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Monday, November 21, 2022

Bitcoin

From Wikipedia, the free encyclopedia

Cryptoeconomics is an evolving economic paradigm for a cross-disciplinary approach to the study of digital economies and decentralized finance (DeFi) applications. Cryptoeconomics integrates concepts and principles from traditional economics, cryptography, computer science, and mathematical game theory disciplines. Just as traditional economics provides a theoretical foundation for traditional financial (a.k.a., Centralized Finance or CeFi) services, cryptoeconomics provides a theoretical foundation for DeFi services bought and sold via fiat cryptocurrencies, and legally bound by smart contracts.

Definitions and Goals

The term cryptoeconomics was coined by the Ethereum community during its formative years (2014-2015), but was initially inspired by the application of economic incentives in the original Bitcoin protocol in 2008. Although the phrase is typically attributed to Vitalik Buterin, the earliest public documented usage is a 2015 talk by Vlad Zamfir entitled “What is Cryptoeconomics?”. Zamfir's view of cryptoeconomics is relatively broad and academic: "... a formal discipline that studies protocols that govern the production, distribution, and consumption of goods and services in a decentralized digital economy. Cryptoeconomics is a practical science that focuses on the design and characterization of these protocols". Alternatively, in a 2017 talk, Buterin's view is more narrow and pragmatic: “... a methodology for building systems that try to guarantee certain kinds of information security properties".

The primary goals of cryptoeconomics are to understand how to fund, design, develop, and facilitate the operations of decentralized finance (DeFi) systems, and to apply economic incentives and penalties to regulate the distribution of goods and services in emerging digital economies.

Concepts and principles

Economics

Applies to cryptoeconomics as well as traditional economics.|alt=Graph depicting Quantity on X-axis and Price on Y-axis]] Cryptoeconomics may be considered an evolution of digital economics, which in turn evolved from traditional economics (commonly divided into microeconomics and macroeconomics). Consequently, traditional economic concepts regarding production, distribution, and consumption of goods and services also apply to cryptoeconomics. For example, these include Adam Smith's three basic laws of economics: Law of Supply and Demand, Law of Self Interest, and Law of Competition. They also include more modern economic concepts, such as fiat money theory and Modern Monetary Theory (MMT).

Cryptography

asymmetric (private key) encryption: Anyone can encrypt messages using a public key, but only the holder of the paired private key can decrypt such a message. System security is dependent upon secrecy of the private key.

Cryptography is the practice and study of secure communication techniques in the presence of adversarial behavior. More specifically, cryptography is concerned with creating and analyzing protocols that prevent third parties from reading private messages, and addresses various detailed aspects of information security, such as data confidentiality, integrity, authentication, and non-repudiation. Cryptographic techniques are essential to ensure that DeFi electronic commerce transactions are secure and generally irreversible. These cryptographic techniques include:

Computer science

peer-to-peer (P2P) network architecture: Networked computer nodes ("peers") share resources among each other without the need of centralized administrative (server) system.

Computer science, the study and practice of computation, automation, and information, is essential to ensure that DeFi electronic commerce transactions are both distributed and decentralized. Computer science techniques applied to cryptoeconomics include:

Mathematical game theory

Byzantine Generals Problem: If all generals attack in coordination, battle is won (left). If two generals falsely declare they intend to attack, but instead retreat, battle is lost (right).

Game theory uses mathematical models to study rational human decision-making within interactive, dynamic environments. Game theory has been proven fundamental to the development of the cryptocurrencies and blockchains that underlie cryptoeconomics, and is one of the reasons why the Bitcoin blockchain has not yet been compromised more than a decade since its creation, despite numerous attempts. Notable mathematical game theory models applied to cryptoeconomics include:

History

The historical roots of cryptoeconomics can be traced to the rise of altcoins (alternative cryptocurrency coins), prominent among them the Ethereum project, which in 2015 pioneered the integration of Turing-complete (computationally complete) smart contracts into its blockchain, thereby enabling a wide range of Decentralized Finance (DeFi) applications.

Cryptoeconomic subdisciplines

Similar to how traditional economics is divided into macroeconomics (regional, national, and international economics) and microeconomics (individual and enterprise economics) subdisciplines, cryptoeconomics can be divided into crypto-macreconomics and crypto-microeconomics subdisciplines.

Crypto-macroeconomics

Crypto-macroeconomics is concerned with the regional, national, and international regulation of cryptocurrencies and DeFi transactions. The Group of Seven (G7) governments' interest in cryptocurrencies became evident in August 2014, when the United Kingdom (UK) Treasury commissioned a study of cryptocurrencies and their potential role in the UK economy, and issued its final report in January 2021. In June 2021, El Salvador became the first country to accept Bitcoin as legal tender. In August 2021, Cuba followed with a legal resolution to recognize and regulate cryptocurrencies such as Bitcoin. However, in September 2021, the government of China, the single largest market for cryptocurrency, declared all cryptocurrency transactions illegal, completing a crackdown on cryptocurrency that had previously banned the operation of intermediaries and miners within China.

Crypto-microeconomics

Crypto-microeconomics is concerned with the individual and enterprise usages of cryptocurrencies and DeFi transactions. A strong majority of USA adults have heard about major cryptocurrencies (Bitcoin, Ether), and 16% say they personally have invested in, traded, or otherwise used one. More than 300 million people use cryptocurrency worldwide, and approximately 46 million Americans have invested in Bitcoin.

Criticisms and controversies

Bitcoin, along with other cryptocurrencies, has been described as an economic bubble by many distinguished economists, including Robert Shiller, Joseph Stiglitz, Richard Thaler, Paul Krugman, and Nouriel Roubini. In addition, Bitcoin and other cryptocurrencies have been criticized for the amount of electricity required for cryptocurrency "mining" (blockchain transaction validation), and for their use to purchase illegal goods.

Economics of bitcoin

From Wikipedia, the free encyclopedia

Bitcoin is a digital asset designed by its pseudonymous inventor, Satoshi Nakamoto, to work as a currency.

Since Bitcoin's first appearance in 2008, it has generated a wide variety of responses and analyses.

Classification

Bitcoin is a digital asset designed by its inventor, Satoshi Nakamoto, to work as a currency. It is commonly referred to with terms like: digital currency, digital cash, virtual currency, electronic currency, digital gold, or cryptocurrency.

The question whether bitcoin is a currency or not is disputed. Bitcoins have three useful qualities in a currency, according to The Economist in January 2015: they are "hard to earn, limited in supply and easy to verify". Economists define money as a store of value, a medium of exchange and a unit of account, and agree that bitcoin has some way to go to meet all these criteria. It does best as a medium of exchange: As of March 2014, the bitcoin market suffered from volatility, limiting the ability of bitcoin to act as a stable store of value, and retailers accepting bitcoin use other currencies as their principal unit of account.

Classification of bitcoin by the United States government is to date unclear with multiple conflicting rulings. In 2013 Judge Amos L. Mazzant III of the United States District Court for the Eastern District of Texas stated that "Bitcoin is a currency or form of money". In July 2016, Judge Teresa Mary Pooler of Eleventh Judicial Circuit Court of Florida cleared Michell Espinoza in State of Florida v. Espinoza in money-laundering charges he faced involving his use of bitcoin. Judge Pooler stated "Bitcoin may have some attributes in common with what we commonly refer to as money, but differ in many important aspects, they are certainly not tangible wealth and cannot be hidden under a mattress like cash and gold bars." In September 2016, a ruling by Judge Alison J. Nathan of United States District Court for the Southern District of New York contradicted the Florida Espinoza ruling stating "Bitcoins are funds within the plain meaning of that term.— Bitcoins can be accepted as a payment for goods and services or bought directly from an exchange with a bank account. They therefore function as pecuniary resources and are used as a medium of exchange and a means of payment." The U.S. Treasury categorizes bitcoin as a decentralized virtual currency. The Commodity Futures Trading Commission classifies bitcoin as a commodity, and the Internal Revenue Service classifies it as an asset.

The South African Revenue Service, the legislation of Canada, the Ministry of Finance of the Czech Republic and several others classify bitcoin as an intangible asset.

The Bundesbank says that bitcoin is not a virtual currency or digital money. It recommends using the term "crypto token".

The People's Bank of China has stated that bitcoin "is fundamentally not a currency but an investment target".

Journalists and academics also debate what to call bitcoin. Some media outlets do make a distinction between "real" money and bitcoins, while others call bitcoin real money. The Wall Street Journal declared it a commodity in December 2013. A Forbes journalist referred to it as digital collectible. Two University of Amsterdam computer scientists proposed the term "money-like informational commodity".

In addition to the above, bitcoin is also characterized as a payment system.

General use

According to research produced by Cambridge University in 2017, there are between 2.9 million and 5.8 million unique users actively using a cryptocurrency wallet, most of them using bitcoin. The number of active users has grown significantly since 2013 (there were 0.3 to 1.3 million unique users at the time).

Buying and selling

A bitcoin ATM in California

Bitcoins can be bought and sold both on- and offline. Participants in online exchanges offer bitcoin buy and sell bids. Using an online exchange to obtain bitcoins entails some risk, and, according to a study published in April 2013, 45% of exchanges fail and take client bitcoins with them. Exchanges have since implemented measures to provide proof of reserves in an effort to convey transparency to users. Offline, bitcoins may be purchased directly from an individual or at a bitcoin ATM. Bitcoin machines are not however traditional ATMs. Bitcoin kiosks are machines connected to the Internet, allowing the insertion of cash in exchange for bitcoins. Bitcoin kiosks do not connect to a bank and may also charge transaction fees as high as 7% and exchange rates US$50 over rates from elsewhere.

As of 2016 it was estimated there were over 800 bitcoin ATMs operating globally, the majority (500+) being in the United States.

Price and volatility

 
Price of bitcoin, logarithmic scale
 
Annual volatility of bitcoin
 
Liquidity calculated as a 365-day running sum of transaction outputs in USD, semilogarithmic plot

According to Mark T. Williams, as of 2014, bitcoin has volatility seven times greater than gold, eight times greater than the S&P 500, and 18 times greater than the U.S. dollar.

Attempting to explain the high volatility, a group of Japanese scholars stated that there is no stabilization mechanism. The Bitcoin Foundation contends that high volatility is due to insufficient liquidity, while a Forbes journalist claims that it is related to the uncertainty of its long-term value, and the high volatility of a startup currency makes sense, "because people are still experimenting with the currency to figure out how useful it is."

There are uses where volatility does not matter, such as online gambling, tipping, and international remittances. As of 2014, pro-bitcoin venture capitalists argued that the greatly increased trading volume that planned high-frequency trading exchanges would generate is needed to decrease price volatility.

The price of bitcoins has gone through various cycles of appreciation and depreciation referred to by some as bubbles and busts. In 2011, the value of one bitcoin rapidly rose from about US$0.30 to US$32 before returning to US$2. In the latter half of 2012 and during the 2012–13 Cypriot financial crisis, the bitcoin price began to rise, reaching a high of US$266 on 10 April 2013, before crashing to around US$50. On 29 November 2013, the cost of one bitcoin rose to the all-time peak of US$1,242. Some evidence suggests that part of this peak in the price of bitcoin was due to price manipulation. In 2014, the price fell sharply, and as of April remained depressed at little more than half 2013 prices. As of August 2014 it was under US$600.

In January 2015, noting that the bitcoin price had dropped to its lowest level since spring 2013 – around US$224 – The New York Times suggested that "[w]ith no signs of a rally in the offing, the industry is bracing for the effects of a prolonged decline in prices. In particular, bitcoin mining companies, which are essential to the currency's underlying technology, are flashing warning signs." Also in January 2015, Business Insider reported that deep web drug dealers were "freaking out" as they lost profits through being unable to convert bitcoin revenue to cash quickly enough as the price declined – and that there was a danger that dealers selling reserves to stay in business might force the bitcoin price down further.

Economic theory suggests that the volatility of the price of bitcoin will drop when business and consumer usage of bitcoin increases. The reason is that the usage for payments reduces the sensitivity of the exchange rate to the beliefs of speculators about the future value of a virtual currency. According to The Wall Street Journal, as of April 2016, bitcoin is starting to look slightly more stable than gold. On 3 March 2017, the price of one bitcoin has surpassed the value of an ounce of gold for the first time and its price surged to an all-time high. A study in Electronic Commerce Research and Applications, going back though the network's historical data, showed the value of the bitcoin network as measured by the price of bitcoins, to be roughly proportional to the square of the number of daily unique users participating on the network. This is a form of Metcalfe's law and suggests that the network was demonstrating network effects proportional to its level of user adoption.

As a speculative bubble

Bitcoin has been characterized as a speculative bubble by eight laureates of the Nobel Memorial Prize in Economic Sciences: Paul Krugman, Robert J. Shiller, Joseph Stiglitz, Richard Thaler, James Heckman, Thomas Sargent, Angus Deaton, and Oliver Hart; and by central bank officials including Alan Greenspan, Ben Bernanke, Janet Yellen, Agustín Carstens, Vítor Constâncio, and Nout Wellink.

The investors Warren Buffett and George Soros have respectively characterized it as a "mirage" and a "bubble"; while the business executive Jack Ma has called it a "bubble".

Views of economists

In 2014, Nobel laureate Robert J. Shiller stated that bitcoin "exhibited many of the characteristics of a speculative bubble"; in 2017, Shiller wrote that bitcoin was the best current example of a speculative bubble.

Economist John Quiggin in 2013 said "bitcoins are the most demonstrably valueless financial asset ever created".

Researchers Neil Gandal, JT Hamrick, Tyler Moore, and Tali Oberman claimed that in late 2013, price manipulation by one person likely caused a price spike from US$150 to more than US$1000.

Nobel laureate Joseph Stiglitz in 2017 said "It’s a bubble that’s going to give a lot of people a lot of exciting times as it rides up and then goes down." He emphasized its use by criminals, its lack of a socially useful purpose, and said that it should be outlawed.

Nobel laureate Paul Krugman wrote in 2018 that bitcoin is "a bubble wrapped in techno-mysticism inside a cocoon of libertarian ideology". He criticized it as a very slow and expensive means of payment, used mostly to buy blackmarket goods, without a "tether to reality".

Nobel laureate Richard Thaler emphasizes the irrationality in the bitcoin market that has led to the bubble, demonstrating the irrationality with the example of firms that have added the word blockchain to their names which have then had large increases in their stock price. The extremely high volatility in bitcoin's price also is due to irrationality according to Thaler.

Four Nobel laureates, James Heckman, Thomas Sargent, Angus Deaton, and Oliver Hart, characterized bitcoin as a bubble at a joint press conference in 2018. Hart cited Christopher Sims's work showing no intrinsic value to bitcoin. Heckman compared bitcoin to the tulip bubble. Deaton pointed to bitcoin's use by criminals.

Professor Nouriel Roubini of New York University has called bitcoin the "mother of all bubbles", writing that the underlying blockchain technology has "massive obstacles standing in its way", including a lack of "common and universal protocols" of the kind that enabled the early Internet. According to Roubini, bitcoin has failed as a unit of account, a means of payment, and as a store of value; he calls the claim that bitcoin cannot be debased "fraudulent". "Scammers, swindlers, charlatans, and carnival barkers (all conflicted insiders) have tapped into clueless retail investors' FOMO ('fear of missing out'), and taken them for a ride," he writes.

Views of central bank officials

Early claims that bitcoin was a bubble focused on the lack of any intrinsic value of bitcoin. These claims include that of former Federal Reserve Chairman Alan Greenspan in 2013. He stated "You really have to stretch your imagination to infer what the intrinsic value of Bitcoin is. I haven't been able to do it."

In 2017 Greenspan compared bitcoin to the Continental dollar, which ultimately collapsed. He said "Humans buy all sorts of things that aren't worth anything. People gamble in casinos when the odds are against them. It has never stopped anybody."

Former Fed Chair Ben Bernanke (in 2015) and outgoing Fed Chair Janet Yellen (in 2017) have both expressed concerns about the stability of bitcoin's price and its lack of use as a medium of transactions.

Agustín Carstens, head of the Bank of International Settlements, has called bitcoin "a combination of a bubble, a Ponzi scheme and an environmental disaster", and warned of cryptocurrencies undermining public trust in the financial system.

David Andolfatto, a vice president at the Federal Reserve Bank of St. Louis, stated, "Is bitcoin a bubble? Yes, if bubble is defined as a liquidity premium." According to Andolfatto, the price of bitcoin "consists purely of a bubble".

Comparisons of bitcoin to the tulip mania of seventeenth-century Holland have been made by the vice-president of the European Central Bank, Vítor Constâncio and by former president of the Dutch Central Bank, Nout Wellink. In 2013, Wellink remarked, "This is worse than the tulip mania ... At least then you got a tulip [at the end], now you get nothing."

Views of investors and executives

American investor Warren Buffett warned investors about bitcoin in 2014, "Stay away from it. It's a mirage, basically." He repeated the warning in 2018 calling bitcoin "probably rat poison squared". He believes that bitcoin is a non-productive asset. "When you're buying nonproductive assets, all you're counting on is the next person is going to pay you more because they're even more excited about another next person coming along."

Buffett's close associate Charlie Munger is even more direct in his disdain. Trading cryptocurrencies is "just dementia" according to Munger. Bitcoin is "worthless" and a "turd".

John Bogle, the founder of The Vanguard Group, is also very direct "Avoid bitcoin like the plague. Did I make myself clear? .... There is nothing to support bitcoin except the hope that you will sell it to someone for more than you paid for it."

George Soros, answering an audience question after a speech in Davos, Switzerland, in 2018, said that cryptocurrencies are not a store of value but are an economic bubble. Nevertheless, they may not crash due to the rising influence of dictators trying to "build a nest egg abroad".

James Chanos, known as the "dean of the short sellers", believes that bitcoin and other cryptocurrencies are a mania and useful only for tax avoidance or otherwise hiding income from the government. Bitcoin "is simply a security speculation game masquerading as a technological breakthrough in monetary policy".

Two lead software developers of bitcoin, Gavin Andresen and Mike Hearn, have warned that bubbles may occur.

On 13 September 2017, Jamie Dimon referred to bitcoin to as a "fraud", comparing it to pyramid schemes, and stated that JPMorgan Chase would fire employees trading while the company released a report critical of the cryptocurrency. However, in a January 2018 interview Jamie Dimon voiced regrets about his earlier bitcoin remarks, and noted "The blockchain is real, You can have cryptodollars in yen and stuff like that. ICOs ... you got to look at everyone individually."

Alibaba chairman Jack Ma stated in 2018, "There is no bubble for blockchain, but there's a bitcoin bubble"[60] and "[blockchain] technology itself isn’t the bubble, but bitcoin likely is".

Fraud concerns

Some journalists, economists, and the central bank of Estonia have voiced concerns that bitcoin is a Ponzi scheme. In 2013, Eric Posner, a law professor at the University of Chicago, stated that "a real Ponzi scheme takes fraud; bitcoin, by contrast, seems more like a collective delusion." In 2014 reports by both the World Bank and the Swiss Federal Council examined the concerns and came to the conclusion that bitcoin is not a Ponzi scheme. In 2017 billionaire Howard Marks referred to bitcoin as a pyramid scheme.

On 12 September 2017, Jamie Dimon, CEO of JPMorgan Chase, called bitcoin a "fraud" and said he would fire anyone in his firm caught trading it. Zero Hedge claimed that the same day Dimon made his statement, JP Morgan also purchased a large amount of bitcoins for its clients.

Value forecasts

Financial journalists and analysts, economists, and investors have attempted to predict the possible future value of bitcoin. In April 2013, economist John Quiggin stated, "bitcoins will attain their true value of zero sooner or later, but it is impossible to say when". A similar forecast was made in November 2014 by economist Kevin Dowd.

In December 2013, finance professor Mark T. Williams forecast that bitcoin would trade for less than $10 by mid-year 2014. In the indicated period bitcoin has exchanged as low as $344 (April 2014) and during July 2014 the bitcoin low was $609. In December 2014, Williams said, "The probability of success is low, but if it does hit, the reward will be very large."

In November 2014, David Yermack, Professor of Finance at New York University Stern School of Business, forecast that in November 2015 bitcoin may be all but worthless. In the indicated period bitcoin has exchanged as low as $176.50 (January 2015) and during November 2015 the bitcoin low was $309.90.

In May 2013, Bank of America FX and Rate Strategist David Woo forecast a maximum fair value per bitcoin of $1,300. Bitcoin investor Cameron Winklevoss stated in December 2013 that the "small bull case scenario for bitcoin is... 40,000 USD a coin".

Obituaries

The "death" of bitcoin has been proclaimed numerous times. One journalist has recorded 29 such "obituaries" as of early 2015.

Forbes magazine declared bitcoin "dead" in June 2011, followed by Gizmodo Australia in August 2011. Wired magazine wrote it had "expired" in December 2012. Ouishare Magazine declared, "game over, bitcoin" in May 2013, and New York Magazine stated bitcoin was "on its path to grave" in June 2013. Reuters published an "obituary" for bitcoin in January 2014. Street Insider declared bitcoin "dead" in February 2014, followed by The Weekly Standard in March 2014, Salon in March 2014, Vice News in March 2014, and Financial Times in September 2014. In January 2015, USA Today stated bitcoin was "headed to the ash heap", and The Telegraph declared "the end of bitcoin experiment". In January 2016, former bitcoin developer Mike Hearn called bitcoin a "failed project".

Peter Greenhill, Director of E-Business Development for the Isle of Man, commenting on the obituaries paraphrased Mark Twain saying "reports of bitcoin's death have been greatly exaggerated".

Reception

Some economists have responded positively to bitcoin while others have expressed skepticism. François R. Velde, Senior Economist at the Chicago Fed, described it as "an elegant solution to the problem of creating a digital currency". 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 its value. Economist John Quiggin has criticized bitcoin as "the final refutation of the efficient-market hypothesis".

David Andolfatto, Vice President at the Federal Reserve Bank of St. Louis, stated that bitcoin is a threat to the establishment, which he argues is a good thing for the Federal Reserve System and other central banks, because it prompts these institutions to operate sound policies.

Free software movement activist Richard Stallman has criticized the lack of anonymity and called for reformed development. 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. Bill Gates, in relation to the cost of moving money from place to place in an interview for Bloomberg L.P. stated: "Bitcoin is exciting because it shows how cheap it can be."

In November 2013, three US government officials testified at senate hearings that "Bitcoin has legitimate uses". According to The Washington Post, "Most of the other witnesses echoed those sentiments."

Acceptance by merchants

Bitcoins were accepted in this café in Delft in the Netherlands in 2013.

Most bitcoin transactions take place on a cryptocurrency exchange, rather than being used in transactions with merchants. Delays processing payments through the blockchain of about ten minutes make bitcoin use very difficult in a retail setting. Prices are not usually quoted in units of bitcoin and many trades involve one, or sometimes two, conversions into conventional currencies. Merchants that do accept bitcoin payments may use payment service providers to perform the conversions.

In 2017 and 2018 bitcoin's acceptance among major online retailers included only three of the top 500 U.S. online merchants, down from five in 2016. Reasons for this decline include high transaction fees due to bitcoin's scalability issues and long transaction times.

Bloomberg reported that the largest 17 crypto merchant-processing services handled $69 million in June 2018, down from $411 million in September 2017. Bitcoin is "not actually usable" for retail transactions because of high costs and the inability to process chargebacks, according to Nicholas Weaver, a researcher quoted by Bloomberg. High price volatility and transaction fees make paying for small retail purchases with bitcoin impractical, according to economist Kim Grauer.

A bitcoin ATM in Vienna – Westbahnhof

Bitcoin started to be accepted also for real estate payments in late 2017. The first recorded sale of a house in exchange for bitcoin happened in September 2017, when Texas based Kuper Sotheby's International Realty brokered the deal using bitpay.com to process the payment.

Two months later, a first recorded sale of apartment in the world and first real estate property in Europe was sold for bitcoin in November 2017 in the Czech republic. The Czech real estate agency HOME Hunters brokered a deal of a three-room apartment for a Russian buyer without using a payment service providers at all.

Some U.S. political candidates, including New York City Democratic Congressional candidate Jeff Kurzon have said they would accept campaign donations in bitcoin.

Payment service providers

Merchants accepting bitcoin, such as Dish Network, use the services of bitcoin payment service providers such as BitPay or Coinbase. When a customer pays in bitcoin, the payment service provider accepts the bitcoin on behalf of the merchant, directly converts it, and sends the obtained amount to merchant's bank account, charging a fee of less than 1 percent for the service.

Use in retail transactions

Due to the design of bitcoin, all retail figures are only estimates. According to Tim Swanson, head of business development at a Hong Kong-based cryptocurrency technology company, in 2014, daily retail purchases made with bitcoin were worth about $2.3 million. MIT Technology review estimates that, as of February 2015, fewer than 5,000 bitcoins per day (worth roughly $1.2 million at the time) were being used for retail transactions, and concludes that in 2014 "it appears there has been very little if any increase in retail purchases using bitcoin."

Financial institutions

Bitcoin companies have had difficulty opening traditional bank accounts because lenders have been leery of bitcoin's links to illicit activity. According to Antonio Gallippi, a co-founder of BitPay, "banks are scared to deal with bitcoin companies, even if they really want to". In 2014, the National Australia Bank closed accounts of businesses with ties to bitcoin, and HSBC refused to serve a hedge fund with links to bitcoin. Australian banks in general have been reported as closing down bank accounts of operators of businesses involving the currency; this has become the subject of an investigation by the Australian Competition & Consumer Commission. Nonetheless, Australian banks have adopted the blockchain technology on which bitcoin is based.

In September 2019 the Central Bank of Venezuela, at the request of PDVSA, ran tests to determine if bitcoin and Ethereum could be held in central bank's reserves. The request was motivated by oil company's goal to pay its suppliers.

As an investment

Some Argentinians have bought bitcoins to protect their savings against high inflation or the possibility that governments could confiscate savings accounts. During the 2012–2013 Cypriot financial crisis, bitcoin purchases in Cyprus rose due to fears that savings accounts would be confiscated or taxed.

Other methods of investment are bitcoin funds. The first regulated bitcoin fund was established in Jersey in July 2014 and approved by the Jersey Financial Services Commission. Also, c. 2012 an attempt was made by Cameron and Tyler Winklevoss (who in April 2013 claimed they owned nearly 1% of all bitcoins in existence) to establish a bitcoin ETF. As of 10 March 2017 the bitcoin ETF was declined by the SEC because of regulatory concerns. The price fell 15% in a few minutes, but soon mostly recovered. As of early 2015, they have announced plans to launch a New York-based bitcoin exchange named Gemini, which has received approval to launch on 5 October 2015. On 4 May 2015, Bitcoin Investment Trust started trading on the OTCQX market as GBTC.

In 2013 and 2014, the European Banking Authority and the Financial Industry Regulatory Authority (FINRA), a United States self-regulatory organization, warned that investing in bitcoins carries significant risks. Forbes named bitcoin the best investment of 2013. In 2014, Bloomberg named bitcoin one of its worst investments of the year. In 2015, bitcoin topped Bloomberg's currency tables.

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. In May 2015, Intercontinental Exchange Inc., parent company of the New York Stock Exchange, announced a bitcoin index initially based on data from Coinbase transactions.

According to Bloomberg, in 2013 there were about 250 bitcoin wallets with more than $1 million worth of bitcoins. The number of bitcoin millionaires is uncertain as people can have more than one wallet.

Venture capital

Venture capitalists, such as Peter Thiel's Founders Fund, which invested US$3 million in BitPay, do not purchase bitcoins themselves, instead funding bitcoin infrastructure like companies that provide payment systems to merchants, exchanges, wallet services, etc. In 2012, an incubator for bitcoin-focused start-ups was founded by Adam Draper, with financing help from his father, venture capitalist Tim Draper, one of the largest bitcoin holders after winning an auction of 30,000 bitcoins, at the time called 'mystery buyer'. The company's goal is to fund 100 bitcoin businesses within 2–3 years with $10,000 to $20,000 for a 6% stake. Investors also invest in bitcoin mining. According to a 2015 study by Paolo Tasca, bitcoin startups raised almost $1 billion in three years (Q1 2012 – Q1 2015).

Crowdfunding

Bitcoin is useful for crowdfunding. For example, one college football sign netted over $20,000 in donations for a bitcoin enthusiast. He was shown by local TV company with a broadsheet "Hi mom, send bitcoins".

Political economy

The decentralization of money offered by virtual currencies like bitcoin has its theoretical roots in the Austrian school of economics such as subjective theory of value, especially with Friedrich von Hayek in his book Denationalisation of Money: The Argument Refined, in which he advocates a complete free market in the production, distribution and management of money to end the monopoly of central banks.

Bitcoin appeals to tech-savvy libertarians, because it so far exists outside the institutional banking system and the control of governments. However, researchers looking to uncover the reasons for interest in bitcoin did not find evidence in Google search data that this was linked to libertarianism.

Bitcoin's appeal reaches from left wing critics, "who perceive the state and banking sector as representing the same elite interests, ... recognising in it the potential for collective direct democratic governance of currency" and socialists proposing their "own states, complete with currencies", to right wing critics suspicious of big government, at a time when activities within the regulated banking system were responsible for the severity of the financial crisis of 2007–08, "because governments are not fully living up to the responsibility that comes with state-sponsored money". Two WSJ journalists describe bitcoin in their book as "about freeing people from the tyranny of centralised trust".

Bitcoin network

From Wikipedia, the free encyclopedia
 
A diagram of a bitcoin transfer
 
Number of bitcoin transactions per month (logarithmic scale)

The bitcoin network is a peer-to-peer payment network that operates on a cryptographic protocol. Users send and receive bitcoins, the units of currency, by broadcasting digitally signed messages to the network using bitcoin cryptocurrency wallet software. Transactions are recorded into a distributed, replicated public database known as the blockchain, with consensus achieved by a proof-of-work system called mining. Satoshi Nakamoto, the designer of bitcoin, claimed that design and coding of bitcoin began in 2007. The project was released in 2009 as open source software.

The network requires minimal structure to share transactions. An ad hoc decentralized network of volunteers is sufficient. Messages are broadcast on a best-effort basis, and nodes can leave and rejoin the network at will. Upon reconnection, a node downloads and verifies new blocks from other nodes to complete its local copy of the blockchain.

Transactions

An actual bitcoin transaction including the fee from a web-based cryptocurrency exchange to a hardware wallet
 
The best chain   consists of the longest series of transaction records from the genesis block   to the current block or record. Orphaned records   exist outside of the best chain.

A bitcoin is defined by a sequence of digitally signed transactions that began with the bitcoin's creation, as a block reward. The owner of a bitcoin transfers it by digitally signing it over to the next owner using a bitcoin transaction, much like endorsing a traditional bank check. A payee can examine each previous transaction to verify the chain of ownership. Unlike traditional check endorsements, bitcoin transactions are irreversible, which eliminates risk of chargeback fraud.

Although it is possible to handle bitcoins individually, it would be unwieldy to require a separate transaction for every bitcoin in a transaction. Transactions are therefore allowed to contain multiple inputs and outputs, allowing bitcoins to be split and combined. Common transactions will have either a single input from a larger previous transaction or multiple inputs combining smaller amounts, and one or two outputs: one for the payment, and one returning the change, if any, to the sender. Any difference between the total input and output amounts of a transaction goes to miners as a transaction fee.

Mining

GPU-based mining rig, 2012
 
A Bitcoin mining farm, 2018

To form a distributed timestamp server as a peer-to-peer network, bitcoin uses a proof-of-work system. This work is often called bitcoin mining.

During mining, practically the entire computing power of the Bitcoin network is used to solve cryptographic tasks, the proof of work. Their purpose is to ensure that the generation of valid blocks involves a certain amount of effort, so that subsequent modification of the block chain, such as in the 51% attack scenario, can be practically ruled out. Because of the difficulty, miners form "mining pools" to get payouts despite these high power requirements, costly hardware deployments, and/or hardware under their own control. The largest proportion of mining pools are based in China, which is also where most of the miners—or about 75% of the computing power—of the cryptocurrency are based.

Requiring a proof of work to accept a new block to the blockchain was Satoshi Nakamoto's key innovation. The mining process involves identifying a block that, when hashed twice with SHA-256, yields a number smaller than the given difficulty target. While the average work required increases in inverse proportion to the difficulty target, a hash can always be verified by executing a single round of double SHA-256.

For the bitcoin timestamp network, a valid proof of work is found by incrementing a nonce until a value is found that gives the block's hash the required number of leading zero bits. Once the hashing has produced a valid result, the block cannot be changed without redoing the work. As later blocks are chained after it, the work to change the block would include redoing the work for each subsequent block. If there is a deviation in consensus then a blockchain fork can occur.

Majority consensus in bitcoin is represented by the longest chain, which required the greatest amount of effort to produce. If a majority of computing power is controlled by honest nodes, the honest chain will grow fastest and outpace any competing chains. To modify a past block, an attacker would have to redo the proof-of-work of that block and all blocks after it and then surpass the work of the honest nodes. The probability of a slower attacker catching up diminishes exponentially as subsequent blocks are added.

Mining difficulty has increased significantly.

To compensate for increasing hardware speed and varying interest in running nodes over time, the difficulty of finding a valid hash is adjusted roughly every two weeks. If blocks are generated too quickly, the difficulty increases and more hashes are required to make a block and to generate new bitcoins.

Difficulty and mining pools

The largest Bitcoin mining pools as of April 2020 by nation in which they are based

Bitcoin mining is a competitive endeavor. An "arms race" has been observed through the various hashing technologies that have been used to mine bitcoins: basic central processing units (CPUs), high-end graphics processing units (GPUs), field-programmable gate arrays (FPGAs) and application-specific integrated circuits (ASICs) all have been used, each reducing the profitability of the less-specialized technology. Bitcoin-specific ASICs are now the primary method of mining bitcoin and have surpassed GPU speed by as much as 300-fold. The difficulty within the mining process involves self-adjusting to the network's accumulated mining power. As bitcoins have become more difficult to mine, computer hardware manufacturing companies have seen an increase in sales of high-end ASIC products.

Computing power is often bundled together or "pooled" to reduce variance in miner income. Individual mining rigs often have to wait for long periods to confirm a block of transactions and receive payment. In a pool, all participating miners get paid every time a participating server solves a block. This payment depends on the amount of work an individual miner contributed to help find that block.

Energy sources and consumption

Bitcoin electricity consumption as of 2021

In 2013, Mark Gimein estimated electricity consumption to be about 40.9 megawatts (982 megawatt-hours a day). In 2014, Hass McCook estimated 80.7 megawatts (80,666 kW). As of 2015, The Economist estimated that even if all miners used modern facilities, the combined electricity consumption would be 166.7 megawatts (1.46 terawatt-hours per year). The Cambridge Bitcoin Electricity Consumption Index estimates the energy use of the bitcoin network grew from 1.95 terawatt-hours per year at the end of 2014, to 77.1 terawatt-hours per year by the end of 2019.

Seeking lower electricity costs, some bitcoin miners have set up in places like Iceland where geothermal energy is cheap and cooling Arctic air is free. Chinese bitcoin miners are known to use hydroelectric power in Tibet to reduce electricity costs. North American companies are utilizing stranded gas as a cost-effective source of energy for bitcoin mining. In West Texas, wind powers bitcoin mining. As of April 2021, at least one-third of Bitcoin mining was powered by coal in China's Xinjiang region.

A 2021 study found that carbon emissions from Bitcoin mining in China—where a majority of the proof-of-work algorithm that generated economic value was computed prior to mid-2021—had accelerated rapidly in the late 2010s, are largely fueled by nonrenewable sources and was expected to exceed total annual emissions of countries like Italy and Spain during 2016, interfering with international climate change mitigation commitments. It was also found that in 2021, bitcoin mining consumed more energy than the country of New Zealand. A formal Chinese ban on cryptocurrency mining operations in May 2021—reiterated in both September and November—resulted in the relocation of a large majority of mining equipment away from China. Yet as many as 20 percent of "all the world's bitcoin miners remain in China. This is well off its peak of around 65% to 75% of the global market." By December 2021, the global hashrate had mostly recovered to a level before China's crackdown, with increased shares of the total mining power coming from the U.S. (35.4%), Kazakhstan (18.1%), and Russia (11%) instead.

A 2022 survey on technologies approached cryptocurrencies' technological and environmental issues from many perspectives and noted the plans of using the methods of unconventional computing and grid computing to make bitcoin and ether both greener and more justified.

Process

Avalon ASIC-based mining machine

A rough overview of the process to mine bitcoins involves:

  1. New transactions are broadcast to all nodes.
  2. Each miner node collects new transactions into a block.
  3. Each miner node works on finding a proof-of-work code for its block.
  4. When a node finds a proof-of-work, it broadcasts the block to all nodes.
  5. Receiving nodes validate the transactions it holds and accept only if all are valid.
  6. Nodes express their acceptance by moving to work on the next block, incorporating the hash of the accepted block.

Mined bitcoins

Diagram showing how bitcoin transactions are verified

By convention, the first transaction in a block is a special transaction that produces new bitcoins owned by the creator of the block. This is the incentive for nodes to support the network. It provides the way to move new bitcoins into circulation. The reward for mining halves every 210,000 blocks. It started at 50 bitcoin, dropped to 25 in late 2012 and to 12.5 bitcoin in 2016. The most recent halving, which occurred in May 2020 (with block number 630,000), reduced the block reward to 6.25 bitcoin. This halving process is programmed to continue a maximum 64 times before new coin creation ceases.

Security

Various potential attacks on the bitcoin network and its use as a payment system, real or theoretical, have been considered. The bitcoin protocol includes several features that protect it against some of those attacks, such as unauthorized spending, double spending, forging bitcoins, and tampering with the blockchain. Other attacks, such as theft of private keys, require due care by users.

Unauthorized spending

Unauthorized spending is mitigated by bitcoin's implementation of public-private key cryptography. For example, when Alice sends a bitcoin to Bob, Bob becomes the new owner of the bitcoin. Eve, observing the transaction, might want to spend the bitcoin Bob just received, but she cannot sign the transaction without the knowledge of Bob's private key.

Double spending

A specific problem that an internet payment system must solve is double-spending, whereby a user pays the same coin to two or more different recipients. An example of such a problem would be if Eve sent a bitcoin to Alice and later sent the same bitcoin to Bob. The bitcoin network guards against double-spending by recording all bitcoin transfers in a ledger (the blockchain) that is visible to all users, and ensuring for all transferred bitcoins that they have not been previously spent.

Race attack

If Eve offers to pay Alice a bitcoin in exchange for goods and signs a corresponding transaction, it is still possible that she also creates a different transaction at the same time sending the same bitcoin to Bob. By the rules, the network accepts only one of the transactions. This is called a race attack, since there is a race which transaction will be accepted first. Alice can reduce the risk of race attack stipulating that she will not deliver the goods until Eve's payment to Alice appears in the blockchain.

A variant race attack (which has been called a Finney attack by reference to Hal Finney) requires the participation of a miner. Instead of sending both payment requests (to pay Bob and Alice with the same coins) to the network, Eve issues only Alice's payment request to the network, while the accomplice tries to mine a block that includes the payment to Bob instead of Alice. There is a positive probability that the rogue miner will succeed before the network, in which case the payment to Alice will be rejected. As with the plain race attack, Alice can reduce the risk of a Finney attack by waiting for the payment to be included in the blockchain.

History modification

Each block that is added to the blockchain, starting with the block containing a given transaction, is called a confirmation of that transaction. Ideally, merchants and services that receive payment in bitcoin should wait for at least one confirmation to be distributed over the network, before assuming that the payment was done. The more confirmations that the merchant waits for, the more difficult it is for an attacker to successfully reverse the transaction in a blockchain—unless the attacker controls more than half the total network power, in which case it is called a 51% attack.

Deanonymisation of clients

Deanonymisation is a strategy in data mining in which anonymous data is cross-referenced with other sources of data to re-identify the anonymous data source. Along with transaction graph analysis, which may reveal connections between bitcoin addresses (pseudonyms), there is a possible attack which links a user's pseudonym to its IP address. If the peer is using Tor, the attack includes a method to separate the peer from the Tor network, forcing them to use their real IP address for any further transactions. The attack makes use of bitcoin mechanisms of relaying peer addresses and anti-DoS protection. The cost of the attack on the full bitcoin network is under €1500 per month.

Payment verification

Each miner can choose which transactions are included in or exempted from a block. A greater number of transactions in a block does not equate to greater computational power required to solve that block.

Upon receiving a new transaction a node must validate it: in particular, verify that none of the transaction's inputs have been previously spent. To carry out that check, the node needs to access the blockchain. Any user who does not trust his network neighbors, should keep a full local copy of the blockchain, so that any input can be verified.

As noted in Nakamoto's whitepaper, it is possible to verify bitcoin payments without running a full network node (simplified payment verification, SPV). A user only needs a copy of the block headers of the longest chain, which are available by querying network nodes until it is apparent that the longest chain has been obtained; then, get the Merkle tree branch linking the transaction to its block. Linking the transaction to a place in the chain demonstrates that a network node has accepted it, and blocks added after it further establish the confirmation.

Data in the blockchain

While it is possible to store any digital file in the blockchain, the larger the transaction size, the larger any associated fees become. The more information that is stored on each block means more information is stored on nodes, potentially creating "blockchain bloating." The first block of the Bitcoin blockchain, known as the "Genesis Block", contains a famous newspaper headline that may hint at Bitcoin's mission. Various items have been embedded, including URLs to websites, an ASCII art image of Ben Bernanke, material from the Wikileaks cables, prayers from bitcoin miners, and the original bitcoin whitepaper. Other important information is stored in the blockchain as well. In Blockchain: Insights You Need from Harvard Business Review, Tapscott, Lakhani, and Iansiti state "With blockchain, we can imagine a world in which contracts are embedded in digital code and stored in transparent, shared databases, where they are protected from deletion, tampering, and revision. Intermediaries like lawyers, brokers, and bankers might no longer be necessary. Individuals, organizations, machines, and algorithms would freely transact and interact with one another with little friction."

Criminal activity

The use of bitcoin by criminals has attracted the attention of financial regulators, legislative bodies, law enforcement, and the media. The FBI prepared an intelligence assessment, the SEC has issued a pointed warning about investment schemes using virtual currencies, and the U.S. Senate held a hearing on virtual currencies in November 2013.

Several news outlets have asserted that the popularity of bitcoins hinges on the ability to use them to purchase illegal goods. In 2014, researchers at the University of Kentucky found "robust evidence that computer programming enthusiasts and illegal activity drive interest in bitcoin, and find limited or no support for political and investment motives."

Black markets

A Carnegie Mellon University researcher estimated that in 2012, 4.5% to 9% of all transactions on all exchanges in the world were for drug trades on a single dark web drugs market, Silk Road. Child pornography, murder-for-hire, and weapons are also allegedly available on black market sites that sell in bitcoin. Due to the anonymous nature and the lack of central control on these markets, it is hard to know whether the services are real or just trying to take the bitcoins.

Several deep web black markets have been shut by authorities. In October 2013 Silk Road was shut down by U.S. law enforcement, leading to a short-term decrease in the value of bitcoin. In 2015, the founder of the site was sentenced to life in prison. Alternative sites were soon available, and in early 2014 the Australian Broadcasting Corporation reported that the closure of Silk Road had little impact on the number of Australians selling drugs online, which had actually increased. In early 2014, Dutch authorities closed Utopia, an online illegal goods market, and seized 900 bitcoins. In late 2014, a joint police operation saw European and American authorities seize bitcoins and close 400 deep web sites including the illicit goods market Silk Road 2.0. Law enforcement activity has resulted in several convictions. In December 2014, Charlie Shrem was sentenced to two years in prison for indirectly helping to send $1 million to the Silk Road drugs site, and in February 2015, its founder, Ross Ulbricht, was convicted on drugs charges and given a sentence of double life imprisonment plus 40 years.

Some black market sites may seek to steal bitcoins from customers. The bitcoin community branded one site, Sheep Marketplace, as a scam when it prevented withdrawals and shut down after an alleged bitcoins theft. In a separate case, escrow accounts with bitcoins belonging to patrons of a different black market were hacked in early 2014.

According to the Internet Watch Foundation, a UK-based charity, bitcoin is used to purchase child pornography, and almost 200 such websites accept it as payment. Bitcoin is not the sole way to purchase child pornography online, as Troels Oertling, head of the cybercrime unit at Europol, states, "Ukash and paysafecard... have [also] been used to pay for such material." However, the Internet Watch Foundation lists around 30 sites that exclusively accept bitcoins. Some of these sites have shut down, such as a deep web crowdfunding website that aimed to fund the creation of new child porn. Furthermore, hyperlinks to child porn websites have been added to the blockchain as arbitrary data can be included when a transaction is made.

Money laundering

Bitcoins may not be ideal for money laundering, because all transactions are public. Authorities—including the European Banking Authority, the FBI, National Treasury (South Africa) and the Financial Action Task Force of the G7—have expressed concerns that bitcoin may be used for money laundering.

In early 2014, an operator of a U.S. bitcoin exchange, Charlie Shrem, was arrested for money laundering. Subsequently, he was sentenced to two years in prison for "aiding and abetting an unlicensed money transmitting business".

Alexander Vinnik, an alleged owner of BTC-e, was arrested in Greece on 25 July 2017, on $4 billion money laundering charges for flouting anti-money laundering (AML) laws of the US. A report by the UK's Treasury and Home Office named "UK national risk assessment of money laundering and terrorist financing" (October 2015) found that, of the twelve methods examined in the report, bitcoin carries the lowest risk of being used for money laundering, with the most common money laundering method being the banks.

Roman Sterlingov was arrested on 27 April 2021 for allegedly laundering about 1.2 million BTC or US$336 million. According to reports from IRS Criminal Investigation, Sterlingov was the principal operator of a Cryptocurrency tumbler Bitcoin Fog, launched in 2011.

Ponzi scheme

In a Ponzi scheme using bitcoins, the Bitcoin Savings and Trust promised investors up to 7% weekly interest, and raised at least 700,000 bitcoins from 2011 to 2012. In July 2013, the U.S. Securities and Exchange Commission charged the company and its founder in 2013 "with defrauding investors in a Ponzi scheme involving bitcoin".

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