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*For Chronicle of Higher Ed, see {{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> This article follows the latter convention.}} Payments work [[peer-to-peer]] without a central repository or single administrator, which has led the [[US Treasury]] to call bitcoin a decentralized [[virtual currency]].<ref name="JSC">{{cite web | url=http://www.fincen.gov/news_room/testimony/html/20131119.html | 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=November 19, 2013 | accessdate=1 June 2014}}</ref> Although its status as a currency is disputed, media reports often refer to bitcoin as a [[cryptocurrency]] or [[digital currency]].<ref name="currencydispute"/>
*For Chronicle of Higher Ed, see {{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> This article follows the latter convention.}} Payments work [[peer-to-peer]] without a central repository or single administrator, which has led the [[US Treasury]] to call bitcoin a decentralized [[virtual currency]].<ref name="JSC">{{cite web | url=http://www.fincen.gov/news_room/testimony/html/20131119.html | 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=November 19, 2013 | accessdate=1 June 2014}}</ref> Although its status as a currency is disputed, media reports often refer to bitcoin as a [[cryptocurrency]] or [[digital currency]].<ref name="currencydispute"/>


Bitcoins are created as a virtual product in reward for payment processing work, in which users offer their computing power to verify and record payments into a public ledger. Called mining, individuals or companies engage in this activity in exchange for 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 | author=Jerry Brito and Andrea Castillo|page=5}}</ref> Besides mining, bitcoins can be obtained in exchange for [[fiat money]], products, and services.<ref name="4_main_ways_to_get_Bitcoin">{{cite news | url=http://www.bitcoinbulletin.com/2011/03/11/how-do-i-get-bitcoins/ | title=How do I get Bitcoins? (For Beginners) | work=The Bitcoin Bulletin | date=11 March 2011 | accessdate=13 December 2013}}</ref> Users can send and receive bitcoins electronically for an optional transaction fee<ref name="EconOfBTC">{{cite web | url=http://www.weis2013.econinfosec.org/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)
Bitcoins are created as a reward for payment processing work in which users offer their computing power to verify and record payments into the public ledger. Called mining, individuals or companies engage in this activity in exchange for 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 | author=Jerry Brito and Andrea Castillo|page=5}}</ref> Besides mining, bitcoins can be obtained in exchange for [[fiat money]], products, and services.<ref name="4_main_ways_to_get_Bitcoin">{{cite news | url=http://www.bitcoinbulletin.com/2011/03/11/how-do-i-get-bitcoins/ | title=How do I get Bitcoins? (For Beginners) | work=The Bitcoin Bulletin | date=11 March 2011 | accessdate=13 December 2013}}</ref> Users can send and receive bitcoins electronically for an optional transaction fee<ref name="EconOfBTC">{{cite web | url=http://www.weis2013.econinfosec.org/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=8 May 2014 | author=Joshua A. Kroll, Ian C. Davey, Edward W. Felten
| date= 11–12 June 2013 | accessdate=8 May 2014 | author=Joshua A. Kroll, Ian C. Davey, Edward W. Felten
| quote="If the value paid out of a transaction (in Bitcoins) is less than the amount put in, the difference is treated as a transaction fee that can be collected by whoever manages to mine a block containing that transaction. A transaction
| quote="If the value paid out of a transaction (in Bitcoins) is less than the amount put in, the difference is treated as a transaction fee that can be collected by whoever manages to mine a block containing that transaction. A transaction

Revision as of 13:08, 29 July 2014

Bitcoin
A common logo from the bitcoin reference client
Unit
Symbol BTC, XBT,[1]
Denominations
Subunit
10−8satoshi[2]
10−6bit or μBTC
10−3mBTC
Demographics
Date of introduction3 January 2009; 15 years ago (2009-01-03)
User(s)Worldwide
Valuation
Production25 bitcoins per block (approximately every ten minutes) until mid 2016,[3] and then afterwards 12.5 bitcoins per block for 4 years until next halving. This halving continues until 2110-2140 when 21 million bitcoins have been issued.
 SourceNumber of bitcoins in circulation
 MethodIncrease in the supply

Bitcoin is a software-based online payment system described by Satoshi Nakamoto[note 1] in 2008[4] and introduced as open-source software in 2009.[5] Payments are recorded in a public ledger using its own unit of account,[6] which is also called bitcoin.[note 2] Payments work peer-to-peer without a central repository or single administrator, which has led the US Treasury to call bitcoin a decentralized virtual currency.[9] Although its status as a currency is disputed, media reports often refer to bitcoin as a cryptocurrency or digital currency.[10]

Bitcoins are created as a reward for payment processing work in which users offer their computing power to verify and record payments into the public ledger. Called mining, individuals or companies engage in this activity in exchange for transaction fees and newly created bitcoins.[11] Besides mining, bitcoins can be obtained in exchange for fiat money, products, and services.[12] Users can send and receive bitcoins electronically for an optional transaction fee[13] using wallet software on a personal computer, mobile device, or a web application.

Bitcoin as a form of payment for products and services has seen growth,[14] and merchants have an incentive to accept the digital currency because fees are lower than the 2–3% typically imposed by credit card processors.[15] The European Banking Authority has warned that bitcoin lacks consumer protections.[16] Unlike credit cards, any fees are paid by the purchaser not the vendor. Bitcoins can be stolen and chargebacks are impossible.[17] Commercial use of bitcoin is currently small compared to its use by speculators, which has fueled price volatility.[18]

Bitcoin has been a subject of scrutiny amid concerns that it can be used for illegal activities.[19] In October 2013 the US FBI shut down the Silk Road online black market and seized 144,000 bitcoins worth US$28.5 million at the time.[20] The US is considered bitcoin-friendly compared to other governments.[21] In China, buying bitcoins with yuan is subject to restrictions, and bitcoin exchanges are not allowed to hold bank accounts.

Overview

The most important part of the bitcoin system is a public ledger that records financial transactions in bitcoins. This is accomplished without the intermediation of any single, central authority, as long as mining is decentralized. Instead, multiple intermediaries exist in the form of computer servers running bitcoin software. By connecting over the Internet, these servers form a network that anyone can join. Transactions of the form payer X wants to send Y bitcoins to payee Z are broadcast to this network using readily available software applications. Bitcoin servers can validate these transactions, add them to their copy of the ledger, and then broadcast these ledger additions to other servers.[22]

The block chain ledger

All bitcoin transfers are recorded in a computer file that acts as a public ledger called the block chain, which everyone can examine. Where a conventional ledger records the transfer of actual bills or promissory notes that exist apart from it, bitcoins are simply entries in the block chain and do not exist outside of it.[23]

Mining

Obsolete bitcoin mining hardware common in mid and late 2013. Called USB Block Erupter, each can calculate ~333 megahashes per second.

Maintaining the block chain is called mining, and those who do are rewarded with newly created bitcoins and transaction fees.[24] Miners may be located anywhere in the world; they process payments by verifying each transaction as valid and adding it to the block chain.[24] As of 2014, payment processing is rewarded with 25 newly created bitcoins per block added to the block chain. To claim the reward, a special transaction called a coinbase is included with the processed payments.[22] All bitcoins in circulation can be traced back to such coinbase transactions. The bitcoin protocol specifies that the reward for adding a block will be halved approximately every four years. Eventually, the reward will be removed entirely when an arbitrary limit of 21 million bitcoins is reached c. 2140, and transaction processing will then be rewarded by transaction fees solely.[25] Paying a transaction fee is optional, but may speed up confirmation of the transaction.[26] Payers have an incentive to include such fees because doing so means their transaction will likely be added to the block chain sooner; miners can choose which transactions to process[13] and prefer to include those that pay fees.

As of 2013 mining had become quite competitive, has been compared to an arms race and ever more specialized technology is utilized. The most efficient mining hardware makes use of custom designed application-specific integrated circuits, which outperform general purpose CPUs and use less power as well.[27] Without access to these purpose built machines, a bitcoin miner is unlikely to earn enough to even cover the cost of the electricity used in his or her efforts.[28]

Mining pools

The individual odds of winning the reward for adding a block to the block chain decrease with an increasing number of miners. Since the reward for each block can only go to a single bitcoin address, As of 2014, it has become common for miners to join organized mining pools,[29] which split work and reward among all participants and make mining a less risky endeavor. Even for those who join pools, the cost of the electricity necessary to mine may outweigh the bitcoin rewards from doing so.[28]

Anonymity

The public nature of bitcoin means that, while those who use it are not identified by name, transactions can be linked to individuals and companies.[30] All transactions are recorded into a public ledger, the block chain, and are viewable by everyone. Additionally, many jurisdictions require exchanges, where people can buy and sell bitcoins for cash, to collect personal information.[31] The privacy concerns of some who use bitcoins are sufficient to cause them to take additional steps to cover their tracks. In order to obfuscate the link between individual and transaction, a different bitcoin address for each transaction can be used, and others rely on so-called mixing services that allow users to trade bitcoins whose transaction history implicates them for coins with different transaction histories.[32]

It has been suggested that bitcoin payments should not be considered more anonymous than credit card payments.[33]

Buying and selling

Bitcoins can be bought and sold with many different currencies from individuals and companies. Bitcoins may be purchased in person or at a bitcoin ATM in exchange for cash currency.[34] Participants in online exchanges offer bitcoin buy and sell bids. Using an online exchange to obtain bitcoins entails some risk, and according to one study, 45% of exchanges fail and take client bitcoins with them.[35] Since bitcoin transactions are irreversible, sellers of bitcoins must take extra measures to ensure they have received traditional funds from the buyer.

Wallets

Example of Casascius physical bitcoins[36]
A paper wallet with QR codes

While wallets are often described as being a place to hold or store bitcoins,[37] due to the nature of the system, bitcoins are inseparable from the block chain transaction ledger. Perhaps a better way to define a wallet is something "that stores the digital credentials for your bitcoin holdings"[38] and allows you to access (and spend) them. Bitcoin uses public-key cryptography, in which two cryptographic keys, one public and one private, are generated.[39] The public key can be thought of as an account number or name and the private key, ownership credentials. At its most basic, a wallet is a collection of these keys. Most bitcoin software also includes the ability to make transactions, however.

Perhaps better termed physical wallets, physical bitcoins are ubiquitous in media coverage and combine a novelty coin with a private key printed on paper, metal,[40] wood,[41] or plastic. Physical bitcoins aren't widely seen outside of pictures in news article[citation needed], but for those serious about security, storing private keys on paper printouts or in offline data storage devices is the best option.[38]

Software
Electrum – sample bitcoin client

Bitcoin client software called a bitcoin wallet allows a user to transact bitcoins. A wallet program generates and stores private keys, and communicates with peers on the bitcoin network. The first wallet program called Bitcoin-Qt was released in 2009 by Satoshi Nakamoto as open source code.[42] It can be used as a desktop wallet for payments or as a server utility for merchants and other payment services. Bitcoin-Qt, also called Satoshi client, is sometimes referred to as the reference client because it serves to define the bitcoin protocol and acts as a standard for other implementations.[42] As of version 0.9, Bitcoin-Qt has been renamed Bitcoin Core to more accurately describe its role in the network.[43] When making a purchase with a mobile device, QR codes are used ubiquitously to simplify transactions. Several server software implementations of the bitcoin protocol exist. So-called full nodes on the network validate transactions and blocks they receive, and relay them to connected peers.[42]

Ownership

The ownership of bitcoins associated with a certain bitcoin address can be demonstrated with knowledge of the private key belonging to the address. For the owner, it is important to protect the private key from loss or theft. If a private key is lost, the user cannot prove ownership by other means. The coins are then lost and cannot be recovered. Because anyone with knowledge of the private key can take ownership of any associated bitcoins, theft can occur when a private key is revealed or stolen.[18]

Security, theft, and loss

Integral to bitcoin security is the prevention of unauthorized transactions from an individual's wallet. A bitcoin transaction permanently transfers ownership to a new address, a string having the form of random letters and numbers derived from public keys by application of a hash function and encoding scheme. The corresponding private keys act as a safeguard for the owner; a valid payment message from an address must contain the associated public key and a digital signature proving possession of the associated private key. Because anyone with a private key can spend all of the bitcoins associated with the corresponding address, protection of private keys is quite important. Loss of a private key may result in theft, which has occurred on numerous occasions.[44] The practical day-to-day security of bitcoin wallets is an ongoing concern.[45] Risk of theft can be reduced by generating keys offline on an uncompromised computer and saving them on external storage or paper printouts.[46]

Bitcoins can be lost. In 2013 one user said he lost 7,500 bitcoins, worth $7.5m at the time, when he discarded a hard drive containing his private key.[47] Bitcoins can also be found. In March 2014, former bitcoin exchange Mt. Gox reported it found an "old wallet, which was used before June 2011 [that] held about 200,000 bitcoins".[48]

History

Bitcoin was first mentioned in a 2008 research paper published under the name Satoshi Nakamoto. It is unknown who Satoshi Nakamoto is. In 2009, an exploit in an early bitcoin client was found that allowed large numbers of bitcoins to be created.[49]

In March 2013, a technical glitch caused a fork in the block chain, 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. Normal operation was restored when the majority of the network downgraded to version 0.7 of the bitcoin software.[49]

Some mainstream websites began accepting bitcoins c. 2013. WordPress started in November 2012[50] followed by OKCupid in April 2013,[51] Atomic Mall in November 2013,[52] TigerDirect[53] and Overstock.com in January 2014,[54] Expedia in June 2014,[55] and Newegg in July 2014. Certain non-profit or advocacy groups such as the Electronic Frontier Foundation allow bitcoin donations.[56] (Although this organization stopped accepting bitcoins in 2011 and began again in 2013.[57])

The first law enforcement events occurred in May 2013. Assets belonging to the Mt. Gox exchange were seized by Department of Homeland Security,[58] and the Silk Road drug market website was shut down by the FBI.[59]

In October 2013, Chinese internet giant Baidu had allowed clients of website security services to pay with bitcoins.[60] During November 2013, the China-based bitcoin exchange BTC China overtook the Japan-based Mt. Gox and the Europe-based Bitstamp to become the largest bitcoin trading exchange by trade volume.[61] 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 that virtual currencies were a legitimate financial service.[62] On the same day, one bitcoin traded for over RMB¥6780 (US$1100) in China.[63] On 5 December 2013, the People's Bank of China prohibited Chinese financial institutions from using bitcoins.[64] After the announcement, the value of bitcoins dropped[65] and Baidu no longer accepted bitcoins for certain services.[66] Buying real-world goods with any virtual currency had been illegal in China since at least 2009.[67]

The first bitcoin ATM was installed in October 2013 in Vancouver, British Columbia, Canada.[68]

With roughly 12 million existing bitcoins As of November 2013,[69] the new price increased the market cap for bitcoin to at least US$7.2 billion.[70] By 23 November 2013, the total market capitalization of bitcoin exceeded US$10 billion for the first time.[71]

In the US two men were arrested in January 2014 on charges of money-laundering using bitcoins including Charlie Shrem, the head of defunct bitcoin exchange BitInstant and a vice chairman of the Bitcoin Foundation. Shrem allegedly allowed the other arrested party to purchase large quantities of bitcoins for use on black-market websites.[72]

In early February 2014, one of the largest bitcoin exchanges, Mt. Gox, suspended withdrawals citing technical issues.[73] By the end of the month, Mt. Gox had filed for bankruptcy protection in Japan amid reports that 744,000 bitcoins had been stolen.[74] Originally a site for trading Magic: The Gathering cards, Mt. Gox once was the dominant bitcoin exchange although prior to the collapse its popularity had waned.[75]

Economics

Classification

Bitcoin is commonly referred to as digital currency,[11] digital cash,[76] virtual currency,[2] electronic currency,[7] or cryptocurrency.[1] Some media outlets do make a distinction between "real" money and bitcoins, however.[77] According to the director of the Institute for Money, Technology and Financial Inclusion at the University of California-Irvine there is "an unsettled debate about whether bitcoin is a currency or payment protocol".[10]

Economists defining money as a store of value, a medium of exchange, and a unit of account agree that bitcoin has some way to go to meet all these criteria.[78] It does best as a medium of exchange.[78] (About 1,000 bricks and mortar businesses were willing to accept payment in bitcoins as of November 2013[79] in addition to more than 35,000 online merchants.[80]) The bitcoin market currently suffers from volatility, limiting the ability of bitcoins to act as a stable store of value,[78] and, although bitcoin is the unit of account for the block chain, bitcoin does not see use as a unit of account outside of it. Where people are allowed to buy with bitcoins, prices are not denominated in bitcoins.[78]

The People's Bank of China has stated that bitcoin "is fundamentally not a currency".[81]

Price and volatility

To improve access to price information and increase transparency, on 30 April 2014 Bloomberg LP announced plans to list prices from bitcoin companies Kraken and Coinbase on its 320.000 subscription financial data terminals.[82]

According to Mark T. Williams of Boston University, the volatility of bitcoin is over seven times that of gold and over eight times that of the S&P 500.[83] The Bitcoin Foundation contends that high volatility is due to insufficient liquidity[84] while a Forbes journalist claims that it is related to the uncertainty of its long-term value.[85] As of 2014, pro-bitcoin venture capitalists argue the greatly increased trading volume that planned high-frequency trading exchanges are hoped to bring will decrease price volatility.[82] Volatility has little effect on the utility of bitcoin as a payment processing system.[86]

The price of bitcoins has gone through various cycles of appreciation and depreciation referred to by some as bubbles and busts.[87] In 2011, the value of one bitcoin rapidly rose from about US$0.30 to US$32 before returning to US$2.[88] In the latter half of 2012 and during the 2012-2013 Cypriot Financial Crisis, the bitcoin price began to rise,[89] reaching a peak of US$266 on 10 April 2013, before crashing to around US$50.[90] At the end of 2013, the cost of one bitcoin rose to the all-round peak of US$1135, but fell to the price of US$693 three days later.[91][better source needed] In 2014 the price fell sharply, and in April remained depressed at little more than half that of 2013.[82]

Alternative to national currencies

Bitcoins are accepted in this café in the Netherlands as of 2013

Bitcoins are used by some Argentinians as an alternative to the official currency,[92] which is stymied by inflation and strict capital controls, to protect their savings against inflation or the possibility that governments could confiscate savings accounts.[93] It's been suggested that during the 2012–2013 Cypriot financial crisis bitcoin purchases rose due to fears that savings accounts would be confiscated or taxed.[94]

Speculative bubble

Bitcoin has been labelled a speculative bubble by many including Former Federal Reserve Chairman Alan Greenspan[95] and economist John Quiggin.[96] Two lead software developers of bitcoin, Gavin Andresen and Mike Hearn, have warned that bubbles may occur.[97] Nobel Laureate Robert Shiller said that bitcoin "exhibited many of the characteristics of a speculative bubble."[98] Others reject the label and see bitcoin's quick rise in price as nothing more than normal economic forces at work.[99]

As investment

One way of investing in bitcoins is to buy and hold them as a long-term, high-risk investment.[100] FINRA, a United States self-regulatory organization, warns that investing in bitcoins carries significant risks.[101] The European Banking Authority warns that the risks of investment go beyond a potential fall in the value of bitcoins.[102] Bitcoins may be of limited value to unsophisticated investors.[103] Risk hasn't deterred some such as the Winklevoss twins, who made a US$1.5 million personal investment[104] and attempted to launch a bitcoin ETF.[18] The first regulated bitcoin fund was established in Jersey in July 2014, with the approval of the Jersey Financial Services Commission.[105] Other investors, like Peter Thiel's Founders Fund, which invested US$3 million, don't purchase bitcoins themselves instead funding bitcoin infrastructure like companies that provide payment systems to merchants, exchanges, and wallet services, etc.[104] Investors also invest in bitcoin mining.[106]

Supply

Growth of the bitcoin supply is predefined by the bitcoin protocol.[25] Currently there are over twelve million bitcoins in circulation with an approximate creation rate of 25 every ten minutes. The total supply is capped at an arbitrary limit of 21 million,[11] and every four years the creation rate is halved. This means new bitcoins will continue to be released for more than a hundred years.

Value forecasts

Financial journalists and analysts, economists, and investors have attempted to predict the possible future value of bitcoin. Economist John Quiggin stated, "bitcoins will attain their true value of zero sooner or later, but it is impossible to say when."[96] In 2013, Bank of America FX and Rate Strategist David Woo forecast a maximum fair value per bitcoin of $1,300.[107] Bitcoin investor Cameron Winklevoss stated in 2013 that the "[s]mall bull case scenario for bitcoin is... 40,000 USD a coin".[108] In late 2013, finance professor Mark Williams forecast a bitcoin would be worth less than ten US dollars by July 2014.[109] Since then bitcoin have exchanged as low as $344 (April 2014) and during July 2014 the bitcoin low has been $609.[110]

On its political economy

The Nation suggested in May 2014, that it was "difficult to see what problem Bitcoin solves for people with left-wing politics.".[111]

Vasilis Kostakis and Michel Bauwens claim that bitcoin is a currency that reflects a new type of capitalism, named “distributed” capitalism.[112] and that this new capitalism conforms to characteristics of the network era and utilizes the peer-to-peer infrastructures to achieve capital accumulation.[113] According to Vasilis Kostakis it might appear as though it exists outside the financial system, but by promoting scarcity and competition this project aggravates the over-accumulation of capital and exacerbates the social inequalities that it is supposed to combat[dubiousdiscuss][114] According to Vasilis Kostakis[113][114] bitcoin should be viewed like a new technology, not just a currency: It has paved the way for new types of currencies that utilize new technological infrastructures and whose dynamics should not be ignored.

Reception

Some economists have responded positively to bitcoin, including François R. Velde, Senior Economist at the Chicago Fed, who described it as "an elegant solution to the problem of creating a digital currency."[115] Paul Krugman and Brad DeLong have found fault with bitcoin questioning why it should act as a reasonably stable store of value or whether there is a floor on their value.[116] Economist John Quiggin has criticized bitcoin as "the final refutation of the efficient-market hypothesis".[96]

David Andolfatto, a 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.[117]

Free software movement activist Richard Stallman has criticized the lack of anonymity and called for reformed development.[118] PayPal President David A. Marcus calls bitcoin a "great place to put assets" but claims it will not be a currency until price volatility is reduced.[119] As bitcoins proved popular, they have been increasingly covered by comics around the world.[120]

Acceptance by merchants

Established firms that accept bitcoins include Atomic Mall,[121] Clearly Canadian,[122] Dish Network, Overstock.com,[54] the Sacramento Kings,[123] TigerDirect,[53] Virgin Galactic,[124] Zynga,[125]Newegg.,[126] Expedia,[127] and Dell.[128]

In late 2013 the University of Nicosia became the first university in the world to accept it.[129]

Financial institutions

As of 2014, bitcoin companies have had difficulty opening traditional bank accounts because lenders have been leery of bitcoin's links to illicit activity.[130] According to a co-founder of one such company, BitPay, "banks are scared to deal with bitcoin companies, even if they really want to".[130] Yet, some financial institutions have been bullish on bitcoin. 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. As a medium of exchange, bitcoin has clear potential for growth and that in a long-term fair-value analysis maximum market capitalization for bitcoins could be $15 billion."[131] In June 2014, the first bank that converts deposits in currencies instantly to bitcoin without any fees, for further transactions, was opened in Boston.[132]

Concurrent with Bloomberg LP, 33% owned by Merrill Lynch launching pricing information is the development of high-frequency trading firms by Atlas ATS in New York and Hong Kong and one from London-based Coinfloor, claiming to be the first auditable bitcoin exchange, and a SecondMarket project of an exchange for institutional investors.[82]

A US government auction of almost 30,000 bitcoins seized in October 2013 from the Silk Road on 30 June 2014 by the US Marshals Service was said to increase legitimacy of the currency. The 45 registered bidders, each of whom put down a deposit of $200,000 made 63 bids.[133]

Bitcoins have been evaluated and treated in various ways around the world.[6] Magistrate Judge Amos Maazant of a Texas court classified bitcoins as currency.[134] A German court found bitcoin to be a unit of account.[6] The Finnish Government judged it to be a commodity.[135] The People's Bank of China has stated that bitcoin "is fundamentally not a currency".[81]

A WSJ journalist declared bitcoins a commodity in December 2013.[136] A Forbes journalist referred to bitcoins as digital collectible.[137] Two University of Amsterdam computer scientists proposed the term 'money-like informational commodity' in order "to allow for a systematic discussion of its development through all stages including an initial stage and a possible demise without being constrained by the implications of it being a money or a near-money".[138]

Wired magazine summarized the reception of bitcoin, saying "many leading economists [believe] bitcoin is a fatally flawed idea shaped by people who don’t really understand how money works".[139]

Few governments have moved to regulate bitcoin and similar private currencies. According to the European Central Bank, traditional financial sector regulation is not applicable because bitcoin does not involve traditional financial actors.[140] Under other regimes, existing rules have been extended to include bitcoin and bitcoin companies. Steven Strauss, a Harvard public policy professor, suggested in April 2013 governments could outlaw bitcoin,[141] a possibility that was mentioned in a 2013 SEC filing made by a bitcoin investment vehicle.[142] A detailed survey of forty foreign jurisdictions and the European Union is maintained by the US Library of Congress.[143]

Bolivia

Bitcoin is banned by the Bolivian central bank.[144]

Canada

The Canadian government announced in February 2014 that it was going to regulate bitcoin under existing anti-money laundering and counter-terrorist financing legislation.[145] In Quebec, The Financial Markets Authority stated in regards to bitcoin ATMs, that it would prosecute any violation of the Securities Act, the Derivatives Act, or the Money Services Business Act.[146]

China

China restricted bitcoin exchange for local currency in December 2013.[64] On 10 April 2014 the People’s Bank of China ordered banks and all third-party payment services to stop dealing with anyone in the bitcoin business. The ruling de-funds all Chinese bitcoin trading websites, as they will no longer have bank accounts in China.[147]

Cyprus

The use of bitcoins is not regulated in Cyprus.[148] On 11 December 2013, the Central Bank of Cyprus issued a statement on bitcoins, stating that "it considers the use of any kind of virtual money as particularly dangerous, given that it is not under any regulatory system and its operation is unchecked."[149]

Ecuador

On the 24th of July 2014, Ecuador effectively banned bitcoin, along with all other decentralized digital currencies, approving a monetary reform allowing the government to create its own centralized digital currency. This new reform comes as a severe blow to the bitcoin industry in Ecuador, since it demands that they shut down their operations immediately. Those who defy the ban will face prosecution, and all bitcoins circulated and assets in bitcoin trades face confiscation.[150]

Europe

In July 2014 the European Banking Authority advised European banks not to deal in virtual currencies such as bitcoin until a regulatory regime was in place.[151][152]

Hong Kong

Pre-existing Hong Kong law covers acts of fraud and money laundering involving virtual commodities.[153]

India

Digital or virtual currencies such as bitcoin have gained widespread acceptance in India despite a natural skepticism to assets not backed by tangible entities such as land. After the RBI warning in December 2013, a number of bitcoin operators shut shop.[citation needed] The actions of the ED (enforcement directorate) and the I-T (income-tax) department have sent tremors throughout the mainstream bitcoin community in India, if only for the reason that there is still no official regulation on how companies involved in dealing with digital currencies should comply with anti-money laundering and financial transaction laws.

Indonesia

A spokesman for Bank Indonesia reportedly issued a statement on bitcoin in December 2013, saying that "bitcoin is a potential payment method, but it’s different than ordinary currency... It is not regulated by the central bank so there are risks... At the moment, we’re studying bitcoin and we have no plan to issue a regulation on it."[148][154]

Japan

No laws in Japan regulate the use of bitcoins. Haruhiko Kuroda, governor of the Bank of Japan (BOJ), stated in December, 2013, that BOJ was "researching issues of bitcoins, but I have nothing to say regarding bitcoins at the moment."[155] As of July 2014, Japan’s new Bitcoin business advocacy group, The Japan Authority of Digital Asset, has launched with the government’s explicit support, aiming to help establish standards and codes of conduct for its member organizations.[156]

Jersey

The first regulated bitcoin fund was established in Jersey in July 2014, with the approval of the Jersey Financial Services Commission, after island leaders expressed a desire for Jersey to become a global center for digital currencies. At the time of the establishment of the fund, bitcoin was already being accepted by some local businesses.[105]

Russian Federation

On 27 January 2014, the Central Bank of the Russian Federation issued a statement entitled "On Using Virtual Currencies, Specifically Bitcoin, in Transactions." According to the statement, the Central Bank views the services of Russian legal entities aimed at assisting in the exchange of bitcoins for goods, services, or currencies as a "dubious activity" associated with money laundering and terrorism financing, and recommends that Russian individuals and legal entities refrain from transactions involving bitcoins.[157]

Singapore

The Monetary Authority of Singapore may require bitcoin intermediaries to collect personal details of their customers and report suspicious activity similar to what it requires from money changers.[158]

USA

In the US the first step of regulation occurred in July 2011, when the US Department of Treasury's Financial Crimes Enforcement Network added "other value that substitutes for currency" to its definition of Money services businesses.[159] In 2013 the Treasury issued new rules regarding virtual currencies,[160] whereby exchanges (but not users) are considered money transmitters and must comply with rules to prevent money laundering and terrorist financing.[161] Besides obtaining personal details of clients, bitcoin exchanges must verify that their customers are not on the Office of Foreign Asset Control’s Specially Designated Nationals list.[162] In April 2014, the Treasury confirmed that bitcoin cloud mining[163] and escrow services[164] are not classified as money transmitters.[165]

The US Government Accountability Office reviewed virtual currencies upon the request of the Senate Finance Committee and in May 2013 recommended[166] that the IRS formulate tax guidance for bitcoin businesses. On 25 March 2014, in time for 2013 tax filing, the IRS issued a guidance that virtual currency is treated as property for US federal tax purposes and that "an individual who 'mines' virtual currency as a trade or business [is] subject to self-employment tax."[167]

The US Commodity Futures Trading Commission stated in March 2014 it was considering regulation of digital currencies.[168]

In January 2014, the US Securities and Exchange Commission (SEC) was “very focused” on whether bitcoin-denominated stock exchanges were illegal, per its enforcement administrator, and inquired into the gambling site SatoshiDice listing shares on bitcoin exchange MPEx.[169] In May it warned investors that "both fraudsters and promoters of high-risk investment schemes may target Bitcoin users."[170] The SEC charged and settled with the former owner of SatoshiDice in June 2014 for selling securities without registering with the SEC.[171]

The IRS classified bitcoins as a capital asset end of March 2014[172] and subject to taxes on capital gains.[173]

On 8 May 2014, the US Federal Election Commission issued draft guidance to US politicians who want to receive bitcoin donations.[174] The Commission declined to declare bitcoins currency, opting to deem them items "of value."[175]

In May 2014, Brett Stapper, co-founder of Falcon Global Capital, registered to lobby members of Congress and federal agencies on issues related to bitcoin.[176]

As of July 2014, there are no rules at the US state level yet; In March, the New York State Department of Financial Services had officially invited bitcoin exchanges to apply with them.[177] On 17 July it published draft regulations for businesses that receive, exchange, transmit or store virtual currency.[178] Businesses would have to provide transaction receipts, disclosures about risks, policies to handle customer complaints, maintain a cybersecurity program, hire a compliance officer and verify details about their customers to follow anti-money-laundering rules, per FinCEN.[178]

California Assemblyman Roger Dickinson (D-Sacramento) drafted legislation (Assembly Bill 129)drafted legislation (Assembly Bill 129) to legalize bitcoin and all other alternative and digital currency, such as Litecoin, Dogecoin, Starbucks Stars, and Amazon Coins.[179] However, Dickinson "thinks the federal government should regulate the cryptocurrency" and said "I saw this legislation as a ways of cleaning up the code in California to conform to reality".[179]

International guidance

The 2013 G7's Financial Action Task Force published guidance for Internet-based payment services that defines "exchangers buying or selling digital currency for cash (or other digital currencies) [...] as a virtual bureau de change" and warns that "Internet-based payment services that allow third party funding from anonymous sources may face an increased risk of [money laundering/terrorist financing]" concluding that this may "pose challenges to countries in [anti-money laundering/counter terrorist financing] regulation and supervision."[180]

Criminal activity

Bitcoins have been associated with online criminal behavior and so-called cybercriminals.[181] Used to obfuscate online transactions, bitcoins are seized when deep web black markets are shut by authorities.[182] Criminal activities have stigmatized the currency and attracted the attention of financial regulators, legislative bodies, and law enforcement.[183] CNN has referred to bitcoin as a "shady online currency [that is] starting to gain legitimacy in certain parts of the world,"[184] and The Washington Post calls it "the currency of choice for seedy online activities."[185] The FBI stated in a 2012 report that "bitcoin will likely continue to attract cyber-criminals who view it as a means to move or steal funds."[181] Criminal activity involving bitcoin has largely centered around theft, money laundering, the use of botnets for mining, and the use of bitcoins in exchange for illegal items or services. "Like cash, it can be used for ill as well as for good."[11] Certain nation states may feel that its use in circumventing capital controls is also undesirable.[21] Despite claims made by non-profit Bitcoin Foundation that "cryptography is the reason no one can steal bitcoins," theft is widespread.[186]

Black markets

In 2012, it was estimated that 4.5% to 9% of all transactions of all bitcoin exchanges in the world were for drug trades on a single deep web drugs market, Silk Road.[187] The bulk of bitcoin purchases during the time were speculative in nature,[187] so drugs must have constituted a greater percentage of the actual goods purchased with bitcoins c. 2012. Silk Road was shut by US law enforcement in October 2013 leading to a short-term fall in the value of bitcoin.[188] Alternative sites were soon available, and in early 2014 the Australian Broadcasting Corporation reported that the closure of the Silk Road had little impact on the number of Australians selling drugs online, which had actually increased.[189]

Several news outlets have asserted that the popularity of bitcoins hinges on the ability to use them to purchase illegal goods.[190] Non-drug transactions were thought to be far less than the number involved in the purchase of drugs,[191] and roughly one half of all transactions made using bitcoin c. 2013 were bets placed at a single online gambling website, Satoshi Dice.[192] One source stated online gun dealers use bitcoin to sell arms without background checks.[193] The bitcoin community branded one site, Sheep Marketplace, as a scam when it prevented withdrawals and shut down after an alleged bitcoins theft.[194] In a separate case, escrow accounts with bitcoins belonging to patrons of a different black market were hacked in early 2014.[195]

Money laundering

Bitcoins may not be ideal for money laundering because all transactions are public.[196] Authorities have expressed concerns, however. The European Banking Authority and the FBI have both stated that bitcoin may be used for money laundering.[197] In early 2014, an operator of a US bitcoin exchange was arrested for money laundering.[72]

Ponzi scheme

Various journalists, US economist Nouriel Roubini, and the head of the Estonian central bank have voiced concerns that bitcoin may be a Ponzi scheme.[198] Bitcoin supporters disagree.[199] A 2012 report by the European Central Bank states, "it [is not] easy to assess whether or not the bitcoin system actually works like a pyramid or Ponzi scheme."[200]

In an alleged Ponzi scheme 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.[201] The SEC charged the company and its founder in 2013 "with defrauding investors in a Ponzi scheme involving bitcoin...".[201]

Thefts

A theft is an unauthorized transfer from a bitcoin address using the private key to unlock the address.[202] Because transactions are irreversible and the identity of users difficult to unmask, it is rare that stolen bitcoins are recovered and returned. Theft occurs on a regular basis despite claims made by the Bitcoin Foundation that theft is impossible.[186] Generating and storing keys offline mitigates the risk of theft. Most large-scale thefts occur at exchanges or online wallet services that store the private keys of many users. The thief hacks an online wallet service by finding a bug in its website or spreading malware to computers holding the private keys.[203]

Many high-profile thefts have been reported. In late November 2013, an estimated $100 million in bitcoins were stolen from the online illicit goods marketplace Sheep Marketplace, which immediately closed.[204] Users tracked the coins as they were processed and converted to cash, but no funds were recovered and no culprits identified.[204] 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.[195] In late February 2014 Mt. Gox, one of the largest virtual currency exchanges, filed for bankruptcy in Tokyo after its computer system was hacked and approximately $477 million in bitcoins were stolen. Flexcoin, a bitcoin storage specialist based in Alberta, Canada, shut down on March 2014 after saying it discovered a theft of about $650,000 in bitcoins.[205] Poloniex, a digital currency exchange, reported on March 2014 that it lost bitcoins valued at around $50,000.[206]

Malware

Bitcoin-related malware includes software that steals bitcoins from users using a variety of techniques, software that uses infected computers to mine bitcoins, and different types of ransomware, which disable computers or prevent files from being accessed until some payment is made. Security company Dell SecureWorks said in February 2014 that it had identified 146 types of bitcoin malware; about half of it undetectable with standard antivirus scanners.[207]

Unauthorized mining

In June 2011, Symantec warned about the possibility that botnets could mine covertly for bitcoins.[208] Malware used the parallel processing capabilities of GPUs built into many modern video cards.[209] 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.[210]

Several reports of employees or students using university or research computers to mine bitcoins have been published.[211][212]

Botnet cases

In mid-August 2011, bitcoin mining botnets were detected,[213] and less than three months later, bitcoin mining trojans had infected Mac OS X.[214]

In April 2013, electronic sports 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.[215]

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.[216]

For four days in December 2013 and January 2014, Yahoo Europe hosted an ad containing bitcoin mining malware that infected an estimated two million computers.[210] The software, called Sefnit, was first detected in mid-2013 and has been bundled with many software packages. Microsoft has been removing the malware through its Microsoft Security Essentials and other security software since January 2014.[217]

Malware stealing bitcoins

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.[207] Many of these also log keystrokes to record passwords, often avoiding the need to crack the keys.[207] A different approach detects when a bitcoin address is copied to a clipboard and quickly replaces it with a different address, tricking people into sending bitcoins to the wrong address.[207] This method is effective because bitcoin transactions are irreversible.

Cases of theft

One virus, spread through the Pony botnet, was reported in February 2014 to have stolen up to $220,000 in cryptocurrencies including 335 bitcoins from 85 wallets.[218] Security company Trustwave, which tracked the malware, reports that its latest version was able to steal 30 types of digital currency.[219]

A type 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.[220] A different trojan for Mac OS X, called CoinThief was reported in February 2014 to be responsible for multiple bitcoin thefts, including one user who lost 20 bitcoins.[220] The software was hidden in versions of some cryptocurrency apps on Download.com and MacUpdate.[220]

Ransomware

Another type of bitcoin-related malware is ransomware. One program called Cryptolocker, 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.[221] Police in Massachusetts 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.[222] 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.[221]

Security

There are two main ways the blockchain ledger can be corrupted to steal bitcoins: by fraudulently adding to or modifying it. The bitcoin system protects the blockchain against both using a combination of digital signatures and cryptographic hashes.[223]

The Addition Attack and digital signatures

Payers and payees are identified in the blockchain by their public cryptographic keys: most bitcoin transfers are from one public key to a different public key. (Actually, hashes of these keys are used in the blockchain, and are called "bitcoin addresses".) In principle, an attacker Eve could steal money from Alice and Bob by simply adding transactions to the blockchain ledger like Alice pays Eve 100 bitcoins, Bob pays Eve 100 bitcoins, and so on, using of course these people's bitcoin addresses instead of their names. The bitcoin protocol prevents this kind of theft by requiring every transfer to be digitally signed with the payer's private key; only signed transfers can be added to the blockchain ledger. Since Eve cannot forge Alice's signature, Eve cannot defraud Alice by adding an entry to the blockchain equivalent to Alice pays Eve 100 bitcoins. At the same time, anyone can verify Alice's signature using her public key, and therefore that she has authorized any transaction in the blockchain where she is the payer.[23]

The Modification Attack and mining

The other principal way to steal bitcoins would be to modify blockchain ledger entries. Eve could buy something from Alice, like a sofa, by adding a signed entry to the blockchain ledger equivalent to Eve pays Alice 100 bitcoins. Later, after receiving the sofa, Eve could modify that blockchain ledger entry to read instead: Eve pays Alice 1 bitcoin, or even delete the entry. Digital signatures cannot prevent this attack: Eve can simply sign her entry again after modifying it.

To prevent modification attacks, the bitcoin system first requires entries be added to the blockchain not one at a time, but in groups or blocks. More importantly, each block must be accompanied by a cryptographic hash of three things: the hash of the previous block, the block itself, and a number called a nonce. A hash of only the first two items will, like any cryptographic hash, always have a fixed number of bits (e.g. 256 for SHA-256). The nonce is a number which, when included, yields a hash with a specified number of leading zero bits. Because cryptographic hashes are essentially random, in the sense that their output cannot be predicted from their inputs, there is only one known way to find the nonce: to try out integers one after the other, e.g. 1, then 2, then 3, and so on. This process is called mining. The larger the number of leading zeros, the longer on average it will take to find a requisite nonce. The bitcoin system constantly adjusts the number of leading zeros so that the average time to find a nonce is about ten minutes. That way, as computer hardware gets faster over the years, the bitcoin protocol will simply require more leading zero bits to make mining always last about ten minutes.[23]

This system prevents modification attacks in part because an attacker has to recalculate all the hashes of the blocks after the modified one. In the example above, if Eve wants to change 100 bitcoins to 1 bitcoin, she will not only have to recompute the hash of the block that transaction is in, but of all the blocks that come after it; she will have to recreate the chain of blocks. Although she could do this in principle, it would take her about ten minutes on average per block. Concurrently, the network will continue to add blocks at a much faster rate than Eve alone can mine. Eve would have to recalculate all the blocks before the network could add a new one, or at least catch up with or overtake the network's miners. To achieve this would require roughly as much computing power as all existing bitcoin miners combined which would be prohibitively expensive and, if the bitcoin network is large enough, essentially unfeasible. Moreover, due to the financial incentives of mining new bitcoins, it would make more economic sense for Eve to devote her resources to normal bitcoin mining instead. Thus the system protects against fraudulent blockchain modifications by making them expensive and, if the attacker is rational, unappealing because they make less financial sense than becoming a miner. The more miners there are, the more expensive and less feasible such attacks become, making the whole system even more secure.[23]

Double-spending

Bitcoin system is based on an innovative solution of a problem common to all digital currency and payment schemes: that of so-called double-spending. With paper money or physical coins, when the payer transfers money to the payee, the payer cannot keep a copy of that dollar bill or coin. With digital money, which is just a computer file, this is not the case, and the payer could in principle spend the same money again and again, copying the file over and over. With bitcoin, when Eve offers to pay Alice some bitcoins, Alice can always first check the blockchain ledger to verify that Eve actually owns that many bitcoins. Of course, Eve could try to pay many people simultaneously; but bitcoin can defend against that. If Eve offers to pay Alice some bitcoins in exchange for goods, Alice can stipulate that she will not deliver the goods until Eve's payment to Alice appears in the blockchain, which typically involves waiting about ten minutes.[224]

Types of attacks

Race attack

If the transaction has no confirmations, shops and services which accept payment can be exposed to a so-called race attack. For example, two transactions are created for the same funds to be sent to different shops/services. System rules ensure that only one of those transactions can be added to the block chain.[11]

Shops can take numerous precautions to reduce this type of attack. It is always good to consider whether you should accept transactions without any confirmation.

Finney attack

Shops or services which accept transactions without any confirmation are affected. A Finney attack is an attack which requires the participation of a miner to premine a block sending the money to be defrauded back to the fraudster. The risk of such an attack cannot be reduced to nothing regardless of the preventative measures taken by shops or services, but it does require the participation of a miner and an ideal combination of contributing factors. It is no mean feat, the miner risks a potential loss of the block reward. Just as with the other type of attack, the shop or service must seriously consider its policies concerning transactions without any confirmation.[citation needed]

Vector76 attack

Also called an attack with confirmation, this is a combination of the 2 aforementioned attacks which gives the perpetrator the ability to spend funds twice simply with a confirmation.[citation needed]

Brute force attack

This attack is possible even if the shop or service is expecting several transaction confirmations. It requires the attacker to be in possession of relatively high-performance hardware (hash frequency).

The perpetrator sends a transaction to the shop paying for a product/service and at the same time continues looking for a connection in the block chain (block chain fork) which recognizes this transaction. After a certain number of confirmations, the shop sends the product. If the perpetrator has found more than n blocks at this point, he breaks his block chain fork and regains his money, but if the perpetrator has not succeeded in doing this, the attack can be deemed a failure and the funds are sent to the shop, as should be the case.

The success of this attack depends on the speed (hash frequency) of the attacker and the number of confirmations for the shop/service. For example, if the attacker possesses 10% of the calculation power of the bitcoin network and the shop expects 6 confirmations for a successful transaction, the probability of success of such an attack will be 0.1%.[citation needed]

>50% attack

If the perpetrator controls more than 50% of the bitcoin network power, the probability of success of the aforementioned attack will be 100%. By virtue of the fact that the perpetrator can generate blocks more often than the other part of the network, he can create his own block chain until it becomes longer than the "integral" part of the network.[225]

In the media

A bitcoin documentary film called The Rise and Rise of Bitcoin made its debut at the Tribeca Film Festival in New York on 23 April 2014, chronicling bitcoin's origins to its explosive growth in 2013.[226]

In Fall 2014, undergraduate students at the Massachusetts Institute of Technology will receive $100 in bitcoins "to better understand this emerging technology". A student had the idea of a Bitcoin Club and raised more than half a million dollars from a high frequency trader.[227]

Some US political candidates, including New York City Democratic Congressional candidate Jeff Kurzon have said they would accept campaign donations in bitcoin.[228]

See also

Notes

  1. ^ It is not known whether the name "Satoshi Nakamoto" is real or a pseudonym, or whether it represents one person or a group of people.
  2. ^ There is no uniform convention for bitcoin capitalization. Some sources use Bitcoin, capitalized, to refer to the technology and network and bitcoin, lowercase, to refer to the unit of account.[7] The WSJ and The Chronicle of Higher Education advocate use of lowercase bitcoin in all cases, however.[8] This article follows the latter convention.

References

 This article incorporates text available under the CC BY-SA 3.0 license.

  1. ^ a b Jon Matonis (17 September 2013). "Bitcoin gaining market-based legitimacy as XBT". Coindesk. Retrieved 14 December 2013.
  2. ^ a b "Cracking the Bitcoin: Digging Into a $131M USD Virtual Currency". Daily Tech. 12 June 2011. Retrieved 30 September 2012. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  3. ^ Ron Dorit; Adi Shamir (2012). "Quantitative Analysis of the Full Bitcoin Transaction Graph" (PDF). Cryptology ePrint Archive. Retrieved 18 October 2012.
  4. ^ "Bitcoin: A Peer-to-Peer Electronic Cash System" (PDF). bitcoin.org. October 2008. Retrieved 28 April 2014.
  5. ^ Davis, Joshua. "The Crypto-Currency: Bitcoin and its mysterious inventor". The New Yorker.
  6. ^ a b c "Regulation of Bitcoin in Selected Jurisdictions" (PDF). The Law Library of Congress, Global Legal Research Center. January 2014. Retrieved 9 April 2014.
  7. ^ a b Bustillos, Maria (2 April 2013). "The Bitcoin Boom". The New Yorker. Condé Nast. Retrieved 22 December 2013. (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.)
  8. ^ For WSJ, see Vigna, Paul (3 March 2014). "BitBeat: Is It Bitcoin, or bitcoin? The Orthography of the Cryptography". WSJ. Retrieved 21 April 2014.
    • For Chronicle of Higher Ed, see Metcalf, Allan (14 April 2014). "The latest style". Lingua Franca blog. The Chronicle of Higher Education (chronicle.com). Retrieved 19 April 2014.
  9. ^ "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". fincen.gov. Financial Crimes Enforcement Network. 19 November 2013. Retrieved 1 June 2014.
  10. ^ a b Joyner, April (25 April 2014). "How bitcoin is moving money in Africa". usatoday.com. USA Today. Retrieved 25 May 2014.
  11. ^ a b c d e Jerry Brito and Andrea Castillo (2013). "Bitcoin: A Primer for Policymakers" (PDF). Mercatus Center. George Mason University. p. 5. Retrieved 22 October 2013.
  12. ^ "How do I get Bitcoins? (For Beginners)". The Bitcoin Bulletin. 11 March 2011. Retrieved 13 December 2013.
  13. ^ a b Joshua A. Kroll, Ian C. Davey, Edward W. Felten (11–12 June 2013). "The Economics of Bitcoin Mining, or Bitcoin in the Presence of Adversaries" (PDF). The Twelfth Workshop on the Economics of Information Security (WEIS 2013). Retrieved 8 May 2014. If the value paid out of a transaction (in Bitcoins) is less than the amount put in, the difference is treated as a transaction fee that can be collected by whoever manages to mine a block containing that transaction. A transaction fee is like a tip or gratuity left for the miner. {{cite web}}: line feed character in |quote= at position 233 (help)CS1 maint: multiple names: authors list (link)
  14. ^ "BitPay Passes 10,000 Bitcoin-Accepting Merchants On Its Payment Processing Network". Techcrunch. Techcrunch.com. 16 September 2013. Retrieved 21 October 2013.
  15. ^ Wingfield, Nick (30 October 2013). "Bitcoin Pursues the Mainstream". The New York Times. Retrieved 4 November 2013.
  16. ^ "Warning to consumers on virtual currencies" (PDF). 1 EBA/WRG/2013/01. European Banking Authority. 12 December 2013. pp. 1–3. Retrieved 18 April 2014.
  17. ^ For theft, see Nathaniel Popper (5 December 2013). "In the Murky World of Bitcoin, Fraud Is Quicker Than the Law". The New York Times. Retrieved 12 December 2013. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
    • For lack of chargebacks, see Jerry Brito and Andrea Castillo (2013). "Bitcoin: A Primer for Policymakers" (PDF). Mercatus Center. George Mason University. p. 12. Retrieved 22 October 2013.
  18. ^ a b c Grocer, Stephen (2 July 2013). "Beware the Risks of the Bitcoin: Winklevii Outline the Downside". Moneybeat. The Wall Street Journal. Retrieved 21 October 2013. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
  19. ^ Tracy, Ryan (5 November 2013). "Bitcoin Comes Under Senate Scrutiny". The Wall Street Journal.
  20. ^ Andy Greenberg (23 October 2013). "FBI Says It's Seized $28.5 Million In Bitcoins From Ross Ulbricht, Alleged Owner Of Silk Road" (blog). Forbes.com. Retrieved 24 November 2013.
  21. ^ a b Peterson, Andrea (27 January 2014). "This map shows which countries are friendly to Bitcoin". The Switch. The Washington Post. Retrieved 28 January 2014. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
  22. ^ a b Ramzan, Zulfikar (1 May 2013). "Bitcoin: Transaction block chains". khanacademy.org. Khan Academy. Retrieved 15 April 2014.
  23. ^ a b c d Ramzan, Zulfikar. "Bitcoin: What is it?". The Khan Academy. Retrieved 5 April 2014.
  24. ^ a b Ashlee Vance (14 November 2013). "2014 Outlook: Bitcoin Mining Chips, a High-Tech Arms Race". Businessweek. Retrieved 24 November 2013.
  25. ^ a b Ritchie S. King Sam Williams David Yanofsky (17 December 2013). "By reading this article, you're mining bitcoins". qz.com. Atlantic Media Co. Retrieved 17 December 2013.
  26. ^ "How much will the transaction fee be?". FAQ. Bitcoin Foundation. Retrieved 19 March 2014.
  27. ^ Rockman, Simon (17 January 2014). "Manic miners: Ten Bitcoin generating machines". The Register. Retrieved 13 February 2014.
  28. ^ a b Bays, Jason (9 April 2014). "Bitcoin offers speedy currency, poses high risks". Purdue Exponent. The Exponent Online. Retrieved 14 April 2014.
  29. ^ Mills, Kelly (3 April 2014). "Bitcoins lose viability". The Arbiter. Boise State Student Media. Retrieved 14 April 2014.
  30. ^ Simonite, Tom (5 September 2013). "Mapping the Bitcoin Economy Could Reveal Users' Identities". MIT Technology Review. Retrieved 2 April 2014.
  31. ^ Lee, Timothy (21 August 2013). "Five surprising facts about Bitcoin". washingtonpost.com. The Washington Post. Retrieved 2 April 2014.
  32. ^ For use of different address for each transaction, see McMillan, Robert (6 June 2013). "How Bitcoin lets you spy on careless companies". wired.co.uk. Conde Nast. Retrieved 2 April 2014.
  33. ^ Bar-El, Hagai (3 April 2014). "Bitcoin does not provide anonymity". hbarel.com.
  34. ^ For ATMs, see Jervis, Rick (20 February 2014). "Bitcoin ATMs come to USA". USA Today.
  35. ^ Steadman, Ian (26 April 2013). "Study: 45 percent of Bitcoin exchanges end up closing". Wired. Retrieved 28 April 2013. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  36. ^ Bustillos, Maria. "The Future of Bitcoin". The New Yorker. Retrieved 3 December 2013. {{cite web}}: Italic or bold markup not allowed in: |publisher= (help)
  37. ^ For wallets holding bitcoins, see Adam Serwer and Dana Liebelson (10 April 2013). "Bitcoin, Explained". motherjones.com. Mother Jones. Retrieved 26 April 2014.
  38. ^ a b Villasenor, John (26 April 2014). "Secure Bitcoin Storage: A Q&A With Three Bitcoin Company CEOs". forbes.com. Forbes. Retrieved 26 April 2014.
  39. ^ "Bitcoin: Bitcoin under pressure". The Economist. 30 November 2013. Retrieved 30 November 2013.
  40. ^ Staff, Verge (13 December 2013). "Casascius, maker of shiny physical bitcoins, shut down by Treasury Department". The Verge. Retrieved 10 January 2014.
  41. ^ Daniel Cawrey (@danielcawrey) (20 December 2013). "Canadian Man Builds World's First Wooden Bitcoin Wallet". Coindesk.com. Retrieved 10 January 2014.
  42. ^ a b c Skudnov, Rostislav (2012). Bitcoin Clients (PDF) (Bachelor's Thesis). Turku University of Applied Sciences. Retrieved 16 January 2014.
  43. ^ http://www.coindesk.com/bitcoin-version-0-9-0-brings-transaction-malleability-fixes-branding-change/.
  44. ^ Moore, Tyler and Nicolas Christin (April 2013). "Beware the Middleman: Empirical Analysis of Bitcoin-Exchange Risk. In Proceedings of the 17th International Conference on Financial Cryptography and Data Security (FC'13)" (PDF). {{cite journal}}: Cite journal requires |journal= (help)
  45. ^ Rubens, Paul (17 December 2013). "BBC News - Cybercrime shopping list study points to falling prices". Bbc.co.uk. Retrieved 17 December 2013.
  46. ^ Danny Bradbury (27 December 2013). "5 things to do with those Christmas bitcoins". Coindesk.com. Retrieved 14 January 2014.
  47. ^ "Man Throws Away 7,500 Bitcoins, Now Worth $7.5 Million". CBS DC. 29 November 2013. Retrieved 23 January 2014.
  48. ^ Thompson, Jennifer (21 March 2014). "Mt Gox finds 200,000 'lost' Bitcoins in old wallet". Financial Times. Retrieved 23 March 2014.
  49. ^ a b Buterin, Vitalik (12 March 2013). "Bitcoin Network Shaken by Blockchain Fork". Bitcoin Magazine. Retrieved 17 January 2014.
  50. ^ Skelton, Andy (15 November 2012). "Pay Another Way: Bitcoin". WordPress. Retrieved 24 April 2014.
  51. ^ Franceschi-Bicchierai, Lorenzo (18 April 2013). "OKCupid Now Accepts Bitcoin". Mashable. Retrieved 24 April 2014.
  52. ^ "Atomic Mall adds Bitcoin payments for approved merchants". powersellersunite.com. 17 November 2013. Retrieved 8 April 2014.
  53. ^ a b Dahlberg, Nancy (23 January 2014). "TigerDirect.com to accept Bitcoin". Miami Herald Business. Miami Herald. Retrieved 26 January 2014.
  54. ^ a b Vaishampayan, Saumya (9 January 2014). "Bitcoin now accepted on Overstock.com through VC-backed Coinbase". marketwatch.com. Wall Street Journal. Retrieved 10 February 2014.
  55. ^ Biggs, John (11 June 2014). "Expedia Now Accepts Bitcoin For Your Crypto-Vacations". Techcrunch. Retrieved 12 June 2014.
  56. ^ Jeremy Kirk (19 May 2013). "Electronic Frontier Foundation again takes bitcoin donations". PCWorld. Retrieved 25 January 2014.
  57. ^ For 2011 stoppage, see Cohn, Cindy (20 June 2011). "EFF and Bitcoin". Electronic Frontier Foundation. Retrieved 16 April 2014.
  58. ^ Dillet, Romain (16 May 2013). "Feds Seize Assets From Mt. Gox's Dwolla Account, Accuse It Of Violating Money Transfer Regulations". TechCrunch. Retrieved 15 May 2013.
  59. ^ Farrell, Greg (3 October 2013). "FBI Snags Silk Road Boss With Own Methods". Bloomberg. New York. Retrieved 27 October 2013.
  60. ^ Kapur, Saranya (15 October 2013). "China's Google Is Now Accepting Bitcoin". businessinsider.com. Business Insider, Inc. Retrieved 26 December 2013.
  61. ^ "As Chinese Investors Pile Into Bitcoin, China's Oldest Exchange, BTC China, Raises $5M From Lightspeed". TechCrunch. Retrieved 10 January 2014.
  62. ^ "BBC News - 'Legitimate' Bitcoin's value soars after Senate hearing". Bbc.co.uk. 19 November 2013. Retrieved 10 January 2014.
  63. ^ Lee, Cyrus (22 November 2013). "China no plans yet to legalize use of Bitcoins". ZDNet. Retrieved 27 November 2013.
  64. ^ a b Kelion, Leo (18 December 2013). "Bitcoin sinks after China restricts yuan exchanges". bbc.com. BBC. Retrieved 20 December 2013.
  65. ^ "China bans banks from bitcoin transactions". The Sydney Morning Herald. 6 December 2013.
  66. ^ "Baidu Stops Accepting Bitcoins After China Ban". Bloomberg. New York. 7 December 2013. Retrieved 11 December 2013.
  67. ^ "China bars use of virtual money for trading in real goods". English.mofcom.gov.cn. 29 June 2009. Retrieved 10 January 2014.
  68. ^ McMillan, Robert (29 October 2013). "Take a tour of Robocoin, the world's first Bitcoin ATM". Wired.
  69. ^ Raskin, Max (18 November 2013). "U.S. Agencies to Say Bitcoins Offer Legitimate Benefits". Bloomberg. Retrieved 24 November 2013.
  70. ^ By Todd Wasserman2013-11-18 14:06:30 UTC (18 November 2013). "Bitcoin Tops $600, Up 60x Over the Last Year". Mashable.com. Retrieved 10 January 2014.{{cite web}}: CS1 maint: numeric names: authors list (link)
  71. ^ "Bitcoin Set to Boom in Latin America". Blog.panampost.com. 2 January 2014. Retrieved 7 January 2014.
  72. ^ a b Lee, Dave (27 January 2014). "US makes Bitcoin exchange arrests after Silk Road closure". bbc.co.uk. BBC. Retrieved 28 January 2014.
  73. ^ For Mt. Gox being a large exchange, see "MtGox gives bankruptcy details". bbc.com. BBC. 4 March 2014. Retrieved 13 March 2014.
  74. ^ "MtGox bitcoin exchange files for bankruptcy". bbc.com. BBC. 28 February 2014. Retrieved 18 April 2014.
  75. ^ For Magic: The Gathering, see Vigna, Paul (25 February 2014). "Five Things About Mt. Gox's Crisis". The Wall Street Journal. Dow Jones and Company. Retrieved 18 April 2014.
  76. ^ Murphy, Kate (31 July 2013). "Virtual Currency Gains Ground in Actual World". The New York Times. Retrieved 6 May 2014. A type of digital cash, bitcoins were invented in 2009 and can be sent directly to anyone, anywhere in the world.
  77. ^ Carter, Stephen L. (29 November 2013). "Building Better Bitcoins". Bloomberg View. Bloomberg LP. Retrieved 25 May 2014. 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.
  78. ^ a b c d "Free Exchange. Money from nothing. Chronic deflation may keep Bitcoin from displacing its rivals". The Economist. 15 March 2014. Retrieved 25 March 2014.
  79. ^ Joon Ian Wong (28 November 2013). "CoinMap: Bitcoin-Accepting Merchants Increased 81% in November". CoinDesk. Retrieved 1 December 2013.
  80. ^ To obtain 35,000 figure, 16,000 merchants signed up with Bitcoin payment processor Coinbase are added to 20,000 merchants signed to BitPay.
  81. ^ a b "China's Bitcoin Exchanges Say Banks Will Close Their Accounts". Bloomberg. 10 April 2014. Retrieved 11 April 2014. 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.
  82. ^ a b c d Michael J. Casey (30 April 2014). "Bloomberg to List Bitcoin Prices, Offering Key Stamp of Approval". WSJ. Retrieved 1 May 2014.
  83. ^ Williams, Mark T (5 December 2013). "Beware Of Bitcoin". Cognoscenti blog. 90.9 WBUR Boston's NPR news station. Retrieved 15 April 2014.
  84. ^ Wilkes, Tommy (11 April 2013). "Backer defends virtual currency Bitcoin after big fall". Reuters. Retrieved 7 January 2014.
  85. ^ Lee, Timothy B. (4 November 2013). "Bitcoin Doesn't Have a Deflation Problem". Forbes. Retrieved 27 January 2014.
  86. ^ Roose, Kevin. "How Bitcoin Can Go Mainstream, in One Easy Step - Daily Intelligencer". Nymag.com. Retrieved 25 November 2013.
  87. ^ Colombo, Jesse (19 December 2013). "Bitcoin May Be Following This Classic Bubble Stages Chart". Forbes. Retrieved 7 January 2014.
  88. ^ Lee, Timothy (5 November 2013). "When will the people who called Bitcoin a bubble admit they were wrong". The Washington Post. Retrieved 10 January 2014.
  89. ^ Liu, Alec (19 March 2013). "When Governments Take Your Money, Bitcoin Looks Really Good | Motherboard". Motherboard.vice.com. Retrieved 7 January 2014.
  90. ^ Lee, Timothy B. (11 April 2013). "An Illustrated History Of Bitcoin Crashes". Forbes. Retrieved 7 January 2014.
  91. ^ "Bitcoin price charts". Bitcoincharts.com.
  92. ^ "Bitcoins gain traction in Argentina". {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help).Blogs.ft.com (16 April 2013). Retrieved 20 April 2013.
  93. ^ Lee, Timothy B. (19 August 2013). "Five surprising facts about Bitcoin". Washington Post blog. Archived from the original on 22 August 2013.
  94. ^ Salyer, Kirsten (21 March 2013). "Fleeing the Euro for Bitcoins". Bloomberg L.P. {{cite news}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  95. ^ Kearns, Jeff (4 December 2013). "Greenspan Says Bitcoin a Bubble Without Intrinsic Currency Value". bloomberg.com. Bloomberg LP. Retrieved 23 December 2013.
  96. ^ a b c Quiggin, John (16 April 2013). "The Bitcoin Bubble and a Bad Hypothesis". The National Interest. {{cite news}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  97. ^ For Andresen, see "Bitcoin's History of Crushing Speculators". The Motley Fool. 4 April 2013. Retrieved 7 January 2014.
    • For Hearn, see Barford, Vanessa (13 December 2013). "Bitcoin: Price v hype". bbc.com. BBC. Retrieved 23 December 2013.
  98. ^ Shiller, Robert (1 March 2014). "In Search of a Stable Electronic Currency". New York Times. {{cite news}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  99. ^ Boesler, Matthew (7 March 2013). "ANALYST: The Rise Of Bitcoin Teaches A Tremendous Lesson About Global Economics". Business Insider. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  100. ^ Gustke, Constance (23 November 2011). "The Pros And Cons Of Biting on Bitcoins". CNBC. Retrieved 4 December 2012. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  101. ^ Jonathan Stempel date=11 March 2014 (11 March 2014). "Beware Bitcoin: U.S. brokerage regulator". reuters.com. Retrieved 14 March 2014. {{cite news}}: Missing pipe in: |author= (help)CS1 maint: numeric names: authors list (link)
  102. ^ "Warning to consumers on virtual currencies". European Banking Authority. 12 December 2013. Archived from the original (PDF) on 28 December 2013. Retrieved 23 December 2013.
  103. ^ Popper, Nathaniel (18 November 2013). "Regulators See Value in Bitcoin, and Investors Hasten to Agree". New York Times. Retrieved 27 November 2013.
  104. ^ a b Simonite, Tom (12 June 2013). "Bitcoin Millionaires Become Investing Angels". Computing News. Retrieved 13 June 2013.
  105. ^ a b "Jersey approve Bitcoin fund launch on island". Big News Network.com. Retrieved 10 July 2014. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
  106. ^ "CoinSeed raises $7.5m, invests $5m in Bitcoin mining hardware – Investment Round Up". Red Herring. 24 January 2014. Retrieved 9 March 2014.
  107. ^ Sharf, Samantha (12 May 2013). "Bitcoin Gets Valued: Bank Of America Puts A Price Target On The Virtual Tender". Forbes. New York.
  108. ^ Schroeder, Stan (1 December 2013). "Cameron Winklevoss: Bitcoin Might Hit $40,000 Per Coin". Mashable. New York.
  109. ^ Williams, Mart (17 December 2013). "FINANCE PROFESSOR: Bitcoin Will Crash To $10 By Mid-2014". businessinsider.com. Business Insider. Retrieved 26 February 2014.
  110. ^ "Bitcoin Price". Retrieved 15 July 2014.
  111. ^ Doug Henwood (19 May 2014). "The Bitcoin Fantasy: Are Digital Currencies the Future of Money?". The Nation. pp. 12–17.
  112. ^ Michel Bauwens and Vasilis Kostakis (2014). "Four Future P2P Scenarios". Retrieved 30 June 2014.
  113. ^ a b Vasilis Kostakis and Chris Giotitsas (2014). "The (A)Political Economy of Bitcoin". TripleC: Communication, Capitalism & Critique, 12(2). p. 7. Retrieved 30 June 2014. Cite error: The named reference "3c" was defined multiple times with different content (see the help page).
  114. ^ a b Vasilis Kostakis and Michel Bauwens (2014 (in press)). "Network Society and Future Scenarios for a Collaborative Economy". Palgrave Macmillan. Retrieved 30 June 2014. {{cite web}}: Check date values in: |year= (help)CS1 maint: year (link)
  115. ^ Velde, François (December 2013). "Bitcoin: A primer". Chicago Fed letter. THE FEDERAL RESERVE BANK OF CHICAGO. p. 4. Retrieved December 2013. {{cite web}}: Check date values in: |accessdate= (help)
  116. ^ Paul Krugman (28 December 2013). "Bitcoin Is Evil". krugman.blogs.nytimes.com. Retrieved 28 December 2013.
  117. ^ Andolfatto, David (31 March 2014). "Bitcoin and Beyond: The Possibilities and Pitfalls of Virtual Currencies" (PDF). Dialogue with the Fed. Federal Reserve Bank of St. Louis. Retrieved 16 April 2014. Well-run central banks should welcome the emerging competition. There is (in my view) room for beneficial coexistence.
    • Wile, Rob (6 April 2014). "St. Louis Fed Economist: Bitcoin Could Be A Good Threat To Central Banks". businessinsider.com. Business Insider. Retrieved 16 April 2014.
    • Andolfatto, David (24 December 2013). "In gold we trust?". MacroMania. David Andolfatto. Retrieved 17 April 2014. 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.
  118. ^ Sparkes, Matthew (2 December 2013). "Software activist calls for 'truly anonymous' Bitcoins to 'protect democracy'". London: Telegraph. Retrieved 27 December 2013.
  119. ^ Shankland, Stephen (10 December 2013). "PayPal president David Marcus: Bitcoin is good, NFC is bad". CNET. Retrieved 10 December 2013.
  120. ^ Connell, Michael (30 December 2013). "How to use Bitcoin for Stand-up Comedy". Bitcoin Magazine. Retrieved 22 March 2014.
  121. ^ "Atomic Mall adds Bitcoin payments for approved merchants". powersellersunite.com. 17 November 2013. Retrieved 8 April 2014.
  122. ^ "Clearly Canadian Joins Bitcoin Community". finance.yahoo.com. Yahoo! Finance. 23 December 2013. Retrieved 10 February 2014.
  123. ^ Davidson, Kavitha (16 January 2014). "How Many Bitcoins for a Courtside Seat?". bloomberg.com. Bloomberg LP. Retrieved 20 January 2014.
  124. ^ Holpuch, Amanda (22 November 2013). "Virgin Galactic to accept Bitcoin for space flights". The Guardian. Retrieved 24 November 2013.
  125. ^ Kharif, Olga (6 January 2014). "Bitcoin Tops $1,000 Again as Zynga Accepts Virtual Money". bloomberg.com. Bloomberg LP. Retrieved 20 January 2014.
  126. ^ "Newegg accepts bitcoins". newegg.com. 2014-07-1. Retrieved 3 Jule 2014. {{cite web}}: Check date values in: |accessdate= and |date= (help)
  127. ^ "Expedia Starts Accepting Bitcoin for Hotel Bookings". Wall Street Journal. 11 June 2014. Retrieved 27 July 2014.
  128. ^ "Dell Begins Accepting Bitcoin". New York Times. 18 July 2014. Retrieved 18 July 2014.
  129. ^ Vigna, Paul (22 November 2013). "The University of Bitcoin Rises in Cyprus". The Wall Street Journal. Retrieved 22 November 2013.
  130. ^ a b Dougherty, Carter (5 December 2013). "Bankers Balking at Bitcoin in U.S. as Real-World Obstacles Mount". bloomberg.com. Bloomberg. Retrieved 16 April 2014.
  131. ^ Hill, Kashmir (5 December 2013). "Bitcoin Valued At $1300 By Bank of America Analysts". Forbes.com. Retrieved 23 March 2014.
  132. ^ "Bitcoin: is Circle the world's first crypto-currency bank?". The week.co.uk. 16 May 2014. Retrieved 13 June 2014.
  133. ^ The Guardian newspaper: Silk Road's legacy 30,000 bitcoin sold at auction to mystery buyers, 1 July 2014
  134. ^ Coldewey, Devin (8 August 2013). "'Bitcoin is a currency': Federal judge says the virtual cash is real money". NBC News. Retrieved 27 January 2014.
  135. ^ "Bitcoin Judged Commodity in Finland After Failing Money Test". Bloomberg. New York. 20 January 2014. Retrieved 27 January 2014.
  136. ^ Chapman, Lizette (12 December 2013). "Coinbase to Push Bitcoin From Commodity to Currency, With $25M From Investors". The Wall Street Journal. Retrieved 27 January 2014.
  137. ^ Woodhill, Louis (4 November 2013). "Bitcoins Are Digital Collectibles, Not Real Money". Forbes. Retrieved 27 January 2014.
  138. ^ Bergstra, J. A., Weijland, P. (February 2014). "Bitcoin: a money-like informational commodity" (PDF). arXiv.org. Cornell University. p. 26.{{cite web}}: CS1 maint: multiple names: authors list (link)
  139. ^ Metz, Cade (02.10.14). "Meet Patrick Byrne: Bitcoin Messiah, CEO of Overstock, Scourge of Wall Street". Wired. Wired. Retrieved 07.16.14. {{cite web}}: Check date values in: |accessdate= and |date= (help)
  140. ^ European Central Bank (October 2012). "1". Virtual Currency Schemes (PDF). Frankfurt am Main: European Central Bank. p. 5. ISBN 978-92-899-0862-7. Retrieved 5 March 2014.
  141. ^ Strauss, Steven (14 April 2013). "Nine Trust-Based Problems With Bitcoin". The Huffington Post. Retrieved 20 October 2013.
  142. ^ Grocer, Stephen (2 July 2013). "Beware the Risks of the Bitcoin: Winklevii Outline the Downside". Moneybeat. Retrieved 21 October 2013.
  143. ^ "Regulation of Bitcoin in Selected Jurisdictions". US Library of Congress. 21 April 2014. Retrieved 2 June 2014.
  144. ^ Bloomberg
  145. ^ Duhaime, Christine. "Canada to Regulate Bitcoin, Digital Currencies and online casinos under its anti-money laundering and counter-terrorist financing laws". Retrieved 7 March 2014. Duhaime Law
  146. ^ Duhaime, Christine. "1st Canadian official regulatory response to Bitcoin highlights Ponzi scheme and money laundering risks". Retrieved 7 March 2014. Duhaime Law
  147. ^ "China's banks give deadline for bitcoin exchanges to close their trading accounts". TechInAsia. 10 April 2014. Retrieved 9 May 2014. China's bitcoin exchanges are being issued with formal notices stating that their bank accounts must be closed by April 15. China's BTC Trade exchange announced today that it has been contacted by its bank and told to remove all funds prior to the deadline or else the assets will be frozen.
  148. ^ a b "Regulation of Bitcoin in Selected Jurisdictions". Retrieved 8 April 2014.
  149. ^ "Cyprus Central Bank warns about risks in use of Bitcoin". Retrieved 11 December 2013.
  150. ^ "Ecuador Bans Bitcoin, Initiates Government-Run Digital Currency". Pan Am Post. 25 July 2014.
  151. ^ "EBA Opinion on 'virtual currencies" (pdf). European Banking Authority. 4 July 2014. p. 46. Retrieved 8 July 2014.
  152. ^ "EU banking regulator warns against dealing with bitcoins sans rules". Big News Network.com. Retrieved 5 July 2014. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
  153. ^ Vallikappen, Sanat (13 March 2014). "Singapore to Regulate Bitcoin Operators for Laundering Risk". Bloomberg. Retrieved 23 March 2014.
  154. ^ "Bitcoin, Digital Currency and the Internet of Money" (PDF). Retrieved 8 May 2014.
  155. ^ Summary of Bank of Japan Press Conference, at 10
  156. ^ Money & Tech: Japan’s new Bitcoin business advocacy group, The Japan Authority of Digital Asset, has launched with the government’s explicit support, aiming to help establish standards and codes of conduct for its member organizations.
  157. ^ "Russia: Bitcoin Exchanges Can Be Penalized". The Library of Congress. 2 February 2014. Retrieved 23 March 2014.
  158. ^ "Singapore acts first to regulate Bitcoin". New Europe. 23 March 2014. Retrieved 23 March 2014.
  159. ^ Financial Crimes Enforcement Network (21 July 2011). "Financial Crimes Enforcement Network". Bank Secrecy Act Regulations; Definitions and Other Regulations Relating to Money Services Businesses. Federal register. p. 76 FR 43585. Retrieved 6 March 2014. 31 C.F.R. § 1010.100(ff)(5)(i)(A)
  160. ^ "FIN-2013-G001: Application of FinCEN's Regulations to Persons Administering, Exchanging, or Using Virtual Currencies". Financial Crimes Enforcement Network. 18 March 2013. p. 6. Retrieved 4 March 2014.
  161. ^ Lee, Timothy (20 March 2013). "US regulator Bitcoin Exchanges Must Comply With Money Laundering Laws". Arstechnica. Bitcoin miners must also register if they trade in their earnings for dollars. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  162. ^ "Specially Designated Nationals List (SDN)". Resource Center. US Treasury. 20 March 2014. Retrieved 24 March 2014.
  163. ^ "FIN-2014-R007: Application of Money Services Business regulations to the rental of computer systems for mining virtual currency". Financial Crimes Enforcement Network. 29 April 2014. Retrieved 10 May 2014.
  164. ^ "FIN-2014-R005: Whether a Company that Offers Secured Transaction Services to a Buyer and Seller in a Given Sale of Goods or Services is a Money Transmitter". Financial Crimes Enforcement Network. 29 April 2014. Retrieved 10 May 2014.
  165. ^ Andrew Moran (1 May 2014). "U.S. FinCEN confirms bitcoin escrow, cloud mining not money transmitters". CoinBuzz. Retrieved 10 May 2014. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  166. ^ US Government Accountability Office (May 2013). "Virtual Economies and currencies: Additional IRS guidance could reduce tax compliance risks". GAO Report GAO-13-516. Report to the Committee on Finance, U.S. Senate. Retrieved 6 March 2014.
  167. ^ IRS (25 March 2014). "IRS Virtual Currency Guidance" (PDF). Notice 2014-21. IRS. Retrieved 30 March 2014.
  168. ^ Miedema, Douwe (11 March 2014). "U.S. swaps watchdog says considering bitcoin regulation". Reuters.com. Retrieved 11 March 2014.
  169. ^ Dougherty, Carter (20 March 2014). "Gambling Website's Bitcoin-Denominated Stock Draws SEC Inquiry". Bloomberg BusinessWeek.com. Bloomberg LP. Retrieved 13 June 2014.
  170. ^ "Investor Alert: Bitcoin and Other Virtual Currency-Related Investments". Investor.gov. U.S. Securities and Exchange Commission. Retrieved 13 May 2014.
  171. ^ "Press Release SEC Charges Bitcoin Entrepreneur With Offering Unregistered Securities". SEC.gov. 3 June 2014. Retrieved 13 June 2014.
  172. ^ "IRS Says Bitcoin, Other Convertible Virtual Currency To Be Taxed Like Stock". Forbes. 25 March 2014. Retrieved 7 April 2014.
  173. ^ Schroeder, Peter (25 March 2014). "IRS moves to tax bitcoins". The Hill. Retrieved 27 May 2014.
  174. ^ Goodman, Lee E. (8 May 2014). "FEC Advisory Opinion 2014-02" (PDF). Federal Election Commission. Retrieved 8 May 2014.
  175. ^ Levinthal, Dave (8 May 2014). "What the FEC's Bitcoin ruling means". Center for Public Integrity. Retrieved 8 May 2014.
  176. ^ Hattem, Julian (23 May 2014). "Bitcoin gets a lobbyist". The Hill. Retrieved 27 May 2014.
  177. ^ "In the Matter of Virtual Currency Exchanges" (PDF). Public Order. New York State Department of Financial Services. 11 March 2014. Retrieved 30 March 2014.
  178. ^ a b Vigna, Paul (17 July 2014). "NY Financial Regulator Releases Draft of 'Bitlicense' for Bitcoin Businesses". WSJ. Dow Jones & Company. {{cite news}}: |access-date= requires |url= (help)
  179. ^ a b Cosco, Joey (25 June 2014). "Bitcoin Is Actually Illegal In California, But That Could Change Soon". Business Insider. Retrieved 26 June 2014.
  180. ^ "Guidance for a Risk-Based Approach: Prepaid Cards, Mobile Payments and Internet-based Payment Services" (PDF). Guidance for a risk-based approach. Paris: Financial Action Task Force (FATF). June 2013. p. 47. Retrieved 6 March 2014.
  181. ^ a b "Bitcoins Virtual Currency: Unique Features Present Challenges for Deterring Illicit Activity" (PDF). Cyber Intelligence Section and Criminal Intelligence Section. FBI. 24 April 2012. Retrieved 20 October 2013.
  182. ^ For obfuscation of transactions and seizure of bitcoins from black market Utopia, see Kelion, Leo (12 February 2014). "Five arrested in Utopia dark net marketplace crackdown". bbc.co.uk. BBC. Retrieved 13 February 2014.
  183. ^ For Bitcoin enthusiasts worries that the currency may be stigmatized as "drug barter tokens", see Chen, Adrian (1 June 2011). "The Underground Website Where You Can Buy Any Drug Imaginable". {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help). Gawker.
  184. ^ Sanati, Cyrus (18 December 2012). "Bitcoin looks primed for money laundering". money.cnn.com. CNN. Retrieved 18 October 2013.
  185. ^ Timothy B. Lee and Hayley Tsukayama (2 October 2013). "Authorities shut down Silk Road, the world's largest Bitcoin-based drug market". The Washington Post. Retrieved 21 October 2013.
  186. ^ a b For claim, see "Developing a More Open Economy". bitcoinfoundation.org. Bitcoin Foundation. Retrieved 4 March 2014. Cryptography is the key to Bitcoin's success. It's the reason that no one can double spend, counterfeit or steal Bitcoins.
    • For widespread theft, see "Bitcoin under pressure". economist.com. The Economist Newspaper Limited. 30 November 2013. Retrieved 4 March 2014. there have also been many cases of Bitcoin theft
  187. ^ a b Christin, Nicolas (2013). Traveling the Silk Road: A Measurement Analysis of a Large Anonymous Online Marketplace (PDF). Carnegie Mellon INI/CyLab. p. 8. Retrieved 22 October 2013. 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
  188. ^ For law enforcement action, see "Bitcoin price plummets after Silk Road closure". The Guardian. 3 October 2013. Digital currency loses quarter of value after arrest of Ross Ulbricht, who is accused of running online drugs marketplace
  189. ^ Katie Silver (31 March 2014). "Silk Road closure fails to dampen illegal drug sales online, experts say". ABC News.
  190. ^ "Monetarists Anonymous". The Economist. The Economist Newspaper Limited. 29 September 2012. Retrieved 21 October 2013.
  191. ^ Mardlin, John Jeffrey (2 October 2013). "How Will The FBI Shut Down Of Silk Road Affect Bitcoins?". Quora. Forbes. Retrieved 21 October 2013.
  192. ^ Geuss, Megan (24 August 2013). "Firm says online gambling accounts for almost half of all Bitcoin transactions". Ars Technica. Retrieved 21 October 2013.
  193. ^ Smith, Gerry (15 April 2013). "How Bitcoin Sales Of Guns Could Undermine New Rules". huffingtonpost.com. TheHuffingtonPost.com, Inc. Retrieved 20 October 2013.
  194. ^ Kaminska, Izabella (4 December 2013). "Capital controls, Bitcoin edition". FT Alphaville. Financial Times. Retrieved 28 January 2014.
  195. ^ a b "Silk Road 2 loses $2.7m in bitcoins in alleged hack". BBC News. 14 February 2014. Retrieved 15 February 2014.
  196. ^ Kirk, Jeremy (28 August 2013). "Bitcoin offers privacy-as long as you don't cash out or spend it". PC World.
  197. ^ For FBI, see "Bitcoins Virtual Currency: Unique Features Present Challenges for Deterring Illicit Activity" (PDF). Cyber Intelligence Section and Criminal Intelligence Section. FBI. 24 April 2012. Retrieved 20 October 2013.
  198. ^ For journalist, see Posner, Eric (11 April 2013). "Bitcoin is a Ponzi scheme—the Internet's favorite currency will collapse". Slate. Retrieved 1 April 2014.
  199. ^ Tucker, Jeffrey (1 December 2013). "Ponzi Logic: Debunking Gary North". The Libertarian Standard. Retrieved 12 February 2014.
  200. ^ "Virtual Currency Schemes" (PDF). European Central Bank. October 2012. Retrieved 4 December 2012. {{cite journal}}: Cite journal requires |journal= (help)
  201. ^ a b "SEC charges Texas man with running Bitcoin-denominated Ponzi scheme" (Press release). US Securities and Exchange Commission. 23 July 2013. Retrieved 7 March 2014.
  202. ^ Jeffries, Adrianne (19 December 2013). "How to steal Bitcoin in three easy steps". The Verge. Retrieved 17 January 2014.
  203. ^ Everett, David. "So how can you steal Bitcoins". Smartcard & Identity News. Retrieved 17 January 2014.
  204. ^ a b Hern, Alex (9 December 2013). "Recovering stolen bitcoin: a digital wild goose chase". The Guardian. Retrieved 6 March 2014.
  205. ^ Ligaya, Armina (5 March 2014). "After Alberta's Flexcoin, Mt. Gox hacked, Bitcoin businesses face sting of free-wheeling ways". Financial Post. Retrieved 7 March 2014.
  206. ^ Truong, Alice (6 March 2014). "Another Bitcoin exchange, another heist". Fast Company. Retrieved 7 March 2014.
  207. ^ a b c d Hajdarbegovic, Nermin (27 February 2014). "Nearly 150 strains of malware are after your bitcoins". CoinDesk. Retrieved 7 March 2014.
  208. ^ Peter Coogan (17 June 2011). "Bitcoin Botnet Mining". Symantec.com. Retrieved 24 January 2012. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  209. ^ Goodin, Dan (16 August 2011). "Malware mints virtual currency using victim's GPU". The Register. Retrieved 10 January 201. {{cite news}}: Check date values in: |accessdate= (help)
  210. ^ a b Hajdarbegovic, Nermin (8 January 2014). "Yahoo infects 2 million European PCs with Bitcoin malware". CoinDesk. Retrieved 7 March 2014.
  211. ^ Zagaeski, Sid (23 April 2014). "Iowa State University Computers Hacked to Get Bitcoin Mining Power". Coin Report.net. Coin Report. Retrieved 13 June 2014.
  212. ^ Hornyack, Tim (6 June 2014). "US researcher banned for mining Bitcoin using university supercomputers". PC world.com. IDG Consumer & SMB. Retrieved 13 June 2014.
  213. ^ "Infosecurity - Researcher discovers distributed bitcoin cracking trojan malware". Infosecurity-magazine.com. 19 August 2011. Retrieved 24 January 2012.
  214. ^ "Mac OS X Trojan steals processing power to produce Bitcoins - sophos, security, malware, Intego - Vulnerabilities - Security". Techworld. 1 November 2011. Retrieved 24 January 2012.
  215. ^ "E-Sports Entertainment settles Bitcoin botnet allegations". BBC News. 20 November 2013. Retrieved 24 November 2013.
  216. ^ Hajdarbegovic, Nermin (5 December 2013). "German police detain 'Bitcoin mining hackers'". CoinDesk. Retrieved 7 March 2014.
  217. ^ Hajdarbegovic, Nermin (22 January 2014). "Microsoft destroys Bitcoin mining botnet Sefnit". CoinDesk. Retrieved 7 March 2014.
  218. ^ Rizzo, Pete (4 March 2014). "Bitcoin bank Flexcoin to close after $600,000 bitcoin theft". CoinDesk. Retrieved 7 March 2014.
  219. ^ Finkle, Jim (24 February 2014). "'Pony' botnet steals bitcoins, digital currencies: Trustwave". Reuters. Retrieved 7 March 2014.
  220. ^ a b c Southurst, Jon (10 February 2014). "'CoinThief' Mac malware steals bitcoins from your wallet". CoinDesk. Retrieved 7 March 2014.
  221. ^ a b "How Ransomware turns your computer into a bitcoin miner". The Guardian. 10 February 2014. Retrieved 7 March 2014.
  222. ^ Gibbs, Samuel (21 November 2013). "US police force pay bitcoin ransom in Cryptolocker malware scam". The Guardian. Retrieved 7 March 2014.
  223. ^ Bondi, Richard. "How Bitcoin Works: A guide for the digitally perplexed". Retrieved 5 April 2014.
  224. ^ Wallace, Benjamin (23 November 2011). "The Rise and Fall of Bitcoin". Wired. Retrieved 4 November 2013. One of the core challenges of designing a digital currency involves something called the double-spending problem.
  225. ^ Paul Vigna and Michael J. Casey. (16 June 2014). "Short-Term Fixes To Avert "51% Attack"". Money Beat. WSJ.com. Retrieved 30 June 2014.
  226. ^ http://newsbtc.com/2014/03/17/bitcoin-documentary-film-rise-rise-bitcoin-debut-tribeca-film-festival/
  227. ^ Hern, Alex (30 April 2014). "MIT students to get $100 worth of bitcoin from Wall Street donor". The Guardian. Retrieved 1 May 2014.
  228. ^ Jack Smith IV (3 June 2014). "NY Congressional Candidate Jeff Kurzon". BetaBeat. Retrieved 4 June 2014.

Further reading