 |date=24 July 2014 |quote="The first instability stems from an inflexible supply curve of Bitcoin, which amplifies Bitcoin price volatility; the miners’ revenue/reward fully absorbs any price changes. There is no price stabilization mechanism."}}</ref> The Bitcoin Foundation contends that high volatility is due to insufficient ],<ref>{{cite news |last=Wilkes |first=Tommy |url=http://www.reuters.com/article/2013/04/11/us-bitcoin-currency-idUSBRE93A0P020130411 |title=Backer defends virtual currency Bitcoin after big fall |publisher=Reuters |date=11 April 2013 |accessdate=7 January 2014}}</ref> while a ''Forbes'' journalist claims that it is related to the uncertainty of its long-term ],<ref>{{cite news |last=Lee |first=Timothy B. |title=Bitcoin Doesn't Have a Deflation Problem |url=http://www.forbes.com/sites/timothylee/2013/04/11/bitcoin-doesnt-have-a-deflation-problem/ |work=Forbes |location= |date=4 November 2013 |accessdate=27 January 2014}}</ref> and the high volatility of a startup currency makes sense, "because people are still experimenting with the currency to figure out how useful it is."<ref name="VolatilityFatal" /> | |||
There are uses where volatility does not matter, such as online gambling, tipping, and international remittances.<ref name="VolatilityFatal">{{cite news |last=Lee |first=Timothy B. |url=http://www.forbes.com/sites/timothylee/2013/04/12/bitcoins-volatility-is-a-disadvantage-but-not-a-fatal-one/ |title=Bitcoin's Volatility Is A Disadvantage, But Not A Fatal One |publisher=Forbes |date=12 April 2013 |accessdate=15 November 2014}}</ref> As of 2014, pro-bitcoin venture capitalists argued that the greatly increased trading volume that planned ] exchanges would generate is needed to decrease price volatility.<ref name=wsjprice /> | |||
The price of bitcoins has gone through various cycles of appreciation and depreciation referred to by some as ] and busts.<ref>{{cite news |url=http://www.forbes.com/sites/jessecolombo/2013/12/19/bitcoin-may-be-following-this-classic-bubble-stages-chart/ |title=Bitcoin May Be Following This Classic Bubble Stages Chart |publisher=Forbes |date=19 December 2013 |accessdate=7 January 2014 |first=Jesse |last=Colombo}}</ref><ref>{{cite web |url=http://www.theguardian.com/commentisfree/2013/apr/03/bitcoin-currency-bubble-crash-not-rocking-financial-markets |title=Confused about Bitcoin? It's 'the Harlem Shake of currency' |publisher=The Guardian |work=theguardian.com |date=3 April 2013 |accessdate=2 May 2014 |author=Moore, Heidi}}</ref> In 2011, the value of one bitcoin rapidly rose from about US$0.30 to US$32 before returning to US$2.<ref name="Leebubble">{{cite news |url=http://www.washingtonpost.com/blogs/the-switch/wp/2013/11/05/when-will-the-people-who-called-bitcoin-a-bubble-admit-they-were-wrong |title=When will the people who called Bitcoin a bubble admit they were wrong |publisher=The Washington Post |date=5 November 2013 |accessdate=10 January 2014 |author=Lee, Timothy}}</ref> In the latter half of 2012 and during the ], the bitcoin price began to rise,<ref>{{cite web |last=Liu |first=Alec |url=http://motherboard.vice.com/blog/cyprus-spain-when-governments-take-your-money-bitcoin-looks-really-good |title=When Governments Take Your Money, Bitcoin Looks Really Good |publisher=Motherboard |date=19 March 2013 |accessdate=7 January 2014}}</ref> reaching a high of US$266 on 10 April 2013, before crashing to around US$50.<ref>{{cite news |url=http://www.forbes.com/sites/timothylee/2013/04/11/an-illustrated-history-of-bitcoin-crashes/ |title=An Illustrated History Of Bitcoin Crashes |publisher=Forbes |date=11 April 2013 |accessdate=7 January 2014 |first=Timothy B. |last=Lee}}</ref> On 29 November 2013, the cost of one bitcoin rose to the all-time peak of US$1,242.<ref>{{cite news |url=http://money.cnn.com/2013/11/29/investing/bitcoin-gold/index.html |title=Bitcoin worth almost as much as gold |author=Ben Rooney |date=29 November 2013 |publisher=CNN |accessdate=31 October 2014}}</ref> In 2014, the price fell sharply, and as of April remained depressed at little more than half 2013 prices. {{As of|2014|August}} it was under US$600.<ref>{{cite web |url=http://www.nasdaq.com/article/bitcoin-prices-remain-below-600-amid-bearish-chart-signals-cm376685 |title=Bitcoin prices remain below $600 amid bearish chart signals |publisher=nasdaq.com |date=August 2014 |accessdate=31 October 2014}}</ref> In January 2015, noting that the bitcoin price had dropped to its lowest level since spring 2013 – around US$224 – '']'' suggested that "ith no signs of a rally in the offing, the industry is bracing for the effects of a prolonged decline in prices. In particular, bitcoin mining companies, which are essential to the currency's underlying technology, are flashing warning signs."<ref>{{cite news |last1=Ember |first1=Sydney |title=As Bitcoin's Price Slides, Signs of a Squeeze |url=http://dealbook.nytimes.com/2015/01/13/as-bitcoins-price-slides-signs-of-a-squeeze/?_r=0 |accessdate=16 January 2015 |publisher=New York Times |date=13 January 2015}}</ref> Also in January 2015, '']'' reported that ] drug dealers were "freaking out" as they lost profits through being unable to convert bitcoin revenue to cash quickly enough as the price declined – and that there was a danger that dealers selling reserves to stay in business might force the bitcoin price down further.<ref>{{cite news |last1=Price |first1=Rob |title=Deep Web Drug Dealers Are Freaking Out About The Bitcoin Crash |url=http://uk.businessinsider.com/bitcoin-crash-drug-dealers-2015-1?r=US |accessdate=18 January 2015 |publisher=Business Insider |date=16 January 2015}}</ref> | |||
On 4 November 2015, bitcoin had risen by more than 20%, exceeding $490. The '']'' associated the rapid growth with the popularity of "socio-financial networks" MMM operated by Russian businessman Sergei Mavrodi.<ref>{{Cite news |title=Bitcoin surges as Chinese flock to Russian fraudster's site |url=http://www.ft.com/cms/s/2/ee93bc2e-82f6-11e5-8095-ed1a37d1e096.html#axzz3wkFu89oV |newspaper=Financial Times |date=4 November 2015|access-date = 23 January 2016 |issn=0307-1766 |first=Izabella |last=Kaminska |first2=Dan |last2=McCrum |first3=Robin |last3=Kwong}}</ref> | |||
=== Speculative bubble dispute === | |||
Bitcoin has been labelled a '']'' by many including former ] ]<ref name=Kearns>{{cite news |url=http://www.bloomberg.com/news/2013-12-04/greenspan-says-bitcoin-a-bubble-without-intrinsic-currency-value.html |title=Greenspan Says Bitcoin a Bubble Without Intrinsic Currency Value |publisher=Bloomberg LP |work=bloomberg.com |date=4 December 2013 |accessdate=23 December 2013 |author=Kearns, Jeff}}</ref> and economist ].<ref name="BMH">{{cite news |url=http://nationalinterest.org/commentary/the-bitcoin-bubble-bad-hypothesis-8353 |title=The Bitcoin Bubble and a Bad Hypothesis |last=Quiggin |first=John |work=The National Interest |date=16 April 2013 |deadurl=no |accessdate=31 October 2014}}</ref> ] laureate ] said that bitcoin "exhibited many of the characteristics of a speculative bubble".<ref>{{cite news |last=Shiller |first=Robert |title=In Search of a Stable Electronic Currency |url=http://www.nytimes.com/2014/03/02/business/in-search-of-a-stable-electronic-currency.html?_r=0 |publisher=New York Times |date=1 March 2014 |accessdate=31 October 2014 |deadurl=no}}</ref> Two lead software developers of bitcoin, ]<ref>{{cite web |title=Bitcoin's History of Crushing Speculators |author=Dan Caplinger |publisher=] |date=4 April 2013 |accessdate=7 January 2014 |url=http://www.fool.com/retirement/general/2013/04/04/bitcoins-history-of-crushing-speculators.aspx}}</ref> and Mike Hearn,<ref>{{cite news |url=http://www.bbc.co.uk/news/magazine-25332746 |title=Bitcoin: Price v hype |publisher=BBC |work=bbc.com |date=13 December 2013 |accessdate=23 December 2013 |author=Barford, Vanessa}}</ref> have warned that bubbles may occur. David Andolfatto, a vice president at the ], stated, "Is bitcoin a bubble? Yes, if bubble is defined as a liquidity premium." According to Andolfatto, the price of bitcoin "consists purely of a bubble," but he concedes that many assets have prices that are greater than their intrinsic value.<ref name="Andolfatto2014-03" />{{rp|21}} Journalist Matthew Boesler rejects the speculative bubble label and sees bitcoin's quick rise in price as nothing more than normal economic forces at work.<ref>{{cite web |last=Boesler |first=Matthew |title=ANALYST: The Rise Of Bitcoin Teaches A Tremendous Lesson About Global Economics |url=http://www.businessinsider.com/global-economics-lesson-from-bitcoin-2013-3 |publisher=Business Insider |date=7 March 2013 |accessdate=31 October 2014 |deadurl=no}}</ref> The ''Washington Post'' pointed out that the observed cycles of appreciation and depreciation don't correspond to the definition of speculative bubble.<ref name="Leebubble" /> | |||
=== Ponzi scheme concerns === | |||
Various journalists,<ref name="dh150613" /><ref>{{cite news|last1=Braue|first1=David|title=Bitcoin confidence game is a Ponzi scheme for the 21st century|url=http://www.zdnet.com/article/bitcoin-confidence-game-is-a-ponzi-scheme-for-the-21st-century/|accessdate=5 October 2016|publisher=ZDNet|date=11 March 2014}}</ref> economists,<ref>{{cite web |url=http://www.cnbc.com/id/101479123 |title=Roubini launches stinging attack on bitcoin |publisher=] |date=10 March 2014 |accessdate=2 July 2014 |author=Clinch, Matt}}</ref><ref name="dd">{{cite web |url=http://www.dailydot.com/opinion/why-bitcoin-ponzi-scheme/ |title=Bitcoins: The second biggest Ponzi scheme in history |publisher=The Daily Dot |date=3 December 2013 |accessdate=23 May 2016 |author=North, Gary | author-link=Gary North (economist)}}</ref> and the central bank of Estonia<ref name="Ott Ummelas and Milda Seputyte">{{cite news |url=http://www.bloomberg.com/news/2014-01-30/bitcoin-ponzi-scheme-worry-sparks-estonia-central-bank-caution.html |title=Bitcoin ‘Ponzi’ Concern Sparks Warning From Estonia Bank |publisher=Bloomberg |work=bloomberg.com |date=31 January 2014 |accessdate=1 April 2014 |author1=Ott Ummelas |author2=Milda Seputyte |lastauthoramp=yes}}</ref> have voiced concerns that bitcoin is a ].<ref name="nytimes_ponzi">{{cite web |url=http://www.nytimes.com/2014/02/25/business/apparent-theft-at-mt-gox-shakes-bitcoin-world.html?_r=2 |title=Apparent Theft at Mt. Gox Shakes Bitcoin World |publisher=] |date=25 February 2014 |accessdate=22 May 2016 |author1=Popper, Nathaniel |author2=Abrams, Rachel}}</ref> ], a law professor at the University of Chicago, stated in 2013 that "a real Ponzi scheme takes fraud; bitcoin, by contrast, seems more like a collective delusion."<ref name="Posner, Eric">{{cite web |url=http://www.slate.com/articles/news_and_politics/view_from_chicago/2013/04/bitcoin_is_a_ponzi_scheme_the_internet_currency_will_collapse.html |title=Bitcoin is a Ponzi scheme—the Internet's favorite currency will collapse. |work=Slate |date=11 April 2013 |accessdate=1 April 2014 |author=Posner, Eric |authorlink=Eric Posner}}</ref> In 2014 reports by both the ] and the Swiss ] examined the concerns and came to the conclusion that bitcoin is not a Ponzi scheme.<ref>{{cite web |title=Ponzis: The Science and Mystique of a Class of Financial Frauds |url=http://www-wds.worldbank.org/external/default/WDSContentServer/WDSP/IB/2014/07/16/000112742_20140716115536/Rendered/PDF/WPS6967.pdf |author=Kaushik Basu |publisher=] |date=July 2014 |accessdate=30 October 2014}}</ref>{{rp|7}}<ref name="FC20140625">{{cite web |publisher=] |title=Federal Council report on virtual currencies in response to the Schwaab (13.3687) and Weibel (13.4070) postulates |work=] |date=25 June 2014 |accessdate=28 November 2014 |url=http://www.news.admin.ch/NSBSubscriber/message/attachments/35355.pdf}}</ref>{{rp|21}} However, bitcoin is still 'a little bit' of a Ponzi sceme or pyramid scheme according to some mainstream writers such as Matt O Brien of the ] who said its early adopters are trying to cash in on the idea of getting more people involved, driving the bitcoin price up and increasing their funds.<ref>Retrieved October-1-2016 http://www.dailyherald.com/article/20150613/business/150619551/</ref><ref>http://www.ft.com/cms/s/0/1877c388-8797-11e5-90de-f44762bf9896.html#axzz4LoGkuNVl Retrieved October-1-2016</ref><ref>http://www.bloomberg.com/news/videos/b/c6454137-4042-4d83-a1e4-ed77253b7652 Retrieved October-1-2016</ref> | |||
=== Value forecasts === | |||
Financial journalists and analysts, economists, and investors have attempted to predict the possible future value of bitcoin. In April 2013, economist ] stated, "bitcoins will attain their true value of zero sooner or later, but it is impossible to say when".<ref name="BMH" /> A similar forecast was made in November 2014 by economist ].<ref>{{cite news |author=Kevin Dowd |title=Bitcoin is bust: Why investors should abandon the doomed cryptocurrency |url=http://www.cityam.com/1415215686/bitcoin-bust-why-investors-should-abandon-doomed-cryptocurrency |date=5 November 2014 |accessdate=6 November 2014 |work=Opinion |publisher=]}}</ref> | |||
In December 2013, finance professor ] forecast a bitcoin would be worth less than $10 by July 2014.<ref>{{cite web |url=http://www.businessinsider.com/williams-bitcoin-meltdown-10-2013-12 |title=FINANCE PROFESSOR: Bitcoin Will Crash To $10 By Mid-2014 |publisher=Business Insider |work=businessinsider.com |date=17 December 2013 |accessdate=26 February 2014 |author=Williams, Mark T.}}</ref> In the indicated period bitcoin has exchanged as low as $344 (April 2014) and during July 2014 the bitcoin low was $609.<ref name="Blockchain.info" /><ref>{{cite news |work=Huffington Post |publisher=TheHuffingtonPost.com, Inc. |author=Steve H. Hanke |title=Bitcoin Charts, Finally |date=18 September 2014 |accessdate=21 November 2014 |url=http://www.huffingtonpost.com/steve-h-hanke/bitcoin-charts_b_5838132.html}}</ref> In December 2014, Williams said, "The probability of success is low, but if it does hit, the reward will be very large."<ref>{{cite news |title=How Mt. Gox Debacle Won Over a Bitcoin Convert |url=http://online.wsj.com/articles/how-mt-gox-debacle-won-over-a-bitcoin-convert-1417471759 |author=Robin Sidel |date=1 December 2014 |accessdate=4 December 2014 |publisher=The Wall Street Journal |work=Markets}}</ref> | |||
In November 2014, David Yermack, Professor of Finance at New York University Stern School of Business, forecast that in November 2015 bitcoin may be all but worthless.<ref>{{cite news |url=http://www.cnn.com/2014/11/13/tech/bitcoin-peak-price-future |title=Bitcoin: One year on from peak price, what does the future hold? |accessdate=15 November 2014 |publisher=CNN |work=Future Finance |date=14 November 2014 |author=Eoghan Macguire}}</ref> In the indicated period bitcoin has exchanged as low as $176.50 (January 2015) and during November 2015 the bitcoin low was $309.90.<ref name="Blockchain.info" /> | |||
In May 2013, ] FX and Rate Strategist David Woo forecast a maximum fair value per bitcoin of $1,300.<ref name="BoAFA">{{cite news |last=Sharf |first=Samantha |title=Bitcoin Gets Valued: Bank Of America Puts A Price Target On The Virtual Tender |url=http://www.forbes.com/sites/samanthasharf/2013/12/05/bitcoin-gets-valued-bank-of-america-puts-a-price-on-the-virtual-tender/ |work=Forbes |location=New York |date=12 May 2013 |accessdate=31 October 2014}}</ref> | |||
=== Obituaries === | |||
The "death" of bitcoin has been proclaimed numerous times.<ref name="cnbcworries" /> One journalist has recorded 29 such "obituaries" as of early 2015.<ref name="cnbcworries">{{cite news |author1=Everett Rosenfeld |title=Bitcoin keeps falling, and worries keep rising |url=http://www.cnbc.com/id/102337172#. |accessdate=24 January 2015 |publisher=CNBC |date=14 January 2015}}</ref> | |||
'']'' magazine declared bitcoin "dead" in June 2011,<ref>{{cite news |last1=Worstall |first1=Tim |title=So, That's the End of Bitcoin Then |url=http://www.forbes.com/sites/timworstall/2011/06/20/so-thats-the-end-of-bitcoin-then/ |accessdate=18 January 2015 |work=Forbes |date=20 June 2011}}</ref> followed by ''Gizmodo Australia'' in August 2011.<ref>{{cite news |last1=Covert |first1=Adrian |title=The Bitcoin Is Dying. Whatever. |url=http://www.gizmodo.com.au/2011/08/the-bitcoin-is-dying-whatever/ |accessdate=18 January 2015 |work=Gizmodo Australia |publisher=Allure Media |date=9 August 2011}}</ref> ] magazine wrote it had "expired" in December 2012.<ref>{{cite news |last1=Calore |first1=Michael |title=Wired, Tired, Expired for 2012: From Stellar to Suck |url=http://www.wired.com/2012/12/wired-tired-expired/#slideid-331231 |accessdate=18 January 2015 |work=Wired |publisher=Condé Nast |date=24 December 2012}}</ref> ''Ouishare Magazine'' declared, "game over, bitcoin" in May 2013,<ref>{{cite news |last1=Jourdan |first1=Stanislas |title=Game over, bitcoin. Where is the next human-based digital currency? |url=http://magazine.ouishare.net/2013/05/bitcoin-human-based-digital-currency/ |accessdate=18 January 2015 |work=Ouishare Magazine |date=21 May 2013}}</ref> and ''New York Magazine'' stated bitcoin was "on its path to grave" in June 2013.<ref>{{cite news |last1=Roose |first1=Kevin |title=Bitcoin Sees the Grim Reaper |url=http://nymag.com/daily/intelligencer/2013/06/bitcoin-sees-the-grim-reaper.html |accessdate=18 January 2015 |work=New York Magazine |publisher=New York Media LLC |date=20 June 2013}}</ref> ''Reuters'' published an "obituary" for bitcoin in January 2014.<ref>{{cite news |last1=Hadas |first1=Edward |title=An early obituary for bitcoin |url=http://blogs.reuters.com/edward-hadas/2014/01/08/an-early-obituary-for-bitcoin/ |accessdate=18 January 2015 |publisher=Reuters |date=8 January 2014}}</ref> ''Street Insider'' declared bitcoin "dead" in February 2014,<ref>{{cite news |title=Bitcoin is Dead |url=http://www.streetinsider.com/Analyst+Comments/Bitcoin+is+Dead/9219338.html |accessdate=18 January 2015 |publisher=Streetinsider.com |date=26 February 2014}}</ref> followed by ''The Weekly Standard'' in March 2014,<ref>{{cite news |last1=Last |first1=Jonathan V. |title=Bitcoin Is Dead |url=http://www.weeklystandard.com/blogs/bitcoin-dead_784187.html |accessdate=18 January 2015 |work=The Weekly Standard |publisher=The Weekly Standard LLC |date=5 March 2014}}</ref> ''Salon'' in March 2014,<ref>{{cite news |last1=Leonard |first1=Andrew |title=Sorry, libertarians: Your dream of a Bitcoin paradise is officially dead and gone |url=http://www.salon.com/2014/03/07/sorry_libertarians_your_dream_of_a_bitcoin_paradise_is_officially_dead_and_gone/ |accessdate=18 January 2015 |work=Salon |publisher=Salon Media Group Inc. |date=7 March 2014}}</ref> ''Vice News'' in March 2014,<ref>{{cite news |last1=Owen |first1=Taylor |title=Bitcoin Is Dead — Long Live Bitcoin |url=https://news.vice.com/article/bitcoin-is-dead-long-live-bitcoin |accessdate=18 January 2015 |work=Vice News |date=24 March 2014}}</ref> and ''Financial Times'' in September 2014.<ref>{{cite news |last1=Kaminska |first1=Izabella |title=Cult Markets: When the bubble bursts |url=http://ftalphaville.ft.com/2014/09/19/1976132/cult-markets-when-the-bubble-bursts |work=Financial Times |date=19 September 2014}}</ref> In January 2015, ''USA Today'' states bitcoin was "headed to the ash heap",<ref>{{cite news |last1=Krantz |first1=Matt |title=Bitcoin is headed to the 'ash heap' |url=http://americasmarkets.usatoday.com/2015/01/16/bitcoin-is-headed-to-the-ash-heap/ |accessdate=18 January 2015 |work=USA Today |date=16 January 2015}}</ref> and ''The Telegraph'' declared "the end of bitcoin experiment".<ref>{{cite news |last1=Sparkes |first1=Matthew |title=Bitcoin might be dead. It doesn't matter. |url=http://www.telegraph.co.uk/technology/news/11347205/Bitcoin-might-be-dead.-It-doesnt-matter..html |accessdate=18 January 2015 |work=The Telegraph |date=15 January 2015 |location=London}}</ref> In January 2016, former bitcoin developer Mike Hearn called bitcoin a "failed project".<ref>{{cite news |last1=Baraniuk |first1=Chris |title=Bitcoin: Is the crypto-currency doomed? |url=http://www.bbc.com/news/technology-35343561 |accessdate=19 January 2016 |publisher=BBC |date=18 January 2016}}</ref> | |||
Peter Greenhill, Director of E-Business Development for the Isle of Man, commenting on the obituaries paraphrased ] saying "reports of bitcoin's death have been greatly exaggerated".<ref>{{cite web |last1=Greenhill |first1=Peter |title=Reports of Bitcoin's Death Have Been Greatly Exaggerated |url=http://www.huffingtonpost.co.uk/peter-greenhill/decline-of-bitcoin_b_6976474.html |accessdate=5 April 2015 |date=31 March 2015 |publisher=The Huffington Post}}</ref> | |||
=== Reception === | |||
Some ]s have responded positively to bitcoin while others have expressed skepticism. François R. Velde, Senior Economist at the ] described it as "an elegant solution to the problem of creating a digital currency".<ref>{{cite web |url=https://www.chicagofed.org/digital_assets/publications/chicago_fed_letter/2013/cfldecember2013_317.pdf |title=Bitcoin: A primer |date=December 2013 |accessdate=3 September 2016 |first=François |last=Velde |work=Chicago Fed letter |issue=317 |page=4 |publisher=]}}</ref> ] and ] have found fault with bitcoin questioning why it should act as a reasonably stable ] or whether there is a floor on its value.<ref>{{cite news |author=Paul Krugman |date=28 December 2013 |title=Bitcoin Is Evil |url=http://krugman.blogs.nytimes.com/2013/12/28/bitcoin-is-evil/ |publisher=] |accessdate=28 December 2013}}</ref> Economist ] has criticized bitcoin as "the final refutation of the ]".<ref name="BMH" /> | |||
David Andolfatto, Vice President at the ], stated that bitcoin is a threat to the establishment, which he argues is a good thing for the Federal Reserve System and other central banks because it prompts these institutions to operate sound policies.<ref name="Andolfatto2014-03">{{cite web |url=http://www.stlouisfed.org/dialogue-with-the-fed/assets/Bitcoin-3-31-14.pdf |title=Bitcoin and Beyond: The Possibilities and Pitfalls of Virtual Currencies |publisher=Federal Reserve Bank of St. Louis |work=Dialogue with the Fed |date=31 March 2014 |accessdate=16 April 2014 |author=Andolfatto, David}}</ref>{{rp|33}}<ref>{{cite web |url=http://www.businessinsider.com/interview-with-david-andolfatto-2014-4 |title=St. Louis Fed Economist: Bitcoin Could Be A Good Threat To Central Banks |publisher=Business Insider |work=businessinsider.com |date=6 April 2014 |accessdate=16 April 2014 |author=Wile, Rob}}</ref><ref>{{cite web |url=http://andolfatto.blogspot.com/2013/12/in-gold-we-trust.html |title=In gold we trust? |publisher=David Andolfatto |work=MacroMania |date=24 December 2013 |accessdate=17 April 2014 |quote=Also, note that I am not against gold or bitcoin (or whatever) as a currency. In fact, I think that the threat that they pose as alternate currency can serve as a useful check on a central bank. |author=Andolfatto, David}}</ref> | |||
] activist ] has criticized the lack of anonymity and called for reformed development.<ref>{{cite news |url=http://www.telegraph.co.uk/technology/news/10488201/Software-activist-calls-for-truly-anonymous-Bitcoins-to-protect-democracy.html |title=Software activist calls for 'truly anonymous' Bitcoins to 'protect democracy' |publisher=Telegraph |date=2 December 2013 |accessdate=27 December 2013 |location=London |first=Matthew |last=Sparkes}}</ref> ] President ] calls bitcoin a "great place to put assets" but claims it will not be a currency until price volatility is reduced.<ref>{{cite web |url=http://news.cnet.com/8301-1023_3-57615080-93/paypal-president-david-marcus-bitcoin-is-good-nfc-is-bad/ |title=PayPal president David Marcus: Bitcoin is good, NFC is bad |date=10 December 2013 |accessdate=10 December 2013 |first=Stephen |last=Shankland |work=CNET}}</ref> ], in relation to the cost of moving money from place to place in an interview for Bloomberg L.P. stated: "Bitcoin is exciting because it shows how cheap it can be."<ref>{{cite news |date=2 October 2014 |accessdate=12 November 2014 |title=Bill Gates: Bitcoin Is Exciting Because It's Cheap |url=http://www.bloomberg.com/video/bill-gates-bitcoin-is-exciting-because-it-s-cheap-dQ4qHV4~TLSnUIuIRfZBVA.html |publisher=Bloomberg L.P.}}</ref> | |||
Officials in countries such as ],<ref name=Braziloff>{{cite news |last1=Pomela |first1=Marina |title=Taxation on Bitcoin |url=http://thebrazilbusiness.com/article/taxation-on-bitcoin |accessdate=18 September 2015 |publisher=The Brazil Business |date=10 April 2015}}</ref> the ],<ref name="IMoff">{{cite news |first=Jeremy |last=Kahn |url=http://www.bloomberg.com/news/features/2015-09-07/isle-of-man-tax-haven-with-tailless-cats-becomes-bitcoin-hub |title=Isle of Man tax haven with tailless cats becomes bitcoin hub |date=8 September 2015 |publisher=] |accessdate=18 September 2015}}</ref> ],<ref name="Jerseyoff">{{cite news |url=http://www.bbc.co.uk/news/world-europe-jersey-28247796 |title=Jersey Approves First Regulated Bitcoin Fund |date=10 July 2014 |first=Daniel |last=Masters |publisher=BBC |work=News |accessdate=9 September 2015}}</ref> the ],<ref name="UKoff">{{cite news |last1=Hancock |first1=Edith |title=David Cameron to take UK fintech leaders on Asian tour |url=http://www.cityam.com/220980/pm-take-uk-fintech-leaders-asian-tour |accessdate=18 September 2015 |publisher=City A.M. |date=27 July 2015}}</ref> and the ]<ref name="USoff">{{cite news |url=https://www.washingtonpost.com/news/the-switch/wp/2013/11/21/heres-how-bitcoin-charmed-washington/# |title=Here's how Bitcoin charmed Washington |date=21 November 2013 |first=Timothy B. |last=Lee |work=The Washington Post |accessdate=10 October 2016}}</ref> have recognized its ability to provide legitimate financial services. Recent bitcoin developments have been drawing the interest of more financially savvy politicians and legislators as a result of bitcoin's capability to eradicate fraud, simplify transactions, and provide transparency, when bitcoins are properly utilized.<ref>{{cite news |url=http://www.ibtimes.co.uk/barclays-transfer-value-age-distributed-ledger-technology-1508849 |title=Barclays talks Blockchain, BitCoin, and Distributed Ledgers |date=1 July 2015 |first=Ian |last=Allison |publisher=International Business Times |work=Technology |accessdate=9 September 2015}}</ref><ref>{{cite news |url=http://www.forbes.com/sites/gregoryferenstein/2015/07/29/former-obama-tech-advisor-explains-how-bitcoin-could-transform-government-in-5-quotes/ |title=Former Obama Tech Advisor Explains How BitCoin Could Transform Government... |date=29 July 2015 |first=Gregory |last=Ferenstein |publisher=Forbes |work="Ferenstein Wire" |accessdate=9 September 2015}}</ref><ref>{{cite news |first=Kashmir |last=Hill |url=http://www.forbes.com/sites/kashmirhill/2014/03/05/congressman-calls-for-ban-on-u-s-dollar-in-response-to-senators-bitcoin-ban-request/ |title=Congressman calls for ban on U.S. Dollar in Response to Senator's Bitcoin ban request |date=5 March 2015 |publisher=Forbes |accessdate=9 September 2015}}</ref> | |||
=== Acceptance by merchants === | |||
] in ] in the Netherlands as of 2013]] | |||
In 2015, the number of merchants accepting bitcoin exceeded 100,000.<ref name=100tmerchants>{{cite news |last1=Cuthbertson |first1=Anthony |title=Bitcoin now accepted by 100,000 merchants worldwide |url=http://www.ibtimes.co.uk/bitcoin-now-accepted-by-100000-merchants-worldwide-1486613 |website=International Business Times |publisher=IBTimes Co., Ltd. |date=4 February 2015 |accessdate=20 November 2015}}</ref> Instead of 2{{ndash}}3% typically imposed by ] processors, merchants accepting bitcoins often pay fees in the range from 0% to less than 2%.<ref name="merchantfee" /> {{as of|2014|December}} select firms that accept payments in bitcoin include:{{refn|group=note|Retailers usually offer in-store credit, instead of a return transfer (or ]) as the only option when customers return items purchased with bitcoins.<ref>{{cite journal |url=http://www.bostonfed.org/economic/current-policy-perspectives/2014/cpp1404.pdf |title=Bitcoin as Money? |author1=Stephanie Lo |author2=J. Christina Wang |lastauthoramp=yes |journal=Current Policy Perspectives (Federal Reserve Bank of Boston) |date=September 2014 |volume=14 |issue=1 |page=6}}</ref>}} | |||
] | |||
{| class="wikitable sortable" | |||
|- | |||
! Alexa rank | |||
! Site | |||
|- | |||
| {{sort|0000033|33}}<ref> at Alexa</ref> | |||
| ]<ref>{{cite web |url=https://www.paypal-community.com/t5/PayPal-Forward/PayPal-and-Virtual-Currency/ba-p/828230 |author=Scott Ellison |title=PayPal and Virtual Currency |date=23 September 2014 |accessdate=31 October 2014 |publisher=PayPal}}</ref> | |||
|- | |||
| {{sort|0000041|41}}<ref> at Alexa</ref> | |||
| Microsoft<ref name="msftaccepts">{{cite news |author=Tom Warren |url=http://www.theverge.com/2014/12/11/7375771/microsoft-supports-bitcoin-payments |title=Microsoft now accepts Bitcoin to buy Xbox games and Windows apps |accessdate=11 December 2014 |date=11 December 2014 |publisher=Vox Media |work=The Verge}}</ref> | |||
|- | |||
| {{sort|0000328|328}}<ref> at Alexa</ref> | |||
| ]<ref name=Dell>{{cite news |url=http://dealbook.nytimes.com/2014/07/18/dell-begins-accepting-bitcoin/ |title=Dell Begins Accepting Bitcoin |author=Sydney Ember |work=New York Times |date=18 July 2014 |accessdate=18 July 2014}}</ref> | |||
|- | |||
| {{sort|0000329|329}}<ref> at Alexa</ref> | |||
| Newegg<ref>{{cite web |url=http://www.newegg.com/bitcoin |title=Newegg accepts bitcoins |work=newegg.com |date=1 July 2014 |accessdate=3 July 2014}}</ref> | |||
|- | |||
| {{sort|0000505|505}}<ref> at Alexa</ref> | |||
| Overstock.com<ref name=overstock>{{cite web |url=http://blogs.marketwatch.com/thetell/2014/01/09/bitcoin-now-accepted-on-overstock-com-through-vc-backed-coinbase/ |title=Bitcoin now accepted on Overstock.com through VC-backed Coinbase |publisher=Wall Street Journal |work=marketwatch.com |date=9 January 2014 |accessdate=10 February 2014 |author=Vaishampayan, Saumya}}</ref> | |||
|- | |||
| {{sort|0000512|512}}<ref> at Alexa</ref> | |||
| Expedia<ref>{{cite news |url=http://blogs.wsj.com/moneybeat/2014/06/11/expedia-starts-accepting-bitcoin-for-hotel-bookings/ |title=Expedia Starts Accepting Bitcoin for Hotel Bookings |author=Paul Vigna |work=Money Beat |publisher=The Wall Street Journal |date=11 June 2014 |accessdate=27 July 2014}}</ref> | |||
|- | |||
| {{sort|0001981|1,981}}<ref> at Alexa</ref> | |||
| TigerDirect<ref name=tigger>{{cite web |url=http://www.tomshardware.com/news/tigerdirect-bitcoin-bitpay-payments,25859.html |title=TigerDirect is Now Accepting Bitcoin As Payment |publisher=Tom's hardware |date=26 January 2014 |accessdate=28 August 2014 |author=Jane McEntegart}}</ref> | |||
|- | |||
| {{sort|0005674|5,674}}<ref> at Alexa</ref> | |||
| ]<ref>{{cite news |url=http://www.wsj.com/articles/dish-network-to-accept-bitcoin-payments-1401363621 |title=Dish Network to Accept Bitcoin Payments |publisher=Dow Jones & Company |work=The Wall Street Journal |date=29 May 2014 |accessdate=15 February 2015 |author=Casey, Michael}}</ref> | |||
|- | |||
| {{sort|0007038|7,038}}<ref> at Alexa</ref> | |||
| ]<ref>{{cite news |url=http://www.bloomberg.com/news/2014-01-05/bitcoin-tops-1-000-again-on-adoption-by-zynga-amid-wider-usage.html |title=Bitcoin Tops $1,000 Again as Zynga Accepts Virtual Money |publisher=Bloomberg LP |work=bloomberg.com |date=6 January 2014 |accessdate=20 January 2014 |author=Kharif, Olga}}</ref> | |||
|- | |||
| {{sort|0030565|30,565}}<ref> at Alexa</ref> | |||
| ]<ref>{{cite news |url=http://dealbook.nytimes.com/2014/12/16/time-inc-begins-accepting-bitcoin-payments/?_r=1 |title=Time Inc. begins accepting bitcoin payments |publisher=The New York Times |work=Dealbook |date=16 December 2014 |accessdate=9 January 2015 |author=Ember, Sydney}}</ref> | |||
|- | |||
| {{sort|0176903|176,903}}<ref> at Alexa</ref> | |||
| ]<ref>{{cite news |url=http://www.telegraph.co.uk/technology/news/10558191/Ten-places-where-you-can-spend-your-bitcoins-in-the-UK.html |title=Ten places where you can spend your bitcoins in the UK |date=10 January 2014 |accessdate=10 September 2013 |first=Matthew |last=Sparkes |work=The Telegraph |location=London}}</ref> | |||
|- | |||
| {{sort|0253983|253,983}}<ref> at Alexa</ref> | |||
| ]<ref>{{cite web |url=http://www.theguardian.com/technology/2013/nov/22/virgin-galactic-bitcoin-space-flights-payment |title=Virgin Galactic to accept Bitcoin for space flights |date=22 November 2013 |accessdate=24 November 2013 |first=Amanda |last=Holpuch |work=The Guardian}}</ref> | |||
|- | |||
| {{sort|0348010|348,010}}<ref> at Alexa</ref> | |||
| ]<ref>{{cite news |author1=Mat 'Inferiorego' Elfring |title=Dynamite Digital Adds Bitcoin Payment Option and Offers Discount Bundle |url=http://www.comicvine.com/articles/dynamite-digital-adds-bitcoin-payment-option-and-o/1100-149863/ |accessdate=27 December 2014 |publisher=CBS Interactive |date=17 September 2014}}</ref> | |||
|- | |||
| {{sort|1145668|1,145,668}}<ref> at Alexa</ref> | |||
| ]<ref>{{cite web |url=http://finance.yahoo.com/news/clearly-canadian-joins-bitcoin-community-110000013.html |title=Clearly Canadian Joins Bitcoin Community |work=finance.yahoo.com |date=23 December 2013 |accessdate=10 February 2014 |publisher=]}}</ref> | |||
|- | |||
| n.a. | |||
| ]<ref>{{cite news |url=http://www.bloomberg.com/news/2014-01-16/how-many-bitcoins-for-a-courtside-seat-.html |title=How Many Bitcoins for a Courtside Seat? |publisher=Bloomberg LP |work=bloomberg.com |date=16 January 2014 |accessdate=20 January 2014 |author=Davidson, Kavitha}}</ref> | |||
|- | |||
|} | |||
=== Acceptance by nonprofits === | |||
The Electronic Frontier Foundation,<ref name="EFF2013" /> ],<ref>{{cite web |url=http://greenpeaceblogs.org/2014/09/22/greenpeace-now-accepting-bitcoin-donations/ |title=Greenpeace now accepting bitcoin donations |author=Cassady Sharp |date=22 September 2014 |accessdate=31 October 2014 |publisher=Greenpeace}}</ref> ],<ref>{{cite news |author1=Emil Protalinski |title=Mozilla's 2013 annual report: Revenue up just 1% to $314M, and again 90% came from Google |url=http://venturebeat.com/2014/11/21/mozilla-releases-annual-report-for-2013-revenue-up-just-1-to-314m-and-again-90-came-from-google/ |accessdate=8 January 2015 |date=21 November 2014}}</ref> and ].<ref>{{cite web |url=http://blog.wikimedia.org/2014/07/30/wikimedia-foundation-now-accepts-bitcoin/ |title=Wikimedia Foundation Now Accepts Bitcoin |publisher=Wikimedia |author=Lisa Gruwell |date=30 July 2014 |accessdate=30 October 2014}}</ref> Some U.S. political candidates, including New York City Democratic Congressional candidate ] have said they would accept campaign donations in bitcoin.<ref>{{cite news |author1=Jaime Fuller |title=Bring the popcorn — here's our guide to the hottest primaries of the summer |url=http://www.washingtonpost.com/blogs/the-fix/wp/2014/06/16/bring-the-popcorn-heres-our-guide-to-the-hottest-primaries-of-the-summer/ |accessdate=8 January 2015 |publisher=Washington Post |date=16 June 2014}}</ref> In late 2013 the ] became the first university in the world to accept bitcoins.<ref>{{cite news |url=http://blogs.wsj.com/moneybeat/2013/11/22/the-university-of-bitcoin-rises-in-cyprus/ |title=The University of Bitcoin Rises in Cyprus |date=22 November 2013 |accessdate=22 November 2013 |first=Paul |last=Vigna |work=The Wall Street Journal}}</ref> | |||
===Payment service providers=== | |||
Merchants accepting bitcoin such as Dish Network corp., use the services of bitcoin payment service providers such as ] or ]. When a customer pays in bitcoin, the payment service provider accepts the bitcoin on behalf of the merchant, directly converts it, and sends the obtained amount to merchant's bank account, charging a fee of less than 1 percent for the service.<ref name="Reutersmerchants">{{cite news |first1=Gertrude |last1=Chavez-Dreyfuss |first2=Michael |last2=Connor |title=Bitcoin shows staying power as online merchants chase digital sparkle |date=28 August 2014 |publisher=Reuters |url=http://www.reuters.com/article/2014/08/28/us-usa-bitcoin-retailers-analysis-idUSKBN0GS0AG20140828 |accessdate=28 August 2014}}</ref> | |||
=== Use in retail transactions === | |||
] | |||
Due to the design of bitcoin, all retail figures are only estimates.<ref name="MIT Technology Review" /><ref name="reutersretail" /> According to Tim Swanson, head of business development at a Hong Kong-based cryptocurrency technology company, in 2014, daily retail purchases made with bitcoin were worth about $2.3 million.<ref name="reutersretail">{{cite news |url=http://www.reuters.com/article/2014/12/11/us-markets-bitcoin-adoption-analysis-idUSKBN0JP2CZ20141211?utm_source=Triggermail&utm_medium=email&utm_term=BII%20List%20Payments%20ALL&utm_campaign=Post%20Blast%20%28bii-payments%29%3A%20Alibaba%20launches%20internet%20bank%20%E2%80%93%20JD.com%20offering%20installment%20loans%20%E2%80%93%20Millennials%20have%20mixed%20reactions%20about%20Bitcoin |title=All the rage a year ago, bitcoin sputters as adoption stalls |publisher=Thompson Reuters |work=reuters.com |quote=bitcoin. |date=11 December 2014 |accessdate=30 June 2015 |author1=Gertrude Chavez-Dreyfuss |author2=Michael Connor |lastauthoramp=yes}}</ref> He estimates that, {{as of|2015|2|lc=y}}, fewer than 5,000 bitcoins per day (worth roughly $1.2 million at the time) were being used for retail transactions,<ref name="MIT Technology Review" /> and concluded that in 2014 "it appears there has been very little if any increase in retail purchases using bitcoin."<ref name="MIT Technology Review" /> | |||
=== Financial institutions === | |||
Bitcoin companies have had difficulty opening traditional bank accounts because lenders have been leery of bitcoin's links to illicit activity.<ref>{{cite news |author1=Robin Sidel |title=Banks Mostly Avoid Providing Bitcoin Services |url=http://www.wsj.com/articles/SB10001424052702304202204579252850121034702 |accessdate=27 December 2014 |publisher=Wallstreet Journal |date=22 December 2013}}</ref> According to ], a co-founder of ], "banks are scared to deal with bitcoin companies, even if they really want to".<ref name=scaredbankers>{{cite news |url=http://www.bloomberg.com/news/2013-12-05/bitcoin-skepticism-by-bankers-from-china-to-u-s-hinders-growth.html |title=Bankers Balking at Bitcoin in U.S. as Real-World Obstacles Mount |publisher=Bloomberg |work=bloomberg.com |date=5 December 2013 |accessdate=16 April 2014 |author=Dougherty, Carter}}</ref> In 2014, the ] closed accounts of businesses with ties to bitcoin,<ref>{{cite web |url=http://www.theguardian.com/world/2014/apr/10/bitcoin-dumped-by-national-australia-bank-as-too-risky |title=Bitcoin firms dumped by National Australia Bank as 'too risky' |publisher=The Guardian |work=Australian Associated Press |date=10 April 2014 |accessdate=23 February 2015}}</ref> and ] refused to serve a hedge fund with links to bitcoin.<ref>{{cite web |url=http://www.bbc.com/news/world-europe-jersey-30261976 |title=HSBC severs links with firm behind Bitcoin fund |publisher=BBC |work=bbc.com |date=1 December 2014 |accessdate=9 January 2015 |author=Weir, Mike}}</ref> Australian banks in general have been reported as closing down bank accounts of operators of businesses involving the currency;<ref name="afr.com">{{Cite web |title=ACCC investigating why banks are closing bitcoin companies' accounts |url=http://www.afr.com/technology/accc-investigating-why-banks-are-closing-bitcoin-companies-accounts-20151018-gkc5iv |website=Financial Review|access-date = 28 January 2016 |language=en-US}}</ref> this has become the subject of an investigation by the ].<ref name="afr.com" /> Nonetheless, Australian banks have keenly adopted the blockchain technology on which bitcoin is based.<ref>{{Cite web |title=CBA tests blockchain trading with 10 global banks |url=http://www.smh.com.au/business/banking-and-finance/commonwealth-bank-of-australia-tests-blockchain-trading-with-10-global-banks-20160120-gmalvp.html |website=The Sydney Morning Herald|access-date = 28 January 2016}}</ref> | |||
In a 2013 report, Bank of America Merrill Lynch stated that "we believe bitcoin can become a major means of payment for e-commerce and may emerge as a serious competitor to traditional money-transfer providers."<ref name=ForbesDec>{{cite news |last=Hill |first=Kashmir |title=Bitcoin Valued At $1300 By Bank of America Analysts |url=http://www.forbes.com/sites/kashmirhill/2013/12/05/bank-of-america-analysts-say-bitcoins-value-is-1300/ |accessdate=23 March 2014 |newspaper=Forbes.com |date=5 December 2013}}</ref> | |||
In June 2014, the first bank that converts deposits in currencies instantly to bitcoin without any fees was opened in Boston.<ref>{{cite news |title=Bitcoin: is Circle the world's first crypto-currency bank? |url=http://www.theweek.co.uk/world-news/bitcoin/56138/bitcoin-passes-1000-mark-will-it-take-over-world |accessdate=13 June 2014 |work=The week.co.uk |date=16 May 2014}}</ref> | |||
=== As an investment === | |||
Some Argentinians have bought bitcoins to protect their savings against high inflation or the possibility that governments could confiscate savings accounts.<ref name="5facts" /> During the ], bitcoin purchases in Cyprus rose due to fears that savings accounts would be confiscated or taxed.<ref name="BloombergCyprus">{{cite news |last=Salyer |first=Kirsten |title=Fleeing the Euro for Bitcoins |url=http://www.bloomberg.com/news/2013-03-20/fleeing-the-euro-for-bitcoins-.html |publisher=Bloomberg L.P. |date=20 March 2013 |accessdate=31 October 2014 |deadurl=no}}</ref> | |||
Other methods of investment are bitcoin funds. The first regulated bitcoin fund was established in Jersey in July 2014 and approved by the Jersey Financial Services Commission.<ref name="BitcoinJersey">{{cite news |title=Jersey approve Bitcoin fund launch on island |url=http://www.bbc.com/news/world-europe-jersey-28247796 |date=10 July 2014 |accessdate=10 July 2014 |publisher=BBC news}}</ref> Also, c. 2012 an attempt was made by the ] (who in April 2013 claimed they owned nearly 1% of all bitcoins in existence<ref>{{cite news |title=Never Mind Facebook; Winklevoss Twins Rule in Digital Money |author1=Nathaniel Popper |author2=Peter Lattman |lastauthoramp=yes |url=http://dealbook.nytimes.com/2013/04/11/as-big-investors-emerge-bitcoin-gets-ready-for-its-close-up/ |publisher=The New York Times |date=11 April 2013 |accessdate=31 October 2014}}</ref>) to establish a bitcoin ].<ref name=winkles>{{cite news |url=http://blogs.wsj.com/moneybeat/2013/07/02/beware-the-risks-of-the-bitcoin-winklevii-outline-the-downside/ |title=Beware the Risks of the Bitcoin: Winklevii Outline the Downside |publisher=The Wall Street Journal |work=Moneybeat |date=2 July 2013 |accessdate=21 October 2013 |author=Grocer, Stephen}}</ref> As of early 2015, they have announced plans to launch a New York-based bitcoin exchange named Gemini,<ref>{{cite news |url=http://dealbook.nytimes.com/2015/01/22/winklevoss-twins-aim-to-take-bitcoin-mainstream-with-a-regulated-exchange/?_r=0 |title=Winklevoss Twins aim to take Bitcoin Mainstream |publisher=The New York Times |work=Dealbook blog |date=23 January 2015 |accessdate=15 February 2015 |author1=Popper, N. |author2=Ember, S. |lastauthoramp=yes}}</ref> which has received approval to launch on 5 October 2015.<ref>{{cite news |last1=Tepper |first1=Fitz |title=Winklevoss Twins Receive Approval To Launch Bitcoin Exchange Gemini |url=http://techcrunch.com/2015/10/05/winklevoss-twins-receive-approval-to-launch-bitcoin-exchange-gemini/ |accessdate=22 November 2015 |publisher=TechCrunch |date=5 October 2015}}</ref> On 4 May 2015, Bitcoin Investment Trust started trading on the OTCQX market as GBTC.<ref>{{cite news |last1=Curran |first1=Rob |title=A Bitcoin Fund Is Born, With Teething Pains |url=http://www.wsj.com/articles/a-bitcoin-fund-is-born-with-teething-painsa-bitcoin-fund-is-born-with-teething-pains-1435601798 |accessdate=22 November 2015 |work=Markets |publisher=] |date=6 July 2015}}</ref> Forbes started publishing arguments in favor of investing in December 2015.<ref>{{cite news |publisher=Forbes |date=11 December 2015 |accessdate=12 December 2015 |url=http://www.forbes.com/sites/laurashin/2015/12/11/should-you-invest-in-bitcoin-10-arguments-in-favor-as-of-december-2015/ |first=Laura |last=Shin |title=Should You Invest In Bitcoin? 10 Arguments In Favor As Of December 2015}}</ref> | |||
In 2013 and 2014, the ]<ref name="ebawarn">{{cite web|url=http://www.eba.europa.eu/documents/10180/16136/EBA+Warning+on+Virtual+Currencies.pdf |archiveurl=http://www.webcitation.org/6MCBOsSXG?url=http%3A%2F%2Fwww.eba.europa.eu%2Fdocuments%2F10180%2F16136%2FEBA%2BWarning%2Bon%2BVirtual%2BCurrencies.pdf |archivedate=28 December 2013 |title=Warning to consumers on virtual currencies |publisher=European Banking Authority |date=12 December 2013 |accessdate=23 December 2013 |deadurl=yes |df=dmy }}</ref> and the ] (FINRA), a United States ],<ref name="finrawarn">{{cite news |url=http://www.reuters.com/article/2014/03/11/us-bitcoin-finra-idUSBREA2A1OJ20140311 |title=Beware Bitcoin: U.S. brokerage regulator. |author=Jonathan Stempel |date=11 March 2014 |accessdate=14 March 2014 |publisher=reuters.com}}</ref> warned that investing in bitcoins carries significant risks. Forbes named bitcoin the best investment of 2013.<ref>{{Cite news |url=http://www.forbes.com/sites/kashmirhill/2013/12/26/how-you-should-have-spent-100-in-2013-hint-bitcoin/ |title=How You Should Have Spent $100 In 2013 (Hint: Bitcoin) |last=Hill |first=Kashmir |date= |work=Forbes|access-date = 16 February 2015}}</ref> In 2014, Bloomberg named bitcoin one of its worst investments of the year.<ref name=worst>{{cite news |url=http://www.bloomberg.com/news/2014-12-22/the-best-and-worst-investments-of-2014.html |title=The Best and Worst Investments of 2014 |publisher=Bloomberg LP |work=bloomberg.com |date=23 December 2014 |accessdate=9 January 2015 |author=Steverman, Ben}}</ref> In 2015, bitcoin topped Bloomberg's currency tables.<ref>{{cite news |last1=Gilbert |first1=Mark |title=Bitcoin Won 2015. Apple … Did Not |url=http://www.bloombergview.com/articles/2015-12-29/bitcoin-won-in-2015-but-apple-lost-big |accessdate=29 December 2015 |publisher=Bloomberg |date=29 December 2015}}</ref> | |||
To improve access to price information and increase transparency, on 30 April 2014 ] announced plans to list prices from bitcoin companies ] and ] on its 320,000 subscription financial data terminals.<ref name=wsjprice>{{cite news |title=Bloomberg to List Bitcoin Prices, Offering Key Stamp of Approval |url=http://online.wsj.com/news/articles/SB10001424052702304893404579532471795644350?mg=reno64-wsj&url=http%3A%2F%2Fonline.wsj.com%2Farticle%2FSB10001424052702304893404579532471795644350.html |accessdate=23 March 2015 |newspaper=WSJ |date=30 April 2014 |author=Michael J. Casey}}</ref><ref name=cnbcprice>{{cite news |title=Bloomberg terminal now following bitcoin prices |url=http://www.cnbc.com/id/101628763 |accessdate=23 March 2015 |date=30 April 2014 |author=CNBC}}</ref> In May 2015, Intercontinental Exchange Inc., parent company of the ], announced a bitcoin index initially based on data from ] transactions.<ref name="NYSE index">{{cite web |url=http://www.businesswire.com/news/home/20150519005701/en#.VV-cNkhM6HD |title=NYSE to Launch NYSE Bitcoin Index, NYXBT |publisher=Business Wire |work=businesswire.com |date=19 May 2015 |accessdate=22 May 2015}}</ref> | |||
=== Venture capital === | |||
]ists, such as ]'s ], which invested {{currency|3|USD}} million in ], do not purchase bitcoins themselves, instead funding bitcoin infrastructure like ] that provide payment systems to merchants, exchanges, wallet services, etc.<ref name="mtr20130612">{{cite news |url=http://www.technologyreview.com/news/515391/bitcoin-millionaires-become-investing-angels/ |title=Bitcoin Millionaires Become Investing Angels |work=Computing News |publisher=] |date=12 June 2013 |accessdate=13 June 2013 |author=Simonite, Tom}}</ref> In 2012, an incubator for bitcoin-focused start-ups was founded by Adam Draper, with financing help from his father, venture capitalist ], one of the largest bitcoin holders after winning an auction of 30,000 bitcoins,<ref name=wsj1214>{{cite news |author1=Robin Sidel |title=Ten-hut! Bitcoin Recruits Snap To |url=http://www.wsj.com/news/articles/SB21659981523255993497704580305120918936264?mg=reno64-wsj&url=http%3A%2F%2Fonline.wsj.com%2Farticle%2FSB21659981523255993497704580305120918936264.html |accessdate=9 December 2014 |work=Wall Street Journal |publisher=Dow Jones & Company |date=1 December 2014}}</ref> at the time called 'mystery buyer'.<ref name=guard714>{{cite news |title=Silk Road's legacy 30,000 bitcoin sold at auction to mystery buyers |author=Alex Hern |url=http://www.theguardian.com/technology/2014/jul/01/silk-road-bitcoin-auction |publisher=The Guardian |date=1 July 2014 |accessdate=31 October 2014}}</ref> The company's goal is to fund 100 bitcoin businesses within 2–3 years with $10,000 to $20,000 for a 6% stake.<ref name="wsj1214" /> Investors also invest in bitcoin mining.<ref>{{cite news |url=http://www.redherring.com/finance/coinseed-raises-7-5m-invests-5m-in-bitcoin-mining-hardware-investment-round-up/ |title=CoinSeed raises $7.5m, invests $5m in Bitcoin mining hardware – Investment Round Up |work=Red Herring |date=24 January 2014 |accessdate=9 March 2014}}</ref> According to a 2015 study by Paolo Tasca, bitcoin startups raised almost $1 billion in three years (Q1 2012 – Q1 2015).<ref>{{cite journal |last1=Tasca |first1=Paolo |title=Digital Currencies: Principles, Trends, Opportunities, and Risks |date=7 September 2015 |url=http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2657598 |accessdate=22 January 2016 |publisher=Social Science Research Network}}</ref> | |||
=== Political economy === | |||
The decentralization of money offered by virtual currencies like bitcoin has its theoretical roots in the ],<ref>{{cite web |url=http://www.forbes.com/sites/jonmatonis/2012/11/03/ecb-roots-of-bitcoin-can-be-found-in-the-austrian-school-of-economics/ |title=ECB: "Roots Of Bitcoin Can Be Found In The Austrian School Of Economics" |publisher=Forbes |first=Jon |last=Matonis |date=3 November 2012 |accessdate=18 September 2015}}</ref> especially with ] in his book ''Denationalisation of Money: The Argument Refined'', in which he advocates a complete ] in the production, distribution and management of money to end the monopoly of ].<ref>{{cite book |title=Denationalisation of Money: The Argument Refined |date=October 1976 |publisher=The institute of economic affairs |location=2 Lord North Street, Westminster, London SWIP 3LB |isbn=0-255 36239-0 |url=http://nakamotoinstitute.org/static/docs/denationalisation.pdf |format=PDF |author=] |accessdate=10 September 2015}}</ref> | |||
Bitcoin appeals to tech-savvy ]s, because it so far exists outside the institutional banking system and the control of governments.<ref name=nation>{{cite news |url=http://www.thenation.com/article/179620/bitcoin-future-money?page=full |title=Bitcoin the Future of Money? |author=Doug Henwood |date=19 May 2014 |publisher=The Nation.com |accessdate=12 September 2014}}</ref> However, researchers looking to uncover the reasons for interest in bitcoin did not find evidence in Google search data that this was linked to libertarianism.<ref name=uok>{{cite journal |url=http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2518603 |title=Characteristics of Bitcoin Users: An Analysis of Google Search Data |author1=Matthew Graham Wilson |author2=Aaron Yelowitz |lastauthoramp=yes |journal=Social Science Research Network |date=November 2014 |volume=Working Papers Series}}</ref> | |||
Bitcoin's appeal reaches from ] critics, "who perceive the state and banking sector as representing the same elite interests, recognising in it the potential for collective ] governance of currency"<ref>{{cite web |url=http://www.e-ir.info/2014/06/01/visions-of-a-techno-leviathan-the-politics-of-the-bitcoin-blockchain/ |title=Visions of a Techno-Leviathan: The Politics of the Bitcoin Blockchain |author=Brett Scott |date=1 June 2014 |publisher=E-International Relations |accessdate=31 October 2014}}</ref> and socialists proposing their "own states, complete with currencies",<ref>{{cite web |url=http://internationalsocialistnetwork.org/index.php/ideas-and-arguments/301-mistress-magpie-a-left-defence-of-bitcoin |title=A left defence of Bitcoin |publisher=International Socialist Network |date=December 2013 |author=Margaret Corvid |accessdate=31 October 2014}}</ref> to ] critics suspicious of ], at a time when activities within the regulated banking system were responsible for the severity of the ],<ref>{{cite web |url=http://ssrn.com/abstract=2218812 |author=Melanie L. Fein |title=The Shadow Banking Charade |date=15 February 2013 |accessdate=31 October 2014}}</ref> "because governments are not fully living up to the responsibility that comes with state-sponsored money".<ref>{{cite news |url=http://www.breakingviews.com/edward-hadas-bitcoin-is-a-step-back-not-forward/21121998.article |title=Right-wing dreams |author=Edward Hadas |date=27 November 2013 |publisher=Thomson Reuters |accessdate=31 October 2014}}</ref> | |||
Bitcoin has been described as "remov the imbalance between the big boys of finance and the disenfranchised little man, potentially allowing early adopters to negotiate favourable rates on exchanges and transfers – something that only the very biggest firms have traditionally enjoyed".<ref>{{cite news |last1=Hamill |first1=Jasper |title=Native American Activist Wants To Swap The Dollar For Bitcoin |url=http://www.forbes.com/sites/jasperhamill/2013/12/19/native-american-activist-wants-to-swap-the-dollar-for-bitcoin/ |accessdate=1 October 2014 |work=Forbes |date=19 December 2013}}</ref> Two WSJ journalists describe bitcoin in their book as "about freeing people from the tyranny of centralised trust".<ref>{{cite news |author1=Staff |title=Much more than digital cash |url=http://www.economist.com/news/business-books-quarterly/21638093-rise-and-fall-crypto-currency-good-news-authors-least-much |accessdate=13 January 2015 |work=The Economist |publisher=The Economist Newspaper Ltd |date=10 January 2015}}</ref> | |||
== Legal status and regulation == | |||
{{Main article|Legality of bitcoin by country}} | |||
The legal status of bitcoin varies substantially from country to country and is still undefined or changing in many of them. While some countries have explicitly allowed its use and trade, others have banned or restricted it. Likewise, various government agencies, departments, and courts have classified bitcoins differently. Regulations and bans that apply to bitcoin probably extend to similar ] systems.<ref>{{cite journal |last1=Tasca |first1=Paolo |title=Digital Currencies: Principles, Trends, Opportunities, and Risks |date=7 September 2015 |doi= |url=http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2657598 |accessdate=21 January 2016 |publisher=Social Science Research Network}}</ref> | |||
In April 2013, ], a Harvard public policy professor, suggested that governments could outlaw bitcoin,<ref>{{cite news |url=http://www.huffingtonpost.com/steven-strauss/bitcoin_b_3081812.html |title=Nine Trust-Based Problems With Bitcoin |work=The Huffington Post |date=14 April 2013 |accessdate=20 October 2013 |last=Strauss |first=Steven}}</ref> and this possibility was mentioned again by a bitcoin investment vehicle in a July 2013 report to a regulator.<ref name="winkles"/> However, the vast majority of nations have not done so as of 2014. It is illegal in Bangladesh,<ref name=bangla>{{cite news |url=http://www.telegraph.co.uk/finance/currency/11097208/Why-Bangladesh-will-jail-Bitcoin-traders.html |title=Why Bangladesh will jail Bitcoin traders |publisher=The Telegraph |work=telegraph.co.uk |date=15 September 2014 |accessdate=23 February 2015 |author=AFP |location=London}}</ref> Bolivia,<ref name=bol>{{cite web |url=http://www.ibtimes.co.uk/cryptocurrency-round-bolivian-bitcoin-ban-ios-apps-dogecoin-mcdonalds-1453453 |title=Cryptocurrency Round-Up: Bolivian Bitcoin Ban, iOS Apps & Dogecoin at McDonald's |publisher=International Business Times |work=ibtimes.co.uk |date=20 June 2014 |accessdate=23 February 2015 |author=Cuthbertson, Anthony}}</ref> Ecuador.<ref name="ecuador">{{cite web |url=http://www.ibtimes.co.uk/ecuador-reveals-national-digital-currency-plans-following-bitcoin-ban-1463397 |title=Ecuador Reveals National Digital Currency Plans Following Bitcoin Ban |publisher=International Business Times |work=ibtimes.co.uk |date=1 September 2014 |accessdate=23 February 2015 |author=Cuthbertson, Anthony}}</ref> | |||
In China in December 2013 the Chinese government declared that "bitcoin is not a currency and should not be circulated and used in the market as a currency." 'While people there are free to buy and sell it, financial institutions have been warned away'.<ref>http://www.forbes.com/sites/kashmirhill/2014/01/31/bitcoins-legality-around-the-world/#7b4cc5a079b2 Retrieved September-18-2016</ref> | |||
== Criminal activity == | |||
The use of bitcoin by criminals has attracted the attention of financial regulators, legislative bodies, law enforcement, and the media.<ref name="Lavin, Tim">{{cite news |url=http://www.bloombergview.com/articles/2013-08-08/did-the-sec-just-validate-bitcoin-no- |title=The SEC Shows Why Bitcoin Is Doomed |publisher=Bloomberg LP |work=bloomberg.com |date=8 August 2013 |accessdate=20 October 2013 |author=Lavin, Tim}}</ref> The FBI prepared an intelligence assessment,<ref name="fbi_report">{{cite news |url=http://www.wired.com/images_blogs/threatlevel/2012/05/Bitcoin-FBI.pdf |title=Bitcoins Virtual Currency: Unique Features Present Challenges for Deterring Illicit Activity |publisher=FBI |work=Cyber Intelligence Section and Criminal Intelligence Section |date=24 April 2012 |accessdate=2 November 2014}}</ref> the SEC has issued a pointed warning about investment schemes using virtual currencies,<ref name="Lavin, Tim" /> and the U.S. Senate held a hearing on virtual currencies in November 2013.<ref name="USoff" /> | |||
Several news outlets have asserted that the popularity of bitcoins hinges on the ability to use them to purchase illegal goods.<ref name=Monetarists>{{cite news |url=http://www.economist.com/node/21563752 |title=Monetarists Anonymous |publisher=The Economist Newspaper Limited |work=The Economist |date=29 September 2012 |accessdate=21 October 2013}}</ref><ref>{{cite web |url=http://www.theguardian.com/world/2013/mar/22/silk-road-online-drug-marketplace |title=Silk Road: the online drug marketplace that officials seem powerless to stop |publisher=Guardian News and Media Limited |work=theguardian.com |date=22 March 2013 |accessdate=20 October 2013 |author=Ball, James}}</ref> In 2014, researchers at the University of Kentucky found "robust evidence that computer programming enthusiasts and illegal activity drive interest in bitcoin, and find limited or no support for political and investment motives."<ref name=uok /> | |||
===Funding Terrorism === | |||
Bitcoin is transparent in its reporting of how much gets transferred and when, but lacks oversight about reporting suspicious activities in comparison to the regulated banking system. Bitcoin provides 'cover' to 'move money around without triggering the usual alarm bells associated with giant transfers of cash.' ], former head of the ]'s ] (FinCEN), an agency that fights ] and terrorist finance, has stated that 'powerful payment technologies could facilitate bad actors.' She stated that "What keeps me up at night when I am thinking about digital currency…the real threats out there, these days we’re thinking a lot about ]," Calvery said. "How they’re moving their money, and how potential US-based individuals are becoming foreign fighters: Are they moving their money, can we identify them from the movement of their money? What does it mean if they start moving their money through bitcoin? We’ve started to see some public articles suggesting that has occurred." | |||
<ref>http://www.defenseone.com/threats/2015/02/terrorism-finance-trackers-worry-isis-already-using-bitcoin/105345/ Retrieved October-7-3016</ref> | |||
=== Theft === | |||
There have been many cases of bitcoin theft.<ref name="Economist113013Pressure" /> One way this is accomplished involves a third party accessing the private key to a victim's bitcoin address,<ref>{{cite news |last=Jeffries |first=Adrianne |title=How to steal Bitcoin in three easy steps |date=19 December 2013 |url=http://www.theverge.com/2013/12/19/5183356/how-to-steal-bitcoin-in-three-easy-steps |work=The Verge |accessdate=17 January 2014}}</ref> or of an online wallet.<ref>{{cite news |last=Everett |first=David |title=So how can you steal Bitcoins |url=http://www.smartcard.co.uk/articles/so_how_can_you_steal_bitcoins.php |work=Smartcard & Identity News |accessdate=17 January 2014 |date=April 2012}}</ref> If the private key is stolen, all the bitcoins from the compromised address can be transferred. In that case, the network does not have any provisions to identify the thief, block further transactions of those stolen bitcoins, or return them to the legitimate owner.<ref name="winkles" /> | |||
Theft also occurs at sites where bitcoins are used to purchase illicit goods. In late November 2013, an estimated $100 million in bitcoins were allegedly stolen from the online illicit goods marketplace ], which immediately closed.<ref name="hern2013" /> Users tracked the coins as they were processed and converted to cash, but no funds were recovered and no culprits identified.<ref name="hern2013">{{cite news |url=http://www.theguardian.com/technology/2013/dec/09/recovering-stolen-bitcoin-sheep-marketplace-trading-digital-currency-money |title=Recovering stolen bitcoin: a digital wild goose chase |work=The Guardian |date=9 December 2013 |first=Alex |last=Hern |accessdate=6 March 2014}}</ref> A different black market, Silk Road 2, stated that during a February 2014 hack, bitcoins valued at $2.7 million were taken from escrow accounts.<ref name="silk2">{{cite news |url=http://www.bbc.co.uk/news/technology-26187725 |title=Silk Road 2 loses $2.7m in bitcoins in alleged hack |work=BBC News |date=14 February 2014 |accessdate=15 February 2014}}</ref> | |||
Sites where users exchange bitcoins for cash or store them in "wallets" are also targets for theft. Inputs.io, an Australian wallet service, was hacked twice in October 2013 and lost more than $1 million in bitcoins.<ref>{{Cite news |url=http://www.theguardian.com/technology/2013/nov/08/hackers-steal-1m-from-bitcoin-tradefortress-site |title=Bitcoin site Inputs.io loses £1m after hackers strike twice |last=Hern |first=Alex |work=|access-date = 18 September 2015 |date=8 November 2013 |publisher=The Guardian}}</ref> In late February 2014 ], one of the largest virtual currency exchanges, filed for bankruptcy in Tokyo amid reports that bitcoins worth $350 million had been stolen.<ref name="GoxBankrupt" /> Flexcoin, a bitcoin storage specialist based in ], shut down on March 2014 after saying it discovered a theft of about $650,000 in bitcoins.<ref name="ligaya2014">{{cite news |work=Financial Post |url=http://business.financialpost.com/2014/03/05/after-albertas-flexcoin-mt-gox-hacked-bitcoin-businesses-face-sting-of-free-wheeling-ways/ |title=After Alberta's Flexcoin, Mt. Gox hacked, Bitcoin businesses face sting of free-wheeling ways |date=5 March 2014 |first=Armina |last=Ligaya |accessdate=7 March 2014}}</ref> Poloniex, a digital currency exchange, reported on March 2014 that it lost bitcoins valued at around $50,000.<ref name="truong2014">{{cite news |url=http://www.fastcompany.com/3027373/fast-feed/another-bitcoin-exchange-another-heist |title=Another Bitcoin exchange, another heist |first=Alice |last=Truong |work=Fast Company |date=6 March 2014 |accessdate=7 March 2014}}</ref> | |||
In January 2015 UK-based ], the third busiest bitcoin exchange globally, was hacked and $5 million in bitcoins were stolen.<ref>{{cite web |author1=Zack Whittaker |title=Bitstamp exchange hacked, $5M worth of bitcoin stolen |url=http://www.zdnet.com/article/bitstamp-bitcoin-exchange-suspended-amid-hack-concerns-heres-what-we-know/ |website=Zdnet |publisher=CBS Interactive. |accessdate=6 January 2015 |date=5 January 2015}}</ref> February 2015 saw a Chinese exchange named BTER lose bitcoins worth nearly $2 million to hackers.<ref>{{cite web |url=https://www.techinasia.com/bitcoins-lost-after-china-cryptocurrency-exchange-hack-bter/ |title=Nearly $2M in bitcoins feared lost after Chinese cryptocurrency exchange hack |publisher=Tech In Asia |work=techinasia.com |date=16 February 2015 |accessdate=18 February 2015 |author=Millward, Steven}}</ref> | |||
A major bitcoin exchange, ], was hacked and nearly 120,000 bitcoins (around $60m) was stolen in 2016. Bitfinex was forced to suspend its trading. The theft is the second largest bitcoin heist ever, dwarfed only by Mt. Gox theft in 2014. According to ''Forbes'', "All of Bitfinex's customers,... will stand to lose money. The company has announced a haircut of 36.067% across the board."<ref name="bitfinexheist" /> | |||
=== Black markets === | |||
{{Main article|Darknet market}} | |||
A ] researcher estimated that in 2012, 4.5% to 9% of all transactions on all exchanges in the world were for drug trades on a single ] drugs market, ].<ref name="cmacademic">{{cite conference |url=http://www.andrew.cmu.edu/user/nicolasc/publications/Christin-WWW13.pdf |title=Traveling the Silk Road: A Measurement Analysis of a Large Anonymous Online Marketplace |publisher=Carnegie Mellon INI/CyLab |accessdate=22 October 2013 |author=Christin, Nicolas |year=2013 |page=8 |quote=we suggest to compare the estimated total volume of Silk Road transactions with the estimated total volume of transactions at all Bitcoin exchanges (including Mt.Gox, but not limited to it). The latter corresponds to the amount of money entering and leaving the Bitcoin network, and statistics for it are readily available... approximately 1,335,580 BTC were exchanged on Silk Road... approximately 29,553,384 BTC were traded in Bitcoin exchanges over the same period... The only conclusion we can draw from this comparison is that Silk Road-related trades could plausibly correspond to 4.5% to 9% of all exchange trades}}</ref> Child pornography,<ref name="notonly" /> murder-for-hire services,<ref>{{cite web |url=http://www.thedailybeast.com/articles/2013/10/17/hitman-network-says-it-accepts-bitcoins-to-murder-for-hire.html |title=Hitman Network Says It Accepts Bitcoins to Murder for Hire |publisher=The Daily Beast Company LLC |work=The Daily Beast |date=17 October 2013 |accessdate=17 February 2015 |author=Lake, Eli}}</ref> and weapons<ref>{{cite news |url=http://www.huffingtonpost.com/2013/04/15/bitcoin-guns_n_3070828.html |title=How Bitcoin Sales Of Guns Could Undermine New Rules |publisher=TheHuffingtonPost.com, Inc. |work=huffingtonpost.com |date=15 April 2013 |accessdate=20 October 2013 |author=Smith, Gerry}}</ref> are also allegedly available on black market sites that sell in bitcoin. Due to the anonymous nature and the lack of central control on these markets, it is hard to know whether the services are real or just trying to take the bitcoins.<ref>{{citation |url=http://www.forbes.com/sites/alexknapp/2015/01/19/faking-murders-and-stealing-bitcoin-why-the-silk-road-is-the-strangest-crime-story-of-the-decade/ |accessdate=2 January 2016 |title=Faking Murders And Stealing Bitcoin: Why The Silk Road Is The Strangest Crime Story Of The Decade |date=19 January 2015 |work=Forbes |last1=Alex |first1=Knapp}}</ref> | |||
Several deep web black markets have been shut by authorities. In October 2013 Silk Road was shut down by U.S. law enforcement<ref name=Greenberg>{{cite news |url=http://www.forbes.com/sites/andygreenberg/2013/10/25/fbi-says-its-seized-20-million-in-bitcoins-from-ross-ulbricht-alleged-owner-of-silk-road/ |title=FBI Says It's Seized $28.5 Million In Bitcoins From Ross Ulbricht, Alleged Owner Of Silk Road |author=Andy Greenberg |publisher=Forbes.com |format=blog |date=23 October 2013 |accessdate=24 November 2013}}</ref><ref name="Kelion, Leo">{{cite news |url=http://www.bbc.co.uk/news/technology-26158012 |title=Five arrested in Utopia dark net marketplace crackdown |publisher=BBC |work=bbc.co.uk |date=12 February 2014 |accessdate=13 February 2014 |author=Kelion, Leo}}</ref><ref>{{cite news |publisher=The Guardian |title=Bitcoin price plummets after Silk Road closure |author=Alex Hern |quote=Digital currency loses quarter of value after arrest of Ross Ulbricht, who is accused of running online drugs marketplace |date=3 October 2013 |url=http://www.theguardian.com/technology/2013/oct/03/bitcoin-price-silk-road-ulbricht-value |accessdate=31 October 2014}}</ref> leading to a short-term decrease in the value of bitcoin.<ref>{{cite news |url=http://www.wired.com/2013/10/bitcoin-market-drops-600-million-on-silk-road-bust/ |title=Bitcoin Values Plummet $500M, Then Recover, After Silk Road Bust |author=Robert McMillan |date=2 October 2013 |publisher=Wired |accessdate=31 October 2014}}</ref> In 2015, the founder of the site was sentenced to life in prison.<ref>{{cite web |url=http://www.bbc.com/news/world-us-canada-32941060 |title=Silk Road drug website founder Ross Ulbricht jailed |publisher=BBC |work=BBC News |date=29 May 2015 |accessdate=30 May 2015}}</ref> Alternative sites were soon available, and in early 2014 the ] reported that the closure of Silk Road had little impact on the number of Australians selling drugs online, which had actually increased.<ref>{{cite news |url=http://www.abc.net.au/news/2014-03-31/online-drug-trade-soaring-experts-say/5354930 |publisher=ABC News |title=Silk Road closure fails to dampen illegal drug sales online, experts say |author=Katie Silver |date=31 March 2014 |accessdate=31 October 2014}}</ref> In early 2014, Dutch authorities closed Utopia, an online illegal goods market, and seized 900 bitcoins.<ref>{{cite news |url=http://www.independent.co.uk/life-style/gadgets-and-tech/utopia-no-more-drug-marketplace-seen-as-the-next-silk-road-shut-down-by-dutch-police-9126063.html |title=Utopia no more: Drug marketplace seen as the next Silk Road shut down by Dutch police |publisher=independent.co.uk |work=The Independent |date=13 February 2014 |accessdate=8 November 2014 |author=Sophie Murray-Morris |location=London}}</ref> In late 2014, a joint police operation saw European and American authorities seize bitcoins and close 400 deep web sites including the illicit goods market Silk Road 2.0.<ref>{{cite web |url=http://www.bbc.com/news/technology-29950946 |title=Huge raid to shut down 400-plus dark net sites |publisher=BBC |work=bbc.com |date=7 November 2014 |accessdate=8 November 2014 |author=Wakefield, Jane}}</ref> Law enforcement activity has resulted in several convictions. In December 2014, ] was sentenced to two years in prison for indirectly helping to send $1 million to the Silk Road drugs site,<ref>{{cite news |author1=Nate Raymond |title=Bitcoin backer gets two years prison for illicit transfers |url=http://www.reuters.com/article/2014/12/19/us-usa-crime-bitcoin-idUSKBN0JX2CW20141219 |accessdate=20 December 2014 |work=Reuters |publisher=Thompson Reuters |date=19 December 2014}}</ref> and in February 2015, its founder, ], was convicted on drugs charges and faces a life sentence.<ref>{{cite web |url=http://www.bbc.com/news/world-us-canada-31134938 |title=Ross Ulbricht: Silk Road creator convicted on drugs charges |publisher=BBC |date=5 February 2015 |accessdate=17 February 2015}}</ref> | |||
Some black market sites may seek to steal bitcoins from customers. The bitcoin community branded one site, Sheep Marketplace, as a scam when it prevented withdrawals and shut down after an alleged bitcoins theft.<ref name="techienews">{{cite web |url=http://www.techienews.co.uk/973470/silk-road-like-sheep-marketplace-scams-users-39k-bitcoins-worth-40-million-stolen/ |title=Silk Road-like Sheep Marketplace scams users; over 39k Bitcoins worth $40 million stolen |author=Ravi Mandalia |publisher=Techie News |date=1 December 2013 |accessdate=2 December 2013}}</ref> In a separate case, escrow accounts with bitcoins belonging to patrons of a different black market were hacked in early 2014.<ref name=silk2 /> | |||
According to the ], a UK-based charity, bitcoin is used to purchase child pornography, and almost 200 such websites accept it as payment. Bitcoin isn't the sole way to purchase child pornography online, as Troels Oertling, head of the cybercrime unit at ], states, "Ukash and Paysafecard... have been used to pay for such material." However, the Internet Watch Foundation lists around 30 sites that exclusively accept bitcoins.<ref name=notonly>{{cite news |url=http://www.bloomberg.com/news/articles/2014-10-09/bitcoin-payments-by-pedophiles-frustrate-child-porn-fight |title=Bitcoin Payments by Pedophiles Frustrate Child Porn Fight |publisher=Bloomberg LP |work=BloombergBusiness |date=10 October 2014 |accessdate=16 February 2015 |author=Schweizer, Kristen}}</ref> Some of these sites have shut down, such as a deep web ] website that aimed to fund the creation of new child porn.<ref>{{Cite news |url=http://www.deepdotweb.com/2014/11/09/as-drug-markets-are-seized-pedophiles-launch-a-crowdfunding-site/ |title=While Markets Get Seized: Pedophiles Launch a Crowdfunding Site |date= |work=|access-date = 19 February 2015}}</ref>{{better source|date=September 2015}} Furthermore, hyperlinks to child porn websites have been added to the blockchain as arbitrary data can be included when a transaction is made.<ref>{{cite web |url=http://www.dailydot.com/business/bitcoin-child-porn-transaction-code/ |title=If you own Bitcoin, you also own links to child porn |work=The Daily Dot |date=7 May 2013 |accessdate=16 February 2015 |author=Hopkins, Curt}}</ref><ref>{{cite web |url=http://eandt.theiet.org/magazine/2015/02/in-blocks-we-trust.cfm |title=As Bitcoin slides, the Blockchain grows |date= |accessdate= |website= |publisher=IET Engineering and Technology Magazine |last=Bradbury |first=Danny}}</ref> | |||
=== Money laundering === | |||
Bitcoins may not be ideal for money laundering because all transactions are public.<ref name="FistfulPaper201308">{{cite news |url=http://www.pcworld.com/article/2047608/bitcoin-offers-privacy-as-long-as-you-dont-cash-out-or-spend-it.html |title=Bitcoin offers privacy-as long as you don't cash out or spend it |last=Kirk |first=Jeremy |date=28 August 2013 |work=PC World |accessdate=31 October 2014}}</ref> Authorities, including the ]<ref name="ebawarn" /> the FBI,<ref name="fbi_report" /> and the ] of the ]<ref name=fatf>{{cite web |url=http://www.fatf-gafi.org/media/fatf/documents/recommendations/Guidance-RBA-NPPS.pdf |title=Guidance for a Risk-Based Approach: Prepaid Cards, Mobile Payments and Internet-based Payment Services |work=Guidance for a risk-based approach |publisher=Financial Action Task Force (FATF) |accessdate=6 March 2014 |location=Paris |page=47 |format=PDF |date=June 2013}}</ref> have expressed concerns that bitcoin may be used for money laundering. In early 2014, an operator of a U.S. bitcoin exchange was arrested for money laundering.<ref name=vchair>{{cite news |url=http://www.bbc.co.uk/news/technology-25919482 |title=US makes Bitcoin exchange arrests after Silk Road closure |publisher=BBC |work=bbc.co.uk |date=27 January 2014 |accessdate=28 January 2014 |author=Lee, Dave}}</ref> A report by UK's ] and ] named "UK national risk assessment of money laundering and terrorist financing" (2015 October) found that, of the twelve methods examined in the report, bitcoin carries the lowest risk of being used for money laundering, with the most common money laundering method being the banks.<ref>{{cite web |title=UK national risk assessment of money laundering and terrorist financing |url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/468210/UK_NRA_October_2015_final_web.pdf |publisher=UK HM Treasury and Home Office |accessdate=3 May 2016}}</ref> | |||
=== Ponzi scheme === | |||
In a ] that utilized bitcoins, The Bitcoin Savings and Trust promised investors up to 7 percent weekly interest, and raised at least 700,000 bitcoins from 2011 to 2012.<ref name=secponzi /> In July 2013 the U.S. Securities and Exchange Commission charged the company and its founder in 2013 "with defrauding investors in a Ponzi scheme involving bitcoin".<ref name=secponzi>{{cite press release |url=https://www.sec.gov/News/PressRelease/Detail/PressRelease/1370539730583 |date=23 July 2013 |issue=2013-132 |title=SEC charges Texas man with running Bitcoin-denominated Ponzi scheme |publisher=US Securities and Exchange Commission |accessdate=7 March 2014}}</ref> In September 2014 the judge fined Bitcoin Savings & Trust and its owner $40 million for operating a bitcoin Ponzi scheme.<ref>{{cite news |title=Bitcoin Savings & Trust Comes Up $40 Million Short On The Trust Part |url=http://www.forbes.com/sites/jayadkisson/2014/09/25/bitcoin-savings-trust-comes-up-40-million-short-on-the-trust-part/ |author=Jay Adkisson |date=25 September 2014 |accessdate=13 December 2014 |work=Personal Finance |publisher=Forbes}}</ref> | |||
=== Malware === | |||
==== Malware stealing ==== | |||
Some malware can steal private keys for bitcoin wallets allowing the bitcoins themselves to be stolen. The most common type searches computers for cryptocurrency wallets to upload to a remote server where they can be cracked and their coins stolen.<ref name=haj2014>{{cite news |url=http://www.coindesk.com/nearly-150-strains-malware-bitcoins/ |title=Nearly 150 strains of malware are after your bitcoins |first=Nermin |last=Hajdarbegovic |date=27 February 2014 |work=CoinDesk |accessdate=7 March 2014}}</ref> Many of these also ] to record passwords, often avoiding the need to crack the keys.<ref name=haj2014 /> A different approach detects when a bitcoin address is copied to a ] and quickly replaces it with a different address, tricking people into sending bitcoins to the wrong address.<ref>{{cite web |author1=Gregg Keizer |title=Bitcoin malware count soars as cryptocurrency value climbs |url=http://www.computerworld.com/article/2488144/malware-vulnerabilities/bitcoin-malware-count-soars-as-cryptocurrency-value-climbs.html |website=Computerworld |accessdate=8 January 2015 |date=28 February 2014}}</ref> This method is effective because bitcoin transactions are irreversible.<ref>{{cite book|last1=Barski|first1=Conrad|last2=Wilmer|first2=Chris|title=Bitcoin for the Befuddled|date=14 November 2014|publisher=No Starch Press|isbn=978-1-59327-573-0|accessdate=18 October 2016}}</ref>{{rp|57}} | |||
One ], spread through the Pony ], was reported in February 2014 to have stolen up to $220,000 in cryptocurrencies including bitcoins from 85 wallets.<ref>{{cite news |author1=Zach Miners |title=Bitcoins, other digital currencies stolen in massive 'Pony' botnet attack |url=http://www.pcworld.com/article/2101260/bitcoins-other-digital-currencies-stolen-in-massive-pony-botnet-attack.html |accessdate=8 January 2015 |date=24 February 2014}}</ref> Security company ], which tracked the malware, reports that its latest version was able to steal 30 types of digital currency.<ref>{{cite news |url=http://www.reuters.com/article/2014/02/24/us-bitcoin-security-idUSBREA1N1JO20140224 |title='Pony' botnet steals bitcoins, digital currencies: Trustwave |first=Jim |last=Finkle |date=24 February 2014 |work=Reuters |accessdate=7 March 2014}}</ref> | |||
A type of Mac malware active in August 2013, Bitvanity posed as a vanity wallet address generator and stole addresses and private keys from other bitcoin client software.<ref name=southurst2014>{{cite news |title=Watch out! Mac malware spread disguised as cracked versions of Angry Birds, Pixelmator and other top apps |url=http://www.eset.com/int/about/press/articles/article/watch-out-mac-malware-spread-disguised-as-cracked-versions-of-angry-birds-pixelmator-and-other-top-apps/ |accessdate=20 November 2015 |date=26 February 2014 |publisher=]}}</ref> A different trojan for Mac OS X, called CoinThief was reported in February 2014 to be responsible for multiple bitcoin thefts.<ref name=southurst2014 /> The software was hidden in versions of some cryptocurrency apps on ] and ].<ref name=southurst2014 /> | |||
==== Unauthorized mining ==== | |||
In June 2011, ] warned about the possibility that ]s could mine covertly for bitcoins.<ref>{{cite web |author=Peter Coogan |url=http://www.symantec.com/connect/blogs/bitcoin-botnet-mining |title=Bitcoin Botnet Mining |work=Symantec.com |date=17 June 2011 |accessdate=24 January 2012 |deadurl=no}}</ref> Malware used the ] capabilities of ]s built into many modern ]s.<ref>{{cite news |url=http://www.theregister.co.uk/2011/08/16/gpu_bitcoin_brute_forcing/ |title=Malware mints virtual currency using victim's GPU |work=The Register |date=16 August 2011 |accessdate=31 October 2014 |author=Goodin, Dan}}</ref> Although the average PC with an integrated graphics processor is virtually useless for bitcoin mining, tens of thousands of PCs laden with mining malware could produce some results.<ref name=tomsmining>{{cite web |last1=Ryder |first1=Greg |title=All About Bitcoin Mining: Road To Riches Or Fool's Gold? |url=http://www.tomshardware.com/reviews/bitcoin-mining-make-money,3514.html |publisher=Tom's hardware |date=9 June 2013 |accessdate=18 September 2015}}</ref> | |||
In mid-August 2011, bitcoin mining botnets were detected,<ref>{{cite web |url=http://www.infosecurity-magazine.com/view/20211/researcher-discovers-distributed-bitcoin-cracking-trojan-malware/ |title=Infosecurity - Researcher discovers distributed bitcoin cracking trojan malware |publisher=Infosecurity-magazine.com |date=19 August 2011 |accessdate=24 January 2012}}</ref> and less than three months later, bitcoin mining ] had infected ].<ref>{{cite web |url=http://www.techworld.com.au/article/405849/mac_os_x_trojan_steals_processing_power_produce_bitcoins |title=Mac OS X Trojan steals processing power to produce Bitcoins: Security researchers warn that DevilRobber malware could slow down infected Mac computers |author=Lucian Constantin |publisher=IDG communications |work=TechWorld |date=1 November 2011 |accessdate=24 January 2012}}</ref> | |||
In April 2013, ] organization E-Sports Entertainment was accused of hijacking 14,000 computers to mine bitcoins; the company later settled the case with the State of New Jersey.<ref>{{cite news |url=http://www.bbc.co.uk/news/technology-25014477 |title=E-Sports Entertainment settles Bitcoin botnet allegations |date=20 November 2013 |accessdate=24 November 2013 |work=]}}</ref> | |||
German police arrested two people in December 2013 who customized existing botnet software to perform bitcoin mining, which police said had been used to mine at least $950,000 worth of bitcoins.<ref>{{cite news |author1=Mohit Kumar |title=The Hacker News The Hacker News +1,440,833 ThAlleged Skynet Botnet creator arrested in Germany |url=http://thehackernews.com/2013/12/alleged-skynet-botnet-creator-arrested.html |accessdate=8 January 2015 |date=9 December 2013}}</ref> | |||
For four days in December 2013 and January 2014, ] Europe hosted an ad containing bitcoin mining malware that infected an estimated two million computers.<ref>{{cite news |first=Shane |last=McGlaun |title=Yahoo malware turned Euro PCs into bitcoin miners |url=http://www.slashgear.com/yahoo-malware-turned-euro-pcs-into-bitcoin-miners-09312529/ |accessdate=8 January 2015 |date=9 January 2014 |publisher=SlashGear}}</ref> The software, called ], was first detected in mid-2013 and has been bundled with many software packages. Microsoft has been removing the malware through its ] and other security software.<ref>{{cite news |author1=Liat Clark |title=Microsoft stopped Tor running automatically on botnet-infected systems |url=http://www.wired.co.uk/news/archive/2014-01/20/microsoft-removes-tor |accessdate=8 January 2015 |date=20 January 2014}}</ref> | |||
Several reports of employees or students using university or research computers to mine bitcoins have been published.<ref>{{cite news |last1=Hornyack |first1=Tim |title=US researcher banned for mining Bitcoin using university supercomputers |url=http://www.pcworld.com/article/2360840/us-researcher-banned-for-mining-bitcoin-using-university-supercomputers.html |accessdate=13 June 2014 |work=PC world.com |publisher=IDG Consumer & SMB |date=6 June 2014}}</ref> | |||
==== Ransomware ==== | |||
Another type of bitcoin-related malware is ]. One program called ], typically spread through legitimate-looking email attachments, encrypts the hard drive of an infected computer, then displays a countdown timer and demands a ransom, usually two bitcoins, to decrypt it.<ref name=guardian-ransomware>{{cite news |url=http://www.theguardian.com/technology/2014/feb/10/how-ransomware-turns-your-computer-bitcoin-miner-linkup |work=The Guardian |title=How Ransomware turns your computer into a bitcoin miner |date=10 February 2014 |accessdate=7 March 2014}}</ref> Massachusetts police said they paid a 2 bitcoin ransom in November 2013, worth more than $1,300 at the time, to decrypt one of their hard drives.<ref>{{cite news |url=http://www.theguardian.com/technology/2013/nov/21/us-police-force-pay-bitcoin-ransom-in-cryptolocker-malware-scam |title=US police force pay bitcoin ransom in Cryptolocker malware scam |work=The Guardian |first=Samuel |last=Gibbs |date=21 November 2013 |accessdate=7 March 2014}}</ref> Linkup, a combination ransomware and bitcoin mining program that surfaced in February 2014, disables internet access and demands credit card information to restore it, while secretly mining bitcoins.<ref name=guardian-ransomware /> | |||
== Security == | |||
Various potential attacks on the ] and its use as a payment system, real or theoretical, have been considered. The bitcoin protocol includes several features that protect it against some of those attacks, such as unauthorized spending, double spending, forging bitcoins, and tampering with the blockchain. Other attacks, such as theft of private keys, require due care by users.<ref name=quantitative /><ref name="primer" /><ref name="cornell4220" /><ref name="cr248" /><ref name="51%" /><ref name=reid /><ref name=dep2p /> | |||
=== Unauthorized spending === | |||
Unauthorized spending is mitigated by bitcoin's implementation of public-private key cryptography. For example; when Alice sends a bitcoin to Bob, Bob becomes the new owner of the bitcoin. Eve observing the transaction might want to spend the bitcoin Bob just received, but she cannot sign the transaction without the knowledge of Bob's private key.<ref name="primer" /> | |||
=== Double spending === | |||
A specific problem that an internet payment system must solve is ], whereby a user pays the same coin to two or more different recipients. An example of such a problem would be if Eve sent a bitcoin to Alice and later sent the same bitcoin to Bob. The bitcoin network guards against double-spending by recording all bitcoin transfers in a ledger (the blockchain) that is visible to all users, and ensuring for all transferred bitcoins that they haven't been previously spent.<ref name="primer" />{{rp|4}} | |||
=== Race attack === | |||
If Eve offers to pay Alice a bitcoin in exchange for goods and signs a corresponding transaction, it is still possible that she also creates a different transaction at the same time sending the same bitcoin to Bob. By the rules, the network accepts only one of the transactions. This is called a ], since there is a race which transaction will be accepted first. Alice can reduce the risk of race attack stipulating that she will not deliver the goods until Eve's payment to Alice appears in the blockchain.<ref name="cornell4220">{{cite web |url=http://blogs.cornell.edu/info4220/2013/03/29/bitcoin-and-the-double-spending-problem/ |title=Bitcoin and the Double-spending Problem |publisher=Cornell University |date=29 March 2013 |accessdate=22 October 2014 |author=Erik Bonadonna}}</ref> | |||
A variant race attack (which has been called a Finney attack by reference to Hal Finney) requires the participation of a miner. Instead of sending both payment requests (to pay Bob and Alice with the same coins) to the network, Eve issues only Alice's payment request to the network, while the accomplice tries to mine a block that includes the payment to Bob instead of Alice. There is a positive probability that the rogue miner will succeed before the network, in which case the payment to Alice will be rejected. As with the plain race attack, Alice can reduce the risk of a Finney attack by waiting for the payment to be included in the blockchain.<ref name="cr248">{{cite journal |title=Two Bitcoins at the Price of One? Double-Spending Attacks on Fast Payments in Bitcoin |url=http://eprint.iacr.org/2012/248.pdf |last1=Karame |first1=Ghassan O. |last2=Androulaki |first2=Elli |last3=Capkun |first3=Srdjan |publisher=International Association for Cryptologic Research |year=2012 |accessdate=22 October 2014}}</ref> | |||
=== History modification === | |||
Each block that is added to the blockchain, starting with the block containing a given transaction, is called a confirmation of that transaction. Ideally, merchants and services that receive payment in bitcoin should wait for at least one confirmation to be distributed over the network, before assuming that the payment was done. The more confirmations that the merchant waits for, the more difficult it is for an attacker to successfully reverse the transaction in a blockchain—unless the attacker controls more than half the total network power, in which case it is called a 51% attack.<ref name="51%">{{cite news |author1=Michael J. Casey |author2=Paul Vigna |title=Short-Term Fixes To Avert "51% Attack" |url=http://blogs.wsj.com/moneybeat/2014/06/16/bitbeat-a-51-attack-what-is-it-and-could-it-happen/ |accessdate=30 June 2014 |work=Money Beat |publisher=Wall Street Journal |date=16 June 2014}}</ref> | |||
=== Deanonymisation of clients === | |||
] is a strategy in data mining in which anonymous data is cross-referenced with other sources of data to re-identify the anonymous data source. Along with transaction graph analysis, which may reveal connections between bitcoin addresses (pseudonyms),<ref name=quantitative /><ref name=reid>{{cite journal |last1=Reid |first1=Fergal |last2=Harrigan |first2=Martin |title=An Analysis of Anonymity in the Bitcoin System |journal=Security and Privacy in Social Networks |date=2013 |pages=197–223}}</ref> there is a possible attack<ref name=dep2p>{{cite journal |last1=Biryukov |first1=Alex |last2=Khovratovich |first2=Dmitry |last3=Pustogarov |first3=Ivan |title=Deanonymisation of clients in Bitcoin P2P network |journal=ACM Conference on Computer and Communications Security |date=2014 |url=http://orbilu.uni.lu/handle/10993/18679}}</ref> which links a user's pseudonym to its ]. If the peer is using ], the attack includes a method to separate the peer from the Tor network, forcing them to use their real IP address for any further transactions. The attack makes use of bitcoin mechanisms of relaying peer addresses and anti-] protection. The cost of the attack on the full bitcoin network is under €1500 per month.<ref name="dep2p" /> | |||
== Data in the blockchain == | |||
While it is possible to store any digital file in the blockchain, the larger the transaction size, the larger any associated fees become.<ref name="bitcoinfees">{{cite web |title=How much will the transaction fee be? |url=http://bitcoinfees.com/ |publisher=Bitcoinfees.com |accessdate=30 November 2014}}</ref> Various items have been embedded, including URLs to child pornography, an ] image of ], material from the ], prayers from bitcoin miners, and the original bitcoin whitepaper.<ref name=BlockSpam>{{cite news |title=How porn links and Ben Bernanke snuck into Bitcoin's code |url=http://money.cnn.com/2013/05/02/technology/security/bitcoin-porn/ |website=CNN Money |publisher=CNN |date=2 May 2013}}</ref> | |||
== In academia == | |||
In the fall of 2014, undergraduate students at the ] (MIT) each received bitcoins worth $100 "to better understand this emerging technology". The bitcoins were not provided by MIT but rather the MIT Bitcoin Club, a student-run club.<ref name=MIT>{{cite news |last=Hern |first=Alex |title=MIT students to get $100 worth of bitcoin from Wall Street donor |url=http://www.theguardian.com/technology/2014/apr/29/mit-student-bitcoin-wall-street-donor |accessdate=1 May 2014 |newspaper=The Guardian |date=30 April 2014}}</ref><ref>{{cite web |url=http://bitcoin.mit.edu/announcing-the-mit-bitcoin-project/ |title=Announcing the MIT Bitcoin Project |publisher=MIT Bitcoin Club |date=29 April 2014 |accessdate=4 July 2015 |author=Dan}}</ref> | |||
== In art, entertainment, and media == | |||
=== Films === | |||
A documentary film called ''The Rise and Rise of Bitcoin'' (late 2014) features interviews with people who use bitcoin, such as a computer programmer and a drug dealer.<ref>{{cite news |url=http://www.nytimes.com/2014/10/03/movies/the-rise-and-rise-of-bitcoin-from-nicholas-mross.html?_r=0 |title=Financial Wild West |publisher=New York Times |work=nytimes.com |date=2 October 2014 |accessdate=8 May 2015 |author=Kenigsberg, Ben}}</ref> | |||
=== Music === | |||
Several lighthearted songs celebrating bitcoin have been released.<ref>{{cite news |url=http://blogs.wsj.com/moneybeat/2014/02/18/bitbeat-mt-goxs-pyrrhic-victory/ |title=BitBeat: Mt. Gox's Pyrrhic Victory |publisher=The Wall Street Journal |work=Money Beat |quote='Ode to Satoshi' is a bluegrass-style song with an old-timey feel that mixes references to Satoshi Nakamoto and blockchains (and, ahem, 'the fall of old Mt. Gox') with mandolin-picking and harmonicas. |date=18 February 2014 |accessdate=30 September 2014 |author=Paul Vigna}}</ref> | |||
=== Literature === | |||
In ]' science fiction novel '']'' (2014), a modification of bitcoin is used as the universal ] payment system. The functioning of the system is a major plot element of the book.<ref>''...very exchange between two beacons must be cryptographically signed by a third party bank in another star system: it take years to settle a transaction. It's theft-proof too – for each bitcoin is cryptographically signed by the mind of its owner''. Charles Stross. Neptune's Brood (Kindle edition). Ace, 2013, p. 109 (; )</ref> | |||
=== Television === | |||
In early 2015, the CNN series '']'' featured an episode about bitcoin. Filmed in July 2014, it featured Morgan Spurlock living off of bitcoins for a week to figure out whether the world is ready for a new kind of money.<ref>{{cite news |author1=Jason Kurtz |title=Buying bitcoin: Morgan Spurlock looks to live off online currency |url=http://www.cnn.com/2015/02/18/us/bitcoin-morgan-spurlock-inside-man/ |publisher=CNN |accessdate=25 February 2015 |date=20 February 2015}}</ref> | |||
== See also == | |||
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==Further reading== | ||
*{{cite web|last=Nakamoto|first=Satoshi|date=31 October 2008|title=Bitcoin: A Peer-to-Peer Electronic Cash System|url=https://bitcoin.org/bitcoin.pdf|url-status=dead|archive-url=https://web.archive.org/web/20140320135003/https://bitcoin.org/bitcoin.pdf|archive-date=20 March 2014|access-date=28 April 2014|publisher=bitcoin.org}} | |||
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== References == | |||
{{Reflist|25em|refs= | |||
<ref name="Antonopoulos2014">{{cite book |author=Andreas M. Antonopoulos |date=April 2014 |isbn=978-1-4493-7404-4 |publisher=O'Reilly Media |title=Mastering Bitcoin. Unlocking Digital Crypto-Currencies}}</ref> | |||
<ref name=kopstein>{{cite news |author1=Joshua Kopstein |title=The Mission to Decentralize the Internet |url=http://www.newyorker.com/tech/elements/the-mission-to-decentralize-the-internet |accessdate=30 December 2014 |publisher=The New Yorker |date=12 December 2013 |quote=The network's "nodes"—users running the bitcoin software on their computers—collectively check the integrity of other nodes to ensure that no one spends the same coins twice. All transactions are published on a shared public ledger, called the "blockchain"}}</ref> | |||
<ref name=btox>{{cite web |title=bitcoin |url=http://www.oxforddictionaries.com/definition/english/bitcoin |publisher=Oxford University Press |accessdate=28 December 2014}}</ref> | |||
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{{Bitcoin}} | {{Bitcoin}} | ||
{{Cryptocurrencies}} | {{Cryptocurrencies}} | ||
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{{Authority control}} | {{Authority control}} | ||
{{Subject bar|commons=Bitcoin|portal1=Business and economics|portal2=Free and open-source software|portal3=Internet|portal4=Numismatics|portal5=Money}} | |||
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Latest revision as of 18:50, 19 January 2025
Decentralized digital currency For the colloquial expression for coinage, see Bit (money). "₿" redirects here. Not to be confused with "฿" for Thai baht.
[REDACTED] Official logo from bitcoin.org | |
Denominations | |
---|---|
Plural | Bitcoins |
Symbol | ₿ (Unicode: U+20BF ₿ BITCOIN SIGN) |
Code | BTC |
Precision | 10 |
Subunits | |
1⁄1000 | Millibitcoin |
1⁄1000000 | Microbitcoin |
1⁄100000000 | Satoshi |
Development | |
Original author(s) | Satoshi Nakamoto |
White paper | "Bitcoin: A Peer-to-Peer Electronic Cash System" |
Implementation(s) | Bitcoin Core |
Initial release | 0.1.0 / 9 January 2009 (16 years ago) (2009-01-09) |
Latest release | 28.0 / 4 October 2024 (3 months ago) (2024-10-04) |
Code repository | github |
Development status | Active |
Written in | C++ |
Source model | Free and open-source software |
License | MIT License |
Ledger | |
Ledger start | 3 January 2009 (16 years ago) (2009-01-03) |
Timestamping scheme | Proof of work (partial hash inversion) |
Hash function | SHA-256 (two rounds) |
Issuance schedule | Decentralized (block reward) Initially ₿50 per block, halved every 210,000 blocks |
Block reward | ₿3.125 (as of 2024) |
Block time | 10 minutes |
Circulating supply | ₿19,591,231 (as of 6 January 2024) |
Supply limit | ₿21,000,000 |
Valuation | |
Exchange rate | Floating |
Demographics | |
Official user(s) | El Salvador |
Website | |
Website | bitcoin |
Bitcoin (abbreviation: BTC; sign: ₿) is the first decentralized cryptocurrency. Based on a free-market ideology, bitcoin was invented in 2008 by Satoshi Nakamoto, an unknown person. Use of bitcoin as a currency began in 2009, with the release of its open-source implementation. In 2021, El Salvador adopted it as legal tender. It is mostly seen as an investment and has been described by some scholars as an economic bubble. As bitcoin is pseudonymous, its use by criminals has attracted the attention of regulators, leading to its ban by several countries as of 2021.
Nodes in the peer-to-peer bitcoin network verify transactions through cryptography and record them in a public distributed ledger, called a blockchain, without central oversight. Consensus between nodes is achieved using a computationally intensive process based on proof of work, called mining, that secures the bitcoin blockchain. Mining consumes large quantities of electricity and has been criticized for its environmental impact.
History
Main article: History of bitcoinBackground
Before bitcoin, several digital cash technologies were released, starting with David Chaum's ecash in the 1980s. The idea that solutions to computational puzzles could have some value was first proposed by cryptographers Cynthia Dwork and Moni Naor in 1992. The concept was independently rediscovered by Adam Back who developed Hashcash, a proof-of-work scheme for spam control in 1997. The first proposals for distributed digital scarcity-based cryptocurrencies came from cypherpunks Wei Dai (b-money) and Nick Szabo (bit gold) in 1998. In 2004, Hal Finney developed the first currency based on reusable proof of work. These various attempts were not successful: Chaum's concept required centralized control and no banks wanted to sign on, Hashcash had no protection against double-spending, while b-money and bit gold were not resistant to Sybil attacks.
2008–2009: Creation
External image | |
---|---|
Cover page of The Times 3 January 2009 showing the headline used in the genesis block |
The domain name bitcoin.org was registered on 18 August 2008. On 31 October 2008, a link to a white paper authored by Satoshi Nakamoto titled Bitcoin: A Peer-to-Peer Electronic Cash System was posted to a cryptography mailing list. Nakamoto implemented the bitcoin software as open-source code and released it in January 2009. Nakamoto's identity remains unknown. According to computer scientist Arvind Narayanan, all individual components of bitcoin originated in earlier academic literature. Nakamoto's innovation was their complex interplay resulting in the first decentralized, Sybil resistant, Byzantine fault tolerant digital cash system, that would eventually be referred to as the first blockchain. Nakamoto's paper was not peer reviewed and was initially ignored by academics, who argued that it could not work.
On 3 January 2009, the bitcoin network was created when Nakamoto mined the starting block of the chain, known as the genesis block. Embedded in this block was the text "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks", which is the date and headline of an issue of The Times newspaper. Nine days later, Hal Finney received the first bitcoin transaction: ten bitcoins from Nakamoto. Wei Dai and Nick Szabo were also early supporters. On May 22, 2010, the first known commercial transaction using bitcoin occurred when programmer Laszlo Hanyecz bought two Papa John's pizzas for ₿10,000, in what would later be celebrated as "Bitcoin Pizza Day".
2010–2012: Early growth
Blockchain analysts estimate that Nakamoto had mined about one million bitcoins before disappearing in 2010 when he handed the network alert key and control of the code repository over to Gavin Andresen. Andresen later became lead developer at the Bitcoin Foundation, an organization founded in September 2012 to promote bitcoin.
After early "proof-of-concept" transactions, the first major users of bitcoin were black markets, such as the dark web Silk Road. During its 30 months of existence, beginning in February 2011, Silk Road exclusively accepted bitcoins as payment, transacting ₿9.9 million, worth about $214 million.
2013–2014: First regulatory actions
In March 2013, the US Financial Crimes Enforcement Network (FinCEN) established regulatory guidelines for "decentralized virtual currencies" such as bitcoin, classifying American bitcoin miners who sell their generated bitcoins as money services businesses, subject to registration and other legal obligations. In May 2013, US authorities seized the unregistered exchange Mt. Gox. In June 2013, the US Drug Enforcement Administration seized ₿11.02 from an individual attempting to use them to purchase illicit drugs. This marked the first time a government agency had seized bitcoins. The FBI seized about ₿30,000 in October 2013 from Silk Road, following the arrest of its founder Ross Ulbricht.
In December 2013, the People's Bank of China prohibited Chinese financial institutions from using bitcoin. After the announcement, the value of bitcoin dropped, and Baidu no longer accepted bitcoins for certain services. Buying real-world goods with any virtual currency had been illegal in China since at least 2009.
2015–2019
Research produced by the University of Cambridge estimated that in 2017, there were 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using bitcoin. In August 2017, the SegWit software upgrade was activated. Segwit was intended to support the Lightning Network as well as improve scalability. SegWit opponents, who supported larger blocks as a scalability solution, forked to create Bitcoin Cash, one of many forks of bitcoin.
In December 2017, the first futures on bitcoin was introduced by the Chicago Mercantile Exchange (CME).
In February 2018, the price crashed after China imposed a complete ban on bitcoin trading. The percentage of bitcoin trading in the Chinese renminbi fell from over 90% in September 2017 to less than 1% in June 2018. During the same year, bitcoin prices were negatively affected by several hacks or thefts from cryptocurrency exchanges.
2020–present
In 2020, some major companies and institutions started to acquire bitcoin: MicroStrategy invested $250 million in bitcoin as a treasury reserve asset, Square, Inc., $50 million, and MassMutual, $100 million. In November 2020, PayPal added support for bitcoin in the US.
In February 2021, bitcoin's market capitalization reached $1 trillion for the first time. In November 2021, the Taproot soft-fork upgrade was activated, adding support for Schnorr signatures, improved functionality of smart contracts and Lightning Network. Before, bitcoin only used a custom elliptic curve with the ECDSA algorithm to produce signatures. In September 2021, bitcoin became legal tender in El Salvador, alongside the US dollar. In October 2021, the first bitcoin futures exchange-traded fund (ETF), called BITO, from ProShares was approved by the SEC and listed on the CME.
In early 2022, during the Canadian trucker protests opposing COVID-19 vaccine mandates, organizers turned to bitcoin to receive donations after traditional financial platforms restricted access to funding. Proponents highlighted bitcoin's use as a tool for fundraising in situations where access to conventional financial systems may be restricted. In May and June 2022, the bitcoin price fell following the collapses of TerraUSD, a stablecoin, and the Celsius Network, a cryptocurrency loan company.
In 2023, ordinals—non-fungible tokens (NFTs)—on bitcoin, went live. As of June 2023, River Financial estimated that bitcoin had 81.7 million users, about 1% of the global population. In January 2024, the first 11 US spot bitcoin ETFs began trading, offering direct exposure to bitcoin for the first time on American stock exchanges. In December 2024, bitcoin price reached $100,000 for the first time, as US president-elect Donald Trump promised to make the US the "crypto capital of the planet" and to stockpile bitcoin. The same month, BlackRock, the world's largest asset manager, recommended investors to allocate up to 2% of their portfolio to bitcoin.
Design
Main article: Bitcoin protocolUnits and divisibility
The unit of account of the bitcoin system is the bitcoin. It is most commonly represented with the symbol ₿ and the currency code BTC. However, the BTC code does not conform to ISO 4217 as BT is the country code of Bhutan, and ISO 4217 requires the first letter used in global commodities to be 'X'. XBT, a code that conforms to ISO 4217 though not officially part of it, is used by Bloomberg L.P.
No uniform capitalization convention exists; some sources use Bitcoin, capitalized, to refer to the technology and network, and bitcoin, lowercase, for the unit of account. The Cambridge Advanced Learner's Dictionary and the Oxford Advanced Learner's Dictionary use the capitalized and lowercase variants without distinction.
One bitcoin is divisible to eight decimal places. Units for smaller amounts of bitcoin are the millibitcoin (mBTC), equal to 1⁄1000 bitcoin, and the satoshi (sat), representing 1⁄100000000 (one hundred millionth) bitcoin, the smallest amount possible. 100,000 satoshis are one mBTC.
Blockchain
Further information: Blockchain § Structure and designAs a decentralized system, bitcoin operates without a central authority or single administrator, so that anyone can create a new bitcoin address and transact without needing any approval. This is accomplished through a specialized distributed ledger called a blockchain that records bitcoin transactions.
The blockchain is implemented as an ordered list of blocks. Each block contains a SHA-256 hash of the previous block, chaining them in chronological order. The blockchain is maintained by a peer-to-peer network. Individual blocks, public addresses, and transactions within blocks are public information, and can be examined using a blockchain explorer.
Nodes validate and broadcast transactions, each maintaining a copy of the blockchain for ownership verification. A new block is created every 10 minutes on average, updating the blockchain across all nodes without central oversight. This process tracks bitcoin spending, ensuring each bitcoin is spent only once. Unlike a traditional ledger that tracks physical currency, bitcoins exist digitally as unspent outputs of transactions.
Addresses and transactions
In the blockchain, bitcoins are linked to specific addresses that are hashes of a public key. Creating an address involves generating a random private key and then computing the corresponding address. This process is almost instant, but the reverse (finding the private key for a given address) is nearly impossible. Publishing a bitcoin address does not risk its private key, and it is extremely unlikely to accidentally generate a used key with funds. To use bitcoins, owners need their private key to digitally sign transactions, which are verified by the network using the public key, keeping the private key secret.
Bitcoin transactions use a Forth-like scripting language, involving one or more inputs and outputs. When sending bitcoins, a user specifies the recipients' addresses and the amount for each output. This allows sending bitcoins to several recipients in a single transaction. To prevent double-spending, each input must refer to a previous unspent output in the blockchain. Using multiple inputs is similar to using multiple coins in a cash transaction. As in a cash transaction, the sum of inputs can exceed the intended sum of payments. In such a case, an additional output can return the change back to the payer. Unallocated input satoshis in the transaction become the transaction fee.
Losing a private key means losing access to the bitcoins, with no other proof of ownership accepted by the protocol. For instance, in 2013, a user lost ₿7,500, valued at US$7.5 million, by accidentally discarding a hard drive with the private key. It is estimated that around 20% of all bitcoins are lost. The private key must also be kept secret as its exposure, such as through a data breach, can lead to theft of the associated bitcoins. As of December 2017, approximately ₿980,000 had been stolen from cryptocurrency exchanges.
Mining
See also: Bitcoin protocol § MiningThe mining process in bitcoin involves maintaining the blockchain through computer processing power. Miners group and broadcast new transactions into blocks, which are then verified by the network. Each block must contain a proof of work (PoW) to be accepted, involving finding a nonce number that, combined with the block content, produces a hash numerically smaller than the network's difficulty target. This PoW is simple to verify but hard to generate, requiring many attempts. PoW forms the basis of bitcoin's consensus mechanism.
The difficulty of generating a block is deterministically adjusted based on the mining power on the network by changing the difficulty target, which is recalibrated every 2,016 blocks (approximately two weeks) to maintain an average time of ten minutes between new blocks. The process requires significant computational power and specialized hardware.
Miners who successfully find a new block can collect transaction fees from the included transactions and a set reward in bitcoins. To claim this reward, a special transaction called a coinbase is included in the block, with the miner as the payee. All bitcoins in existence have been created through this type of transaction. This reward is halved every 210,000 blocks until ₿21 million, with new bitcoin issuance slated to end around 2140. Afterward, miners will only earn from transaction fees. These fees are determined by the transaction's size and the amount of data stored, measured in satoshis per byte.
The proof of work system and the chaining of blocks make blockchain modifications very difficult, as altering one block requires changing all subsequent blocks. As more blocks are added, modifying older blocks becomes increasingly challenging. In case of disagreement, nodes trust the longest chain, which required the greatest amount of effort to produce. To tamper or censor the ledger, one needs to control the majority of the global hashrate. The high cost required to reach this level of computational power secures the bitcoin blockchain.
Bitcoin mining's environmental impact is controversial and has attracted the attention of regulators, leading to restrictions or incentives in various jurisdictions. As of 2022, a non-peer-reviewed study by the Cambridge Centre for Alternative Finance (CCAF) estimated that bitcoin mining represented 0.4% of global electricity consumption. Another 2022 non-peer-reviewed commentary published in Joule estimated that bitcoin mining was responsible for 0.2% of world greenhouse gas emissions. About half of the electricity used is generated through fossil fuels. Moreover, mining hardware's short lifespan results in electronic waste. The amount of electrical energy consumed, and the e-waste generated, is comparable to that of Greece and the Netherlands, respectively.
Privacy and fungibility
Bitcoin is pseudonymous, with funds linked to addresses, not real-world identities. While the owners of these addresses are not directly identified, all transactions are public on the blockchain. Patterns of use, like spending coins from multiple inputs, can hint at a common owner. Public data can sometimes be matched with known address owners. Bitcoin exchanges might also need to collect personal data as per legal requirements. For enhanced privacy, users can generate a new address for each transaction.
In the bitcoin network, each bitcoin is treated equally, ensuring basic fungibility. However, users and applications can choose to differentiate between bitcoins. While wallets and software treat all bitcoins the same, each bitcoin's transaction history is recorded on the blockchain. This public record allows for chain analysis, where users can identify and potentially reject bitcoins from controversial sources. For example, in 2012, Mt. Gox froze accounts containing bitcoins identified as stolen.
Wallets
For broader coverage of this topic, see Cryptocurrency wallet. Screenshot of Bitcoin CoreA paper wallet with the address as a QR code while the private key is hiddenA hardware wallet which processes bitcoin transactions without exposing private keysBitcoin wallets were the first cryptocurrency wallets, enabling users to store the information necessary to transact bitcoins. The first wallet program, simply named Bitcoin, and sometimes referred to as the Satoshi client, was released in 2009 by Nakamoto as open-source software. Bitcoin Core is among the best known clients. Forks of Bitcoin Core exist such as Bitcoin Unlimited. Wallets can be full clients, with a full copy of the blockchain to check the validity of mined blocks, or lightweight clients, just to send and receive transactions without a local copy of the entire blockchain. Third-party internet services, called online wallets or hot wallets, store users' credentials on their servers, making them susceptible of hacks. Cold storage protects bitcoins from such hacks by keeping private keys offline, either through specialized hardware wallets or paper printouts.
Scalability and decentralization challenges
Nakamoto limited the block size to one megabyte. The limited block size and frequency can lead to delayed processing of transactions, increased fees and a bitcoin scalability problem. The Lightning Network, second-layer routing network, is a potential scaling solution.
Research shows a trend towards centralization in bitcoin as miners join pools for stable income. If a single miner or pool controls more than 50% of the hashing power, it would allow them to censor transactions and double-spend coins. In 2014, mining pool Ghash.io reached 51% mining power, causing safety concerns, but later voluntarily capped its power at 39.99% for the benefit of the whole network. A few entities also dominate other parts of the ecosystem such as the client software, online wallets, and simplified payment verification (SPV) clients.
Economics and usage
Main article: Economics of bitcoinBitcoin's theoretical roots and ideology
According to the European Central Bank, the decentralization of money offered by bitcoin has its theoretical roots in the Austrian school of economics, especially with Friedrich Hayek's The Denationalisation of Money, in which he advocates a complete free market in the production, distribution and management of money to end the monopoly of central banks. Sociologist Nigel Dodd argues that the essence of the bitcoin ideology is to remove money from social, as well as governmental, control. The Economist describes bitcoin as "a techno-anarchist project to create an online version of cash, a way for people to transact without the possibility of interference from malicious governments or banks". These philosophical ideas initially attracted libertarians and anarchists. Economist Paul Krugman argues that cryptocurrencies like bitcoin are only used by bank skeptics and criminals.
Recognition as a currency and legal status
Money serves three purposes: a store of value, a medium of exchange, and a unit of account. According to The Economist in 2014, bitcoin functions best as a medium of exchange. In 2015, The Economist noted that bitcoins had three qualities useful in a currency: they are "hard to earn, limited in supply and easy to verify". However, a 2018 assessment by The Economist stated that cryptocurrencies met none of these three criteria. Per some researchers, as of 2015, bitcoin functions more as a payment system than as a currency. In 2014, economist Robert J. Shiller wrote that bitcoin has potential as a unit of account for measuring the relative value of goods, as with Chile's Unidad de Fomento, but that "Bitcoin in its present form... doesn't really solve any sensible economic problem". François R. Velde, Senior Economist at the Chicago Fed, described bitcoin as "an elegant solution to the problem of creating a digital currency". David Andolfatto, Vice President at the Federal Reserve Bank of St. Louis, stated that bitcoin is a threat to the establishment, which he argues is a good thing for the Federal Reserve System and other central banks, because it prompts these institutions to operate sound policies.
The legal status of bitcoin varies substantially from one jurisdiction to another. Because of its decentralized nature and its global presence, regulating bitcoin is difficult. However, the use of bitcoin can be criminalized, and shutting down exchanges and the peer-to-peer economy in a given country would constitute a de facto ban. The use of bitcoin by criminals has attracted the attention of financial regulators, legislative bodies, and law enforcement. Nobel-prize winning economist Joseph Stiglitz says that bitcoin's anonymity encourages money laundering and other crimes. This is the main justification behind bitcoin bans. As of November 2021, nine countries applied an absolute ban (Algeria, Bangladesh, China, Egypt, Iraq, Morocco, Nepal, Qatar, and Tunisia) while another 42 countries had an implicit ban. Bitcoin is only legal tender in El Salvador.
Use for payments
As of 2018, bitcoin is rarely used in transactions with merchants, but it is popular to purchase illegal goods online. Prices are not usually quoted in bitcoin and trades involve conversions into fiat currencies. Commonly cited reasons for not using bitcoin include high costs, the inability to process chargebacks, high price volatility, long transaction times, and transaction fees (especially for small purchases). Bloomberg reported that bitcoin was being used for large-item purchases on the site Overstock.com and for cross-border payments to freelancers. As of 2015, there was little sign of bitcoin use in international remittances despite high fees charged by banks and Western Union who compete in this market. Despite associated risks and costs, in 2022, a growing use of bitcoin, alongside cash and cards, was reported in restaurant business.
In September 2021, the Bitcoin Law made bitcoin legal tender in El Salvador, alongside the US dollar. The adoption has been criticized internationally and within El Salvador. In 2022, the International Monetary Fund (IMF) urged El Salvador to reverse its decision. As of 2022, the use of Bitcoin in El Salvador remains low: 80% of businesses refused to accept it. In April 2022, the Central African Republic (CAR) adopted bitcoin as legal tender alongside the CFA franc, but repealed the reform one year later.
Bitcoin is also used by some governments. For instance, the Iranian government initially opposed cryptocurrencies, but later saw them as an opportunity to circumvent sanctions. Since 2020, Iran has required local bitcoin miners to sell bitcoin to the Central Bank of Iran, allowing the central bank to use it for imports. Some constituent states also accept tax payments in bitcoin, including Colorado (US) and Zug (Switzerland). As of 2023, the US government owned more than $5 billion worth of seized bitcoin.
Use for investment and status as an economic bubble
Further information: Cryptocurrency bubbleAs of 2018, the overwhelming majority of bitcoin transactions took place on cryptocurrency exchanges. Since 2014, regulated bitcoin funds also allow exposure to the asset or to futures as an investment. Bitcoin is used as a store of value: individuals and companies such as the Winklevoss twins and Elon Musk's companies SpaceX and Tesla have massively invested in bitcoin. Bitcoin wealth is highly concentrated, with 0.01% holding 27% of in-circulation currency, as of 2021. As of September 2023, El Salvador had $76.5 million worth of bitcoin in its international reserves.
In 2018, research published in the Journal of Monetary Economics concluded that price manipulation occurred during the Mt. Gox bitcoin theft and that the market remained vulnerable to manipulation. Research published in The Journal of Finance also suggested that trading associated with increases in the amount of the Tether cryptocurrency and associated trading at the Bitfinex exchange accounted for about half of the price increase in bitcoin in late 2017.
Bitcoin, along with other cryptocurrencies, has been described as an economic bubble by several economists, including Nobel Prize in Economics laureates, such as Joseph Stiglitz, James Heckman, and Paul Krugman. Another recipient of the prize, Robert Shiller, argues that bitcoin is rather a fad that may become an asset class. He describes its price growth as an "epidemic", driven by contagious narratives. In 2024, Jean Tirole, also Nobel laureate, described bitcoin as a "pure bubble" as its intrinsic value is zero. According to him, some bubbles are long-lasting such as gold and fiat currencies, and it's impossible to predict whether bitcoin will collapse like other financial bubbles or become the new gold. The same year, Federal Reserve Chair Jerome Powell described bitcoin as a digital competitor to gold but not to the dollar as he argued it is a highly volatile speculative asset not used as a form of payment.
According to research published in the International Review of Financial Analysis in 2018, bitcoin as an asset is highly volatile and does not behave like any other conventional asset. According to one 2022 analysis published in The Journal of Alternative Investments, bitcoin was less volatile than oil, silver, US Treasuries, and 190 stocks in the S&P 500 during and after the 2020 stock market crash. The term hodl was created in December 2013 for holding bitcoin rather than selling it during periods of volatility.
Other economists, investors, and the central bank of Estonia have described bitcoin as a potential Ponzi scheme. Legal scholar Eric Posner disagrees, however, as "a real Ponzi scheme takes fraud; bitcoin, by contrast, seems more like a collective delusion". A 2014 World Bank report also concluded that bitcoin was not a deliberate Ponzi scheme.
See also
Notes
- ^ Named after Satoshi Nakamoto
- ^ The exact number is ₿20,999,999.9769.
References
- ^ "Unicode 10.0.0". Unicode Consortium. 20 June 2017. Archived from the original on 20 June 2017. Retrieved 20 June 2017.
- ^ Bradbury, Danny (November 2013). "The problem with Bitcoin". Computer Fraud & Security. 2013 (11): 5–8. doi:10.1016/S1361-3723(13)70101-5. ISSN 1361-3723. Archived from the original on 18 January 2023. Retrieved 25 November 2023.
- "Bitcoin Core 28.0 released". 2 October 2024. Archived from the original on 5 October 2024. Retrieved 5 October 2024.
- ^ "El Salvador's dangerous gamble on bitcoin". The editorial board. Financial Times. 7 September 2021. Archived from the original on 7 September 2021. Retrieved 7 September 2021.
- ^ S., L. (2 November 2015). "Who is Satoshi Nakamoto?". The Economist. Archived from the original on 22 November 2020. Retrieved 21 November 2023.
- ^ Davis, Joshua (10 October 2011). "The Crypto-Currency: Bitcoin and its mysterious inventor". The New Yorker. Archived from the original on 1 November 2014. Retrieved 31 October 2014.
- ^ Antonopoulos, Andreas M. (2014). Mastering Bitcoin: Unlocking Digital Crypto-Currencies. O'Reilly Media. ISBN 978-1-4493-7404-4.
- ^ Wolff-Mann, Ethan (27 April 2018). "'Only good for drug dealers': More Nobel prize winners snub bitcoin". Yahoo Finance. Archived from the original on 12 June 2018. Retrieved 7 June 2018.
- ^ Sun Yin, Hao Hua; Langenheldt, Klaus; Harlev, Mikkel; Mukkamala, Raghava Rao; Vatrapu, Ravi (2 January 2019). "Regulating Cryptocurrencies: A Supervised Machine Learning Approach to De-Anonymizing the Bitcoin Blockchain". Journal of Management Information Systems. 36 (1): 65. doi:10.1080/07421222.2018.1550550. ISSN 0742-1222. S2CID 132398387. Archived from the original on 21 April 2024. Retrieved 29 November 2023.
- Huang, Jon; O’Neill, Claire; Tabuchi, Hiroko (3 September 2021). "Bitcoin Uses More Electricity Than Many Countries. How Is That Possible?". The New York Times. ISSN 0362-4331. Archived from the original on 17 February 2023. Retrieved 26 October 2022.
- ^ Narayanan, Arvind; Clark, Jeremy (27 November 2017). "Bitcoin's academic pedigree". Communications of the ACM. 60 (12): 36–45. doi:10.1145/3132259. ISSN 0001-0782. S2CID 6425116. Archived from the original on 14 October 2023. Retrieved 22 November 2023.
- Dwork, Cynthia; Naor, Moni (1993), Brickell, Ernest F. (ed.), "Pricing via Processing or Combatting Junk Mail", Advances in Cryptology — CRYPTO’ 92, vol. 740, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 139–147, doi:10.1007/3-540-48071-4_10, ISBN 978-3-540-57340-1, retrieved 2 January 2025
- Tschorsch, Florian; Scheuermann, Bjorn (2 March 2016). "Bitcoin and Beyond: A Technical Survey on Decentralized Digital Currencies". IEEE Communications Surveys & Tutorials. 18 (3): 2084–2123. doi:10.1109/COMST.2016.2535718. ISSN 1553-877X. S2CID 5115101. Archived from the original on 19 November 2023. Retrieved 23 November 2023.
- Judmayer, Aljosha; Stifter, Nicholas; Krombholz, Katharina; Weippl, Edgar (2017). "History of Cryptographic Currencies". Blocks and Chains. Synthesis Lectures on Information Security, Privacy, and Trust. Springer. pp. 15–18. doi:10.1007/978-3-031-02352-1_3. ISBN 978-3-031-01224-2. Archived from the original on 22 November 2023. Retrieved 22 November 2023.
- Bernard, Zoë (2 December 2017). "Everything you need to know about Bitcoin, its mysterious origins, and the many alleged identities of its creator". Business Insider. Archived from the original on 15 June 2018. Retrieved 15 June 2018.
- Finley, Klint (31 October 2018). "After 10 Years, Bitcoin Has Changed Everything—And Nothing". Wired. Archived from the original on 5 November 2018. Retrieved 9 November 2018.
- Economist Staff (31 October 2015). "Blockchains: The great chain of being sure about things". The Economist. Archived from the original on 3 July 2016. Retrieved 18 June 2016.
- ^ Wallace, Benjamin (23 November 2011). "The Rise and Fall of Bitcoin". Wired. Archived from the original on 31 October 2013. Retrieved 13 October 2012.
- Popper, Nathaniel (30 August 2014). "Hal Finney, Cryptographer and Bitcoin Pioneer, Dies at 58". The New York Times. Archived from the original on 3 September 2014. Retrieved 2 September 2014.
- Cooper, Anderson (16 May 2019). "Meet the man who spent millions worth of bitcoin on pizza". CBS News. Archived from the original on 8 December 2021. Retrieved 8 December 2021.
- McMillan, Robert. "Who Owns the World's Biggest Bitcoin Wallet? The FBI". Wired. Archived from the original on 21 October 2016. Retrieved 7 October 2016.
- Simonite, Tom (15 August 2014). "Meet Gavin Andresen, the most powerful person in the world of Bitcoin". MIT Technology Review. Archived from the original on 22 November 2023. Retrieved 22 November 2023.
- Odell, Matt (21 September 2015). "A Solution To Bitcoin's Governance Problem". TechCrunch. Archived from the original on 26 January 2016. Retrieved 24 January 2016.
- Bustillos, Maria (1 April 2013). "The Bitcoin Boom". The New Yorker. Archived from the original on 2 July 2018. Retrieved 30 July 2018.
- ^ Rainer Böhme; Nicolas Christin; Benjamin Edelman; Tyler Moore (2015). "Bitcoin: Economics, Technology, and Governance". Journal of Economic Perspectives. 29 (2): 213–238. doi:10.1257/jep.29.2.213. ISSN 0895-3309.
- Lee, Timothy B. (19 March 2013). "US regulator Bitcoin Exchanges Must Comply With Money Laundering Laws". Ars Technica. Archived from the original on 21 October 2013. Retrieved 28 July 2017.
- Dillet, Romain. "Feds Seize Assets From Mt. Gox's Dwolla Account, Accuse It Of Violating Money Transfer Regulations". TechCrunch. Archived from the original on 9 October 2013. Retrieved 15 May 2013.
- Sampson, Tim (2013). "U.S. government makes its first-ever Bitcoin seizure". The Daily Dot. Archived from the original on 12 July 2013. Retrieved 15 October 2013.
- Hill, Kashmir. "The FBI's Plan For The Millions Worth Of Bitcoins Seized From Silk Road". Forbes. Archived from the original on 2 May 2014.
- Kelion, Leo (18 December 2013). "Bitcoin sinks after China restricts yuan exchanges". BBC News. Archived from the original on 19 December 2013. Retrieved 20 December 2013.
- "China bans banks from bitcoin transactions". The Sydney Morning Herald. Reuters. 6 December 2013. Archived from the original on 23 March 2014. Retrieved 31 October 2014.
- "Baidu Stops Accepting Bitcoins After China Ban". Bloomberg. New York. 7 December 2013. Archived from the original on 10 December 2013. Retrieved 11 December 2013.
- "China bars use of virtual money for trading in real goods". English.mofcom.gov.cn. 29 June 2009. Archived from the original on 29 November 2013. Retrieved 10 January 2014.
- Hileman, Garrick; Rauchs, Michel. "Global Cryptocurrency Benchmarking Study" (PDF). Cambridge University. Archived (PDF) from the original on 10 April 2017. Retrieved 14 April 2017.
- Vigna, Paul (21 July 2017). "Bitcoin Rallies Sharply After Vote Resolves Bitter Scaling Debate". The Wall Street Journal. Archived from the original on 21 November 2023. Retrieved 21 November 2023.
- Selena Larson (1 August 2017). "Bitcoin split in two, here's what that means". CNN Tech. Cable News Network. Archived from the original on 27 February 2018. Retrieved 2 April 2018.
- Cheng, Evelyn (17 December 2017). "Bitcoin debuts on the world's largest futures exchange, and prices fall slightly". CNBC. Archived from the original on 18 January 2024. Retrieved 19 January 2024.
- French, Sally (9 February 2017). "Here's proof that this bitcoin crash is far from the worst the cryptocurrency has seen". Market Watch. Archived from the original on 3 July 2018. Retrieved 3 July 2018.
- "RMB Bitcoin trading falls below 1 pct of world total". Xinhuanet. Xinhua. 7 July 2018. Archived from the original on 10 July 2018. Retrieved 10 July 2018.
- Chavez-Dreyfuss, Gertrude (3 July 2018). "Cryptocurrency exchange theft surges in first half of 2018: report". Reuters. Archived from the original on 4 July 2018. Retrieved 10 July 2018.
- "Coinbase Bitcoin". Coinbase. Federal Reserve Economic Data. 4 December 2024. Retrieved 4 December 2024.
- Cuthbertson, Anthony (13 September 2021). "MicroStrategy buys another $250m worth of bitcoin in hope of 100X price growth". The Independent. Archived from the original on 22 November 2023. Retrieved 22 November 2023.
- Oliver Effron. "Square just bought $50 million in bitcoin". CNN. Archived from the original on 24 October 2020. Retrieved 22 October 2020.
- Olga Kharif (11 December 2020). "169-Year-Old MassMutual Invests $100 Million in Bitcoin". Bloomberg. Archived from the original on 19 December 2020. Retrieved 26 December 2020.
- "PayPal says all users in US can now buy, hold and sell cryptocurrencies". Techcrunch. 13 November 2020. Archived from the original on 24 November 2020. Retrieved 26 November 2020.
- Chavez-Dreyfuss, Gertrude; Wilson, Tom (19 February 2021). "Bitcoin hits $1 trillion market cap, surges to fresh all-time peak". Reuters. Retrieved 24 November 2023.
- Sigalos, MacKenzie (14 November 2021). "Bitcoin's biggest upgrade in four years just happened – here's what changes". CNBC. Archived from the original on 14 November 2021. Retrieved 15 November 2021.
- Van Hijfte, Stijn (2020). Blockchain Platforms: A Look at the Underbelly of Distributed Platforms. Morgan & Claypool Publishers. ISBN 978-1681738925.
- Wursthorn, Michael (19 October 2021). "A Bitcoin ETF Is Here. What Does That Mean for Investors?". The Wall Street Journal. Archived from the original on 10 January 2024. Retrieved 11 January 2024.
- Loh, Matthew. "Canada says it will freeze the bank accounts of 'Freedom Convoy' truckers who continue their anti-vaccine mandate blockades". Business Insider. Retrieved 19 January 2025.
- "Crypto enthusiasts keep funding convoy protests as traditional banks take action against it - The Globe and Mail". The Globe and Mail. 8 December 2024. Retrieved 19 January 2025.
- "Meet Greg Foss: A Former Bitcoin Fundraiser For Canada's 'Freedom Convoy' Protest". Forbes. 20 June 2024. Retrieved 19 January 2025.
- "Elon Musk–backed 'freedom truckers' in Canada get Bitcoin lifeline after GoFundMe freezes millions in donations". Yahoo! Finance. 13 March 2022. Retrieved 19 January 2025.
- Browne, Ryan (10 May 2022). "Bitcoin investors are panicking as a controversial crypto experiment unravels". CNBC. Archived from the original on 11 May 2022. Retrieved 11 May 2022.
- Milmo, Dan (18 June 2022). "Bitcoin value slumps below $20,000 in cryptocurrencies turmoil". The Guardian. Archived from the original on 18 June 2022. Retrieved 19 June 2022.
- Yaffe-Bellany, David (13 June 2022). "Celsius Network Leads Crypto Markets Into Another Free Fall". The New York Times. Archived from the original on 14 June 2022. Retrieved 14 June 2022.
- Behrendt, Philipp (2023). "Taxation of the New Age: New Guidance for the World of Digital Assets". Journal of Tax Practice & Procedure. 25: 47. Archived from the original on 21 November 2023. Retrieved 21 November 2023.
- "As banks buy up bitcoins, who else are the 'Bitcoin whales'?". BBC Home. 1 March 2024. Retrieved 14 March 2024.
- Schmitt, Will (12 January 2024). "Bitcoin trading volumes surge after debut of long-awaited US ETFs". Financial Times. Archived from the original on 12 January 2024. Retrieved 12 January 2024.
- Lang, Hannah (11 January 2024). "US bitcoin ETFs see $4.6B in volume in first day of trading". Reuters. Retrieved 12 January 2024.
- "Bitcoin storms above $100,000 as Trump 2.0 fuels crypto euphoria". Reuters. 5 December 2024.
- McGee, Suzanne (12 December 2024). "BlackRock recommends bitcoin portfolio weighting of up to 2% for interested investors". Reuters.
- ^ Alexander, Carol; Imeraj, Arben (2019). "Introducing the BITIX: The Bitcoin Fear Gauge". SSRN Electronic Journal. doi:10.2139/ssrn.3383734. ISSN 1556-5068.
XBT satisfies the norm 'ISO 4217' by the International Organisation for Standardisation (ISO) as BTC goes against the name of Bhutan's currency. In general, transaction instruments that are not national currencies, like gold or silver, begin with an X. However, the symbol XBT is not officially recognised by ISO.
- Romain Dillet (9 August 2013). "Bitcoin Ticker Available On Bloomberg Terminal For Employees". TechCrunch. Archived from the original on 1 November 2014. Retrieved 2 November 2014.
- Bustillos, Maria (2 April 2013). "The Bitcoin Boom". The New Yorker. Archived from the original on 27 July 2014. Retrieved 22 December 2013.
- Bitcoin, Oxford Advanced Learner's Dictionary
- bitcoin Archived 3 May 2022 at the Wayback Machine, Cambridge Advanced Learner's Dictionary
- Katie Pisa; Natasha Maguder (9 July 2014). "Bitcoin your way to a double espresso". CNN. Archived from the original on 18 June 2015. Retrieved 23 April 2015.
- ^ Gervais, Arthur; Karame, Ghassan O.; Capkun, Vedran; Capkun, Srdjan (May 2014). "Is Bitcoin a Decentralized Currency?". IEEE Security & Privacy. 12 (3): 54–60. doi:10.1109/MSP.2014.49. ISSN 1540-7993. S2CID 13948781. Archived from the original on 19 November 2023. Retrieved 22 November 2023.
- ^ "The great chain of being sure about things". The Economist. 31 October 2015. Archived from the original on 4 December 2023. Retrieved 22 November 2023.
- "Blockchain Networks: Token Design and Management Overview" (PDF). National Institute of Standards Technology (NIST). p. 32. Archived (PDF) from the original on 24 December 2022. Retrieved 29 December 2022.
- Sparkes, Matthew (9 June 2014). "The coming digital anarchy". The Daily Telegraph. Archived from the original on 23 January 2015. Retrieved 7 January 2015.
- ^ Kroll, Joshua A.; Davey, Ian C.; Felten, E. (11–12 June 2013). The Economics of Bitcoin Mining, or Bitcoin in the Presence of Adversaries. The Twelfth Workshop on the Economics of Information Security (WEIS 2013). Washington, DC. S2CID 2794725.
- "Man Throws Away 7,500 Bitcoins, Now Worth $7.5 Million". CBS DC. 29 November 2013. Archived from the original on 15 January 2014. Retrieved 23 January 2014.
- Krause, Elliott (5 July 2018). "A Fifth of All Bitcoin Is Missing. These Crypto Hunters Can Help". The Wall Street Journal. Archived from the original on 9 July 2018. Retrieved 8 July 2018.
- Jeffries, Adrianne (19 December 2013). "How to steal Bitcoin in three easy steps". The Verge. Archived from the original on 27 July 2019. Retrieved 17 January 2014.
- Harney, Alexandra; Stecklow, Steve (16 November 2017). "Twice burned – How Mt. Gox's bitcoin customers could lose again". Reuters. Archived from the original on 29 August 2019. Retrieved 6 September 2018.
- ^ Mingxiao, Du; Xiaofeng, Ma; Zhe, Zhang; Xiangwei, Wang; Qijun, Chen (5–8 October 2017). A review on consensus algorithm of blockchain. 2017 IEEE International Conference on Systems, Man, and Cybernetics (SMC). Banff, AB, Canada: IEEE. pp. 2567–2572. doi:10.1109/SMC.2017.8123011. ISBN 978-1-5386-1645-1. Archived from the original on 24 November 2023. Retrieved 29 November 2023.
- "Bitcoin boom benefiting TSMC: report". Taipei Times. 4 January 2014. Archived from the original on 29 January 2023. Retrieved 22 October 2021.
- Ashlee, Vance (14 November 2013). "2014 Outlook: Bitcoin Mining Chips, a High-Tech Arms Race". BusinessWeek. Archived from the original on 21 November 2013. Retrieved 24 November 2013.
- King, Ritchie S.; Williams, Sam; Yanofsky, David (17 December 2013). "By reading this article, you're mining bitcoins". Quartz. Archived from the original on 17 December 2013. Retrieved 17 December 2013.
- Hampton, Nikolai (5 September 2016). "Understanding the blockchain hype: Why much of it is nothing more than snake oil and spin". Computerworld. Archived from the original on 6 September 2016. Retrieved 5 September 2016.
- Stoll, Christian; Klaaßen, Lena; Gallersdörfer, Ulrich; Neumüller, Alexander (June 2023). Climate Impacts of Bitcoin Mining in the U.S. (Report). Working Paper Series. MIT Center for Energy and Environmental Policy Research. Archived from the original on 18 November 2023. Retrieved 24 November 2023.
- Messina, Irene (31 August 2023). "Bitcoin electricity consumption: an improved assessment". Cambridge Judge Business School. Archived from the original on 7 September 2023. Retrieved 7 September 2023.
- ^ de Vries, Alex; Gallersdörfer, Ulrich; Klaaßen, Lena; Stoll, Christian (16 March 2022). "Revisiting Bitcoin's carbon footprint". Joule. 6 (3): 499. Bibcode:2022Joule...6..498D. doi:10.1016/j.joule.2022.02.005. ISSN 2542-4351. S2CID 247143939.
- Huang, Jon; O'Neill, Claire; Tabuchi, Hiroko (3 September 2021). "Bitcoin Uses More Electricity Than Many Countries. How Is That Possible?". The New York Times. ISSN 0362-4331. Archived from the original on 17 February 2023. Retrieved 16 January 2022.
- ^ de Vries, Alex; Stoll, Christian (December 2021). "Bitcoin's growing e-waste problem". Resources, Conservation and Recycling. 175: 105901. Bibcode:2021RCR...17505901D. doi:10.1016/j.resconrec.2021.105901. ISSN 0921-3449. S2CID 240585651. Archived from the original on 23 November 2021. Retrieved 24 November 2023.
- Simonite, Tom (5 September 2013). "Mapping the Bitcoin Economy Could Reveal Users' Identities". MIT Technology Review. Archived from the original on 27 September 2020. Retrieved 2 April 2014.
- Lee, Timothy (21 August 2013). "Five surprising facts about Bitcoin". The Washington Post. Archived from the original on 9 July 2022. Retrieved 21 November 2023.
- McMillan, Robert (6 June 2013). "How Bitcoin lets you spy on careless companies". Wired UK. Archived from the original on 9 February 2014. Retrieved 3 April 2020.
- Anderson, Ross; Shumailov, Ilia; Ahmed, Mansoor (24 November 2018). "Making Bitcoin Legal". In Matyáš, Vashek; Švenda, Petr; Stajano, Frank; Christianson, Bruce (eds.). Security Protocols XXVI. Lecture Notes in Computer Science. Vol. 11286. Springer. pp. 243–253. doi:10.1007/978-3-030-03251-7_29. ISBN 978-3-030-03250-0. Archived from the original on 24 November 2023. Retrieved 24 November 2023.
- Möser, Malte; Böhme, Rainer; Breuker, Dominic (2013). An Inquiry into Money Laundering Tools in the Bitcoin Ecosystem (PDF). 2013 APWG eCrime Researchers Summit. IEEE. ISBN 978-1-4799-1158-5. Archived (PDF) from the original on 26 June 2018. Retrieved 19 June 2019.
- Serwer, Adam; Liebelson, Dana (10 April 2013). "Bitcoin, Explained". Mother Jones. Archived from the original on 27 April 2014. Retrieved 26 April 2014.
- Vigna, Paul (17 January 2016). "Is Bitcoin Breaking Up?". The Wall Street Journal. Archived from the original on 20 August 2016. Retrieved 8 November 2016.
- Gervais, Arthur; Capkun, Srdjan; Karame, Ghassan O.; Gruber, Damian (8 December 2014). "On the privacy provisions of Bloom filters in lightweight bitcoin clients". Proceedings of the 30th Annual Computer Security Applications Conference. ACSAC '14. New York, NY, USA: Association for Computing Machinery. pp. 326–335. doi:10.1145/2664243.2664267. ISBN 978-1-4503-3005-3. S2CID 9161497. Archived from the original on 21 April 2024. Retrieved 22 November 2023.
- Barhydt, Bill (4 June 2014). "3 reasons Wall Street can't stay away from bitcoin". CNBC. Archived from the original on 4 December 2023. Retrieved 22 November 2023.
- Roberts, Daniel (15 December 2017). "How to send bitcoin to a hardware wallet". Yahoo Finance. Archived from the original on 17 February 2018. Retrieved 17 February 2018.
- Mike Orcutt (19 May 2015). "Leaderless Bitcoin Struggles to Make Its Most Crucial Decision". MIT Technology Review. Archived from the original on 18 October 2017. Retrieved 15 November 2016.
- Orcutt, Mike (19 May 2015). "Leaderless Bitcoin Struggles to Make Its Most Crucial Decision". MIT Technology Review. Archived from the original on 18 October 2017. Retrieved 22 June 2017.
- Tschorsch, Florian; Scheuermann, Björn (2016). "Bitcoin and Beyond: A Technical Survey on Decentralized Digital Currencies". IEEE Communications Surveys and Tutorials. 18 (3): 2084–2123. doi:10.1109/comst.2016.2535718. S2CID 5115101.
- Wilhelm, Alex. "Popular Bitcoin Mining Pool Promises To Restrict Its Compute Power To Prevent Feared '51%' Fiasco". TechCrunch. Archived from the original on 5 December 2017. Retrieved 25 January 2018.
- European Central Bank (2012). Virtual Currency Schemes (PDF). European Central Bank. doi:10.2866/47380. ISBN 978-92-899-0862-7. OCLC 1044382974. Archived (PDF) from the original on 6 November 2012.
- Dodd, Nigel (May 2018). "The Social Life of Bitcoin" (PDF). Theory, Culture & Society. 35 (3): 35–56. doi:10.1177/0263276417746464. ISSN 0263-2764. S2CID 51914607. Archived (PDF) from the original on 22 November 2023. Retrieved 22 November 2023.
- ^ "Bitcoin and other cryptocurrencies are useless". The Economist. 30 August 2018. Archived from the original on 4 September 2018. Retrieved 4 September 2018.
- Feuer, Alan (14 December 2013). "The Bitcoin Ideology". The New York Times. Archived from the original on 1 July 2018. Retrieved 1 July 2018.
- ^ Mohamed, Theron (30 May 2023). "Nobel economist Paul Krugman slams crypto as mostly useless, after saying it's hugely overpriced and helps criminals". Business Insider. Archived from the original on 23 November 2023. Retrieved 23 November 2023.
- ^ "Free Exchange. Money from nothing. Chronic deflation may keep Bitcoin from displacing its rivals". The Economist. 15 March 2014. Archived from the original on 25 March 2014. Retrieved 25 March 2014.
- "The magic of mining". The Economist. 13 January 2015. Archived from the original on 12 January 2015. Retrieved 13 January 2015.
- Shiller, Robert (1 March 2014). "In Search of a Stable Electronic Currency". The New York Times. Archived from the original on 24 October 2014.
- Velde, François (December 2013). "Bitcoin: A primer" (PDF). Chicago Fed letter. Federal Reserve Bank of Chicago. p. 4. Archived (PDF) from the original on 26 October 2014. Retrieved 3 September 2016.
- Wile, Rob (6 April 2014). "St. Louis Fed Economist: Bitcoin Could Be A Good Threat To Central Banks". Business Insider. Archived from the original on 24 September 2015. Retrieved 16 April 2014.
- Weindling, Jacob (18 September 2017). "China May Be Gearing Up to Ban Bitcoin". Paste. Archived from the original on 22 November 2023. Retrieved 22 November 2023.
- Lavin, Tim (8 August 2013). "The SEC Shows Why Bitcoin Is Doomed". Bloomberg News. Archived from the original on 25 March 2014. Retrieved 20 October 2013.
- Montag, Ali (9 July 2018). "Nobel-winning economist: Authorities will bring down 'hammer' on bitcoin". CNBC. Archived from the original on 11 July 2018. Retrieved 11 July 2018.
- "Regulation of Cryptocurrency Around the World: November 2021 Update" (PDF). United States Library of Congress. Archived (PDF) from the original on 24 December 2021. Retrieved 28 December 2022.
- ^ Murphy, Hannah (8 June 2018). "Who really owns bitcoin now?". Financial Times. Archived from the original on 10 June 2018. Retrieved 10 June 2018.
- "Monetarists Anonymous". The Economist. 29 September 2012. ISSN 0013-0613. Archived from the original on 1 September 2022. Retrieved 22 November 2023.
- Ball, James (22 March 2013). "Silk Road: the online drug marketplace that officials seem powerless to stop". The Guardian. ISSN 0261-3077. Archived from the original on 12 October 2013. Retrieved 22 November 2023.
- Katz, Lily (12 July 2017). "Bitcoin Acceptance Among Retailers Is Low and Getting Lower". Bloomberg News. Archived from the original on 25 January 2018. Retrieved 25 January 2018.
- Kharif, Olga (1 August 2018). "Bitcoin's Use in Commerce Keeps Falling Even as Volatility Eases". Bloomberg News. Archived from the original on 2 August 2018. Retrieved 2 August 2018.
- Chan, Bernice (16 January 2015). "Bitcoin transactions cut the cost of international money transfers". South China Morning Post. Archived from the original on 31 May 2019. Retrieved 31 May 2019.
- Sheidlower, Noah (11 April 2022). "Bitcoin by bitcoin, restaurants start to accept cryptocurrencies". NBC News. Retrieved 7 October 2024.
- "Majority of Salvadorans do not want bitcoin, poll shows". Reuters. 2 September 2021. Archived from the original on 30 November 2021. Retrieved 30 November 2021.
- "IMF urges El Salvador to remove Bitcoin as legal tender". BBC News. 26 January 2022. Archived from the original on 26 January 2022. Retrieved 26 January 2022.
- Alvarez, Fernando; Argente, David; Van Patten, Diana (2022). Are Cryptocurrencies Currencies? Bitcoin as Legal Tender in El Salvador (Report). Cambridge, MA: National Bureau of Economic Research. doi:10.3386/w29968.
- "Bitcoin Declared Legal Currency in Central African Republic". Bloomberg. 28 April 2022. Archived from the original on 28 April 2022. Retrieved 28 April 2022.
- "Frequently Asked Questions on Central African Republic". International Monetary Fund. Archived from the original on 11 August 2023. Retrieved 11 August 2023.
- Rasool, Mohammed (3 November 2020). "Iran Is Pivoting to Bitcoin". Vice. Archived from the original on 3 November 2020. Retrieved 10 November 2020.
- "Iran: New Crypto Law Requires Selling Bitcoin Directly to Central Bank to Fund Imports". Asharq Al-Awsat. 31 October 2020. Archived from the original on 31 October 2020. Retrieved 31 October 2020.
- Kohler, Judith (21 September 2022). "Colorado accepts cryptocurrency to pay taxes, moving the state "tech forward"". The Denver Post. Archived from the original on 29 December 2022. Retrieved 29 December 2022.
- "'Crypto Valley' canton to accept Bitcoin for tax payments". SWI swissinfo. 3 September 2020. Archived from the original on 22 November 2023. Retrieved 22 November 2023.
- Huang, Vicky Ge (15 October 2023). "Why the U.S. Government Has $5 Billion in Bitcoin". The Wall Street Journal. Archived from the original on 20 February 2024. Retrieved 20 February 2024.
- Castillo, Michael del (16 June 2023). "U.S. Government Owns Way More Bitcoin Than Any Other Country–So Why Aren't They Selling It?". Forbes. Archived from the original on 21 February 2024. Retrieved 21 February 2024.
- "Jersey approve Bitcoin fund launch on island". BBC News. 10 July 2014. Archived from the original on 10 July 2014. Retrieved 10 July 2014.
- "Chicago Mercantile Exchange jumps into bitcoin futures". CBS News. 18 December 2017. Archived from the original on 31 May 2019. Retrieved 31 May 2019.
- "Gold or Bitcoin? Store-of-value debate rages as Bitcoin grows". Bloomberg Professional Services. 25 October 2021. Retrieved 2 October 2024.
- "Goldman Sachs says bitcoin will compete with gold as "store of value"". Reuters. 5 January 2022.
- Lee, Timothy B. "The $11 million in bitcoins the Winklevoss brothers bought is now worth $32 million". The Washington Post. Archived from the original on 6 July 2017. Retrieved 11 August 2017.
- Maidenberg, Micah; Driebusch, Corrie; Jin, Berber (17 August 2023). "A Rare Look Into the Finances of Elon Musk's Secretive SpaceX". The Wall Street Journal. Archived from the original on 17 August 2023. Retrieved 19 November 2023.
- Ostroff, Caitlin; Elliott, Rebecca (8 February 2021). "Tesla Buys $1.5 Billion in Bitcoin". The Wall Street Journal. ISSN 0099-9660. Archived from the original on 6 January 2024. Retrieved 22 November 2023.
- Vigna, Paul (20 December 2021). "Bitcoin's 'One Percent' Controls Lion's Share of the Cryptocurrency's Wealth". Wall Street Journal. ISSN 0099-9660. Archived from the original on 22 December 2021. Retrieved 22 December 2021.
- Cota, Isabella (2 September 2023). "Two years of bitcoin in Bukele's El Salvador: An opaque experiment with a little-used currency". El País. Archived from the original on 24 November 2023. Retrieved 24 November 2023.
- Gandal, Neil; Hamrick, J.T.; Moore, Tyler; Oberman, Tali (May 2018). "Price manipulation in the Bitcoin ecosystem". Journal of Monetary Economics. 95: 86–96. doi:10.1016/j.jmoneco.2017.12.004. S2CID 26358036.
- Griffin, John M.; Shams, Amin (August 2020). "Is Bitcoin Really Untethered?". The Journal of Finance. 75 (4): 1913–1964. doi:10.1111/jofi.12903. ISSN 0022-1082. S2CID 229576274.
- Popper, Nathaniel (13 June 2018). "Bitcoin's Price Was Artificially Inflated Last Year, Researchers Say". The New York Times. Archived from the original on 13 June 2018. Retrieved 13 June 2018.
- Costelloe, Kevin (29 November 2017). "Bitcoin 'Ought to Be Outlawed,' Nobel Prize Winner Stiglitz Says". Bloomberg News. Archived from the original on 12 June 2018. Retrieved 5 June 2018.
It doesn't serve any socially useful function.
- Authers, John (9 June 2021). "Don't Call Bitcoin a Bubble. It's an Epidemic". Bloomberg.com. Archived from the original on 10 June 2021.
- Tirole, Jean (1 February 2024). "Cryptocurrencies: an economist's view". La Jaune et la Rouge. Vol. February 2024, no. 792. Retrieved 15 November 2024.
- "Bitcoin breaks $100,000 barrier amid post-election cryptocurrency surge". Washington Post. Retrieved 5 December 2024.
"People use bitcoin as a speculative asset. It's like gold, it's just like gold, only it's virtual, it's digital. People are not using it as a form of payment or a store of value," he said. "It's highly volatile. It's not a competitor for the dollar; it's really a competitor for gold."
- Klein, Tony; Pham Thu, Hien; Walther, Thomas (October 2018). "Bitcoin is not the New Gold – A comparison of volatility, correlation, and portfolio performance" (PDF). International Review of Financial Analysis. 59: 105–116. doi:10.1016/j.irfa.2018.07.010. S2CID 158400153. Archived (PDF) from the original on 25 November 2023. Retrieved 24 November 2023.
- Mazur, Mieszko (31 March 2022). "Misperceptions of Bitcoin Volatility". The Journal of Alternative Investments. 24 (4): 33–44. doi:10.3905/jai.2022.1.153. ISSN 1520-3255. S2CID 247843794.
- Montag, Ali (26 August 2018). "'HODL,' 'whale' and 5 other cryptocurrency slang terms explained". CNBC. Archived from the original on 12 January 2022. Retrieved 16 March 2021.
- Hajric, Vildana (19 November 2020). "All the Bitcoin Lingo You Need to Know as Crypto Heats Up". Bloomberg. Archived from the original on 29 November 2020. Retrieved 1 December 2020.
- Clinch, Matt (10 March 2014). "Roubini launches stinging attack on bitcoin". CNBC. Archived from the original on 9 July 2022. Retrieved 22 November 2023.
- "This Billionaire Just Called Bitcoin a 'Pyramid Scheme'". Fortune. Archived from the original on 24 September 2017. Retrieved 23 September 2017.
- Ott Ummelas; Milda Seputyte (31 January 2014). "Bitcoin 'Ponzi' Concern Sparks Warning From Estonia Bank". Bloomberg News. Archived from the original on 29 March 2014. Retrieved 1 April 2014.
- Posner, Eric (11 April 2013). "Fool's Gold". Slate. ISSN 1091-2339. Archived from the original on 8 July 2022. Retrieved 22 November 2023.
- Davradakis, Emmanouil; Santos, Ricardo (2019). Blockchain, FinTechs and their relevance for international financial institutions. European Investment Bank. doi:10.2867/11329. ISBN 978-92-861-4184-3. Archived from the original on 21 April 2024. Retrieved 24 November 2023.
Further reading
- Nakamoto, Satoshi (31 October 2008). "Bitcoin: A Peer-to-Peer Electronic Cash System" (PDF). bitcoin.org. Archived from the original (PDF) on 20 March 2014. Retrieved 28 April 2014.
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