Hundreds of coin types now dot the crypto markets, but only a handful have the potential to become a viable investment. Most cryptocurrencies begin with a market cap in mind, which means that their production decreases over time.
Litecoin, Peer coin, Feather coin, Ethereum, and hundreds of other coins are all alt coins because they are not bitcoin. One of the advantages of bitcoin is that it can be stored offline on local hardware, such as a secure hard drive.
On the flip side, if a person loses access to the hardware that contains the bitcoins, the currency is gone forever. From 2011 to 2013, criminal traders made bitcoins famous by buying them in batches of millions of dollars, so they could move money outside the eyes of law enforcement and tax collectors.
Naive and savvy investors alike can lose hundreds or thousands of dollars to scams. Bitcoins and alt coins are controversial because they take the power of issuing money away from central banks and give it to the public.
Bitcoins can be used to purchase goods and services online with businesses that accept them or can be tucked away in the hope that their value increases over time. A wallet is a small personal database that is stored on a computer drive, smartphone, tablet, or in the cloud.
DESIGN/SCIENCE PHOTO LIBRARY / Getty Images Bitcoins are forgery-resistant because multiple computers, called nodes, on the network must confirm the validity of every transaction. It is so computationally intensive to create a bitcoin that it isn't financially worth it for counterfeiters to manipulate the system.
Bitcoins will stop being created when the total number reaches 21 billion coins, which is estimated to be sometime around the year 2040. Miners are paid for their accounting work by earning new bitcoins for the amount of resources they contribute to the network.
A bitcoin holds a simple data ledger file called a blockchain. Dong Winnie / Getty Images All bitcoin transactions are logged and made available in a public ledger, which ensures their authenticity and prevents fraud.
In practical terms, this means that every bitcoin transaction is digitally confirmed but is completely anonymous at the same time. So, although people cannot easily see the personal identity or the details of the transaction, they can see the verified financial history of a bitcoin wallet.
Servers (nodes) that support the network of miners Online exchanges that convert bitcoins into dollars Mining pools A desktop computer, if it works nonstop, might be able to solve one bitcoin problem in two to three days, however, it might take longer.
A small-scale miner with a single consumer-grade computer may spend more on electricity than they will earn mining bitcoins. Bitcoin mining is profitable only for those who run multiple computers with high-performance video processing cards and who join a group of miners to combine hardware power.
This prohibitive hardware requirement is one of the biggest security measures that deter people from trying to manipulate the bitcoin system. People who take reasonable precautions are safe from having their personal bitcoin caches stolen by hackers.
More than hacker intrusion, the real loss risk with bitcoin revolves around not backing up a wallet with a fail-safe copy. Go as the biggest example, the people running unregulated online exchanges that trade cash for bitcoins can be dishonest or incompetent.
This is similar to Fannie Mae and Freddie Mac investment banks going under because of human dishonesty and incompetence. Bitcoins have become a tool for contraband trade and money laundering because of the lack of government oversight.
Bitcoins are transferred through a peer-to-peer network between individuals, with no middleman bank to take a slice. Bitcoin wallets cannot be seized or frozen or audited by banks and law enforcement.
Bitcoin can be used to book hotels on Expedia, shop for furniture on Overstock and buy Xbox games. In addition, international payments are easy and cheap because bitcoins are not tied to any country or subject to regulation.
But security can be a concern: bitcoins worth tens of millions of dollars were stolen from Biting when it was hacked in 2016. People compete to “mine” bitcoins using computers to solve complex math puzzles.
Bitcoins are stored in a “digital wallet,” which exists either in the cloud or on a user’s computer. The wallet is a kind of virtual bank account that allows users to send or receive bitcoins, pay for goods or save their money.
That’s why it has become the currency of choice for people online buying drugs or other illicit activities. It is mostly unregulated, but some countries like Japan, China and Australia have begun weighing regulations.
BitcoinDenominationsPlural bitcoins Symbol (Unicode: U+20BFBITCOIN SIGN (HTML ₿)) Ticker symbol BTC, BT Precision10 8 Subunits 1 1000 millibitcoin 1 100000000 Satoshi DevelopmentOriginal author(s) Satoshi NakamotoWhite paper”Bitcoin: A Peer-to-Peer Electronic Cash System” Implementation(s)Bitcoin CoreInitial release0.1.0 / 9 January 2009 (12 years ago) (2009-01-09) The Latest release 0.21.0 / 15 January 2021 (10 days ago) (2021-01-15) Development statusActiveWebsite bitcoin.org LedgerLedger start3 January 2009 (12 years ago) (2009-01-03) Timestamping schemeProof-of-work (partial hash inversion) Hash functionSHA-256 Issuance scheduleDecentralized (block reward)Initially 50 per block, halved every 210,000 blocks Block reward6.25 Block time10 minutesBlock explorer www.blockchain.com/explorer Circulating supply18,355,100 (as of 1 May 2021 )Supply limit21,000,000 ^ The symbol was encoded in Unicode version 10.0 at position U+20BF BITCOIN SIGN in the Currency Symbols block in June 2017. Bitcoin has been criticized for its use in illegal transactions, the large amount of electricity used by miners, price volatility, and thefts from exchanges.
Some economists, including several Nobel laureates, have characterized it as a speculative bubble at various times. The domain name “bitcoin.org” was registered on 18 August 2008.
On 31 October 2008, a link to a paper authored by Satoshi Nakamoto titled Bitcoin: A Peer-to-Peer Electronic Cash System was posted to a cryptography mailing list. Nakamoto implemented the bitcoin software as open-source code and released it in January 2009.
Nakamoto's identity remains unknown. On 3 January 2009, the bitcoin network was created when Nakamoto mined the starting block of the chain, known as the genesis block.
Embedded in the Coinbase of this block was the text “The Times 03/Jan/2009 Chancellor on brink of second bailout for banks”. This note references a headline published by The Times and has been interpreted as both a timestamp and a comment on the instability caused by fractional-reserve banking.
The receiver of the first bitcoin transaction was cyberpunk Hal Finney, who had created the first system (Row) in 2004. Finney downloaded the bitcoin software on its release date, and on 12 January 2009 received ten bitcoins from Nakamoto.
In 2010, the first known commercial transaction using bitcoin occurred when programmer Laszlo Handed bought two Papa John's pizzas for 10,000. Blockchain analysts estimate that Nakamoto had mined about one million bitcoins before disappearing in 2010 when he handed the network alert key and control of the code repository over to Gavin Andersen.
This left opportunity for controversy to develop over the future development path of bitcoin, in contrast to the perceived authority of Nakamoto's contributions. After early proof-of-concept transactions, the first major users of bitcoin were black markets, such as Silk Road.
During its 30 months of existence, beginning in February 2011, Silk Road exclusively accepted bitcoins as payment, transacting 9.9 million in bitcoins, worth about $214 million. In 2011, the price started at $0.30 per bitcoin, growing to $5.27 for the year.
In 2012, bitcoin prices started at $5.27, growing to $13.30 for the year. By 9 January the price had risen to $7.38, but then crashed by 49% to $3.80 over the next 16 days.
The price then rose to $16.41 on 17 August, but fell by 57% to $7.10 over the next three days. On 1 November 2011, the reference implementation Bitcoin-Qt version 0.5.0 was released.
It introduced a front end that used the Qt user interface toolkit. The software previously used Berkeley DB for database management.
Developers switched to Level in release 0.8 in order to reduce blockchain synchronization time. The update to this release resulted in a minor blockchain fork on the 11 March 2013.
Seeding nodes through IRC was discontinued in version 0.8.2. From version 0.9.0 the software was renamed to Bitcoin Core.
Transaction fees were reduced again by a factor of ten as a means to encourage microtransactions. Although Bitcoin Core does not use OpenSSL for the operation of the network, the software did use OpenSSL for remote procedure calls.
Version 0.9.1 was released to remove the network's vulnerability to the Heart bleed bug. In 2013, prices started at $13.30 rising to $770 by 1 January 2014.
In March 2013 the blockchain temporarily split into two independent chains with different rules due to a bug in version 0.8 of the bitcoin software. The two blockchains operated simultaneously for six hours, each with its own version of the transaction history from the moment of the split.
Normal operation was restored when the majority of the network downgraded to version 0.7 of the bitcoin software, selecting the backwards-compatible version of the blockchain. As a result, this blockchain became the longest chain and could be accepted by all participants, regardless of their bitcoin software version.
Go exchange briefly halted bitcoin deposits and the price dropped by 23% to $37 before recovering to the previous level of approximately $48 in the following hours. The US Financial Crimes Enforcement Network (Fin CEN) established regulatory guidelines for “decentralized virtual currencies” such as bitcoin, classifying American bitcoin miners who sell their generated bitcoins as Money Service Businesses (MSB's), that are subject to registration or other legal obligations.
In April, exchanges Instant and Mt. Go experienced processing delays due to insufficient capacity resulting in the bitcoin price dropping from $266 to $76 before returning to $160 within six hours.
The bitcoin price rose to $259 on 10 April, but then crashed by 83% to $45 over the next three days. On 5 December 2013, the People's Bank of China prohibited Chinese financial institutions from using bitcoins.
Buying real-world goods with any virtual currency had been illegal in China since at least 2009. In 2014, prices started at $770 and fell to $314 for the year.
On 30 July 2014, the Wikimedia Foundation started accepting donations of bitcoin. In 2015, prices started at $314 and rose to $434 for the year.
In 2016, prices rose and climbed up to $998 by 1 January 2017. Release 0.10 of the software was made public on 16 February 2015.
It introduced a consensus library which gave programmers easy access to the rules governing consensus on the network. In version 0.11.2 developers added a new feature which allowed transactions to be made unspeakable until a specific time in the future.
Bitcoin Core 0.12.1 was released on April 15, 2016, and enabled multiple soft forks to occur concurrently. Around 100 contributors worked on Bitcoin Core 0.13.0 which was released on 23 August 2016.
In July 2016, the CheckSequenceVerify soft fork activated. In October 2016, Bitcoin Core's 0.13.1 release featured the Legit soft fork that included a scaling improvement aiming to optimize the bitcoin block size.
The patch which was originally finalized in April, and 35 developers were engaged to deploy it. This release featured Segregated Witness (Legit) which aimed to place downward pressure on transaction fees as well as increase the maximum transaction capacity of the network.
Legit prevents various forms of transaction malleability. On 15 July 2017, the controversial Segregated Witness software upgrade was approved (“locked-in”).
Legit was intended to support the Lightning Network as well as improve scalability. Legit was subsequently activated on the network on 24 August 2017.
The bitcoin price rose almost 50% in the week following Legit's approval. Supporters of large blocks who were dissatisfied with the activation of Legit forked the software on 1 August 2017 to create Bitcoin Cash.
Prices started at $998 in 2017 and rose to $13,412.44 on 1 January 2018, after reaching its all-time high of $19,783.06 on 17 December 2017. China banned trading in bitcoin, with first steps taken in September 2017, and a complete ban that started on 1 February 2018.
Bitcoin prices then fell from $9,052 to $6,914 on 5 February 2018. The percentage of bitcoin trading in the Chinese reminds fell from over 90% in September 2017 to less than 1% in June 2018.
Bitcoin prices were negatively affected by several hacks or thefts from cryptocurrency exchanges, including thefts from Coin check in January 2018, Bi thumb in June, and Bangor in July. For the first six months of 2018, $761 million worth of cryptocurrencies was reported stolen from exchanges.
Bitcoin's price was affected even though other cryptocurrencies were stolen at Conrail and Bangor as investors worried about the security of cryptocurrency exchanges. In September 2019 the Intercontinental Exchange (the owner of the NYSE) began trading of bitcoin futures on its exchange called Back.
In February 2019, Canadian cryptocurrency exchange Quadriga Fintech Solutions failed with approximately $200 million missing. According to Cliometrics and Forbes, on 11 March 281,000 bitcoins were sold by owners who held them for only thirty days.
This compared to 4,131 bitcoins that had laid dormant for a year or more, indicating that the vast majority of the bitcoin volatility on that day was from recent buyers. During the week of 11 March 2021 as a result of the COVID-19 pandemic, cryptocurrency exchange Kraken experienced an 83% increase in the number of account sign ups over the week of bitcoin's price collapse, a result of buyers looking to capitalize on the low price.
On 13 March 2021, bitcoin fell below $4000 during a broad COVID-19 pandemic related market selloff, after trading above $10,000 in February 2020. In August 2020, MicroStrategy invested $250 million in bitcoin as a treasury reserve asset.
In October 2020, Square, Inc. put approximately 1% of their total assets ($50 million) in bitcoin. Alexander Minnie, founder of BTC-e, was convicted and sentenced to 5 years in prison for money laundering in France while refusing to testify during his trial.
In December 2020 Massachusetts Mutual Life Insurance Company announced it has purchased $100 million in bitcoin, or roughly 0.04% of its general investment account. Ticker symbols used to represent bitcoin are BTC and BT.
Small amounts of bitcoin used as alternative units are millibitcoin (MBC), and Satoshi (sat). Data structure of blocks in the ledger.
A network of communicating nodes running bitcoin software maintains the blockchain. :215–219 Transactions of the form payer X sends Y bitcoins to payee Z are broadcast to this network using readily available software applications.
Network nodes can validate transactions, add them to their copy of the ledger, and then broadcast these ledger additions to other nodes. To achieve independent verification of the chain of ownership each network node stores its own copy of the blockchain.
At varying intervals of time averaging to every 10 minutes, a new group of accepted transactions, called a block, is created, added to the blockchain, and quickly published to all nodes, without requiring central oversight. A conventional ledger records the transfers of actual bills or promissory notes that exist apart from it, but the blockchain is the only place that bitcoins can be said to exist in the form of unspent outputs of transactions.
Transactions are defined using a Forth -like scripting language. 5 Transactions consist of one or more inputs and one or more outputs.
When a user sends bitcoins, the user designates each address and the amount of bitcoin being sent to that address in an output. To prevent double spending, each input must refer to a previous unspent output in the blockchain.
Since transactions can have multiple outputs, users can send bitcoins to multiple recipients in one transaction. As in a cash transaction, the sum of inputs (coins used to pay) can exceed the intended sum of payments.
In such a case, an additional output is used, returning the change back to the payer. Miners may choose transactions based on the fee paid relative to their storage size, not the absolute amount of money paid as a fee.
These fees are generally measured in Satoshi per byte (sat/b). The size of transactions is dependent on the number of inputs used to create the transaction, and the number of outputs.
Simplified chain of ownership as illustrated in the bitcoin white paper. In practice, a transaction can have more than one input and more than one output.
Creating a bitcoin address requires nothing more than picking a random valid private key and computing the corresponding bitcoin address. But the reverse, computing the private key of a given bitcoin address, is practically unfeasible.
4 Users can tell others or make public a bitcoin address without compromising its corresponding private key. Moreover, the number of valid private keys is so vast that it is extremely unlikely someone will compute a key-pair that is already in use and has funds.
The vast number of valid private keys makes it unfeasible that brute force could be used to compromise a private key. To be able to spend their bitcoins, the owner must know the corresponding private key and digitally sign the transaction.
If the private key is lost, the bitcoin network will not recognize any other evidence of ownership; the coins are then unusable, and effectively lost. For example, in 2013 one user claimed to have lost 7,500 bitcoins, worth $7.5 million at the time, when he accidentally discarded a hard drive containing his private key.
About 20% of all bitcoins are believed to be lost -they would have had a market value of about $20 billion at July 2018 prices. Later amateurs mined bitcoins with specialized FPGA and ASIC chips.
The chips pictured have become obsolete due to increasing difficulty. Today, bitcoin mining companies dedicate facilities to housing and operating large amounts of high-performance mining hardware.
Mining is a record-keeping service done through the use of computer processing power. Miners keep the blockchain consistent, complete, and unalterable by repeatedly grouping newly broadcast transactions into a block, which is then broadcast to the network and verified by recipient nodes.
To be accepted by the rest of the network, a new block must contain a (Pow). The system used is based on Adam Back's 1997 anti- spam scheme, Hash cash.
The Pow requires miners to find a number called a nonce, such that when the block content is hashed along with the nonce, the result is numerically smaller than the network's difficulty target. 8 This proof is easy for any node in the network to verify, but extremely time-consuming to generate, as for a secure cryptographic hash, miners must try many nonce values (usually the sequence of tested values is the ascending natural numbers: 0, 1, 2, 3, ... :ch.
Every 2,016 blocks (approximately 14 days at roughly 10 min per block), the difficulty target is adjusted based on the network's recent performance, with the aim of keeping the average time between new blocks at ten minutes. In this way the system automatically adapts to the total amount of mining power on the network.
8 Between 1 March 2014 and 1 March 2015, the average number of nonce miners had to try before creating a new block increased from 16.4 quintillion to 200.5 quintillion. The proof-of-work system, alongside the chaining of blocks, makes modifications of the blockchain extremely hard, as an attacker must modify all subsequent blocks in order for the modifications of one block to be accepted.
Supply Total bitcoins in circulation. The successful miner finding the new block is allowed by the rest of the network to reward themselves with newly created bitcoins and transaction fees. As of 11 May 2021 , the reward amounted to 6.25 newly created bitcoins per block added to the blockchain, plus any transaction fees from payments processed by the block.
To claim the reward, a special transaction called a Coinbase is included with the processed payments. 8 All bitcoins in existence have been created in such Coinbase transactions.
The bitcoin protocol specifies that the reward for adding a block will be halved every 210,000 blocks (approximately every four years). Eventually, the reward will decrease to zero, and the limit of 21 million bitcoins will be reached c. 2140; the record keeping will then be rewarded solely by transaction fees.
In other words, Nakamoto set a monetary policy based on artificial scarcity at bitcoin's inception that the total number of bitcoins could never exceed 21 million. New bitcoins are created roughly every ten minutes and the rate at which they are generated drops by half about every four years until all will be in circulation.
Pooled mining 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.
A wallet stores the information necessary to transact bitcoins. While wallets are often described as a place to hold or store bitcoins, due to the nature of the system, bitcoins are inseparable from the blockchain transaction ledger.
A wallet is more correctly defined as something that “stores the digital credentials for your bitcoin holdings” and allows one to access (and spend) them. 1, glossary Bitcoin uses public-key cryptography, in which two cryptographic keys, one public and one private, are generated.
They have an inverse relationship in regard to restlessness and computational requirements. Full clients verify transactions directly by downloading a full copy of the blockchain (over 150 GB as of January 2018 ).
They are the most secure and reliable way of using the network, as trust in external parties is not required. Full clients check the validity of mined blocks, preventing them from transacting on a chain that breaks or alters network rules.
This makes lightweight clients much faster to set up and allows them to be used on low-power, low-bandwidth devices such as smartphones. When using a lightweight wallet, however, the user must trust the server to a certain degree, as it can report faulty values back to the user.
Lightweight clients follow the longest blockchain and do not ensure it is valid, requiring trust in miners. Third-party internet services called online wallets offer similar functionality but may be easier to use.
In this case, credentials to access funds are stored with the online wallet provider rather than on the user's hardware. As a result, the user must have complete trust in the online wallet provider.
A malicious provider or a breach in server security may cause entrusted bitcoins to be stolen. An example of such a security breach occurred with Mt.
A paper wallet with the address visible for adding or checking stored funds. The part of the page containing the private key is folded over and sealed.
A hardware wallet peripheral which processes bitcoin payments without exposing any credentials to the computer. Physical wallets store the credentials necessary to spend bitcoins offline and can be as simple as a paper printout of the private key: :ch.
A paper wallet is created with a key pair generated on a computer with no internet connection ; the private key is written or printed onto the paper and then erased from the computer. The paper wallet can then be stored in a safe physical location for later retrieval.
Bitcoins stored using a paper wallet are said to be in cold storage. Cameron and Tyler Winklevoss, the founders of the Gemini Trust Co. exchange, reported that they had cut their paper wallets into pieces and stored them in envelopes distributed to safe deposit boxes across the United States.
Through this system, the theft of one envelope would neither allow the thief to steal any bitcoins nor deprive the rightful owners of their access to them. Another type of physical wallet called a hardware wallet keeps credentials offline while facilitating transactions.
The hardware wallet acts as a computer peripheral and signs transactions as requested by the user, who must press a button on the wallet to confirm that they intended to make the transaction. Hardware wallets never expose their private keys, keeping bitcoins in cold storage even when used with computers that may be compromised by malware.
The first wallet program, simply named Bitcoin, and sometimes referred to as the Satoshi client, was released in 2009 by Satoshi Nakamoto as open-source software. In version 0.5 the client moved from the widgets user interface toolkit to Qt, and the whole bundle was referred to as Bitcoin-Qt.
After the release of version 0.9, the software bundle was renamed Bitcoin Core to distinguish itself from the underlying network. Bitcoin Cash has a larger block size limit and had an identical blockchain at the time of fork.
On 24 October 2017 another hard fork, Bitcoin Gold, was created. There is no central server; the bitcoin network is peer-to-peer.
There is no central storage; the bitcoin ledger is distributed. The ledger is public; anybody can store it on their computer.
1 There is no single administrator; the ledger is maintained by a network of equally privileged miners. 1 The additions to the ledger are maintained through competition.
They are issued as a reward for the creation of a new block. 1 Anybody can send a transaction to the network without needing any approval; the network merely confirms that the transaction is legitimate.
:220–222 Bitcoin miners join large mining pools to minimize the variance of their income. :215, 219–222 :3 Because transactions on the network are confirmed by miners, decentralization of the network requires that no single miner or mining pool obtains 51% of the hashing power, which would allow them to double-spend coins, prevent certain transactions from being verified and prevent other miners from earning income.
As of 2013 just six mining pools controlled 75% of overall bitcoin hashing power. In 2014 mining pool Hash.Io obtained 51% hashing power which raised significant controversies about the safety of the network.
The pool has voluntarily capped their hashing power at 39.99% and requested other pools to act responsibly for the benefit of the whole network. c. 2017 over 70% of the hashing power and 90% of transactions were operating from China.
According to researchers, other parts of the ecosystem are also “controlled by a small set of entities”, notably the maintenance of the client software, online wallets and simplified payment verification (SPV) clients. Owners of bitcoin addresses are not explicitly identified, but all transactions on the blockchain are public.
In addition, transactions can be linked to individuals and companies through “idioms of use” (e.g., transactions that spend coins from multiple inputs indicate that the inputs may have a common owner) and corroborating public transaction data with known information on owners of certain addresses. Additionally, bitcoin exchanges, where bitcoins are traded for traditional currencies, may be required by law to collect personal information.
To heighten financial privacy, a new bitcoin address can be generated for each transaction. Wallets and similar software technically handle all bitcoins as equivalent, establishing the basic level of frangibility.
Researchers have pointed out that the history of each bitcoin is registered and publicly available in the blockchain ledger, and that some users may refuse to accept bitcoins coming from controversial transactions, which would harm bitcoin's frangibility. Go froze accounts of users who deposited bitcoins that were known to have just been stolen.
The blocks in the blockchain were originally limited to 32 megabytes in size. The block size limit of one megabyte was introduced by Satoshi Nakamoto in 2010.
Eventually the block size limit of one megabyte created problems for transaction processing, such as increasing transaction fees and delayed processing of transactions. Andreas Antonopoulos has stated Lightning Network is a potential scaling solution and referred to lightning as a second layer routing network.
According to The New York Times, libertarians and anarchists were attracted to the idea. Early bitcoin supporter Roger Very said: “At first, almost everyone who got involved did so for philosophical reasons.
We saw bitcoin as a great idea, as a way to separate money from the state.” The Economist describes bitcoin as “a techno-anarchist project to create an online version of cash, a way for people to transact without the possibility of interference from malicious governments or banks”.
Economist Paul Krugman argues that cryptocurrencies like bitcoin are “something of a cult” based in “paranoid fantasies” of government power. External video The Declaration Of Bitcoin's Independence, BraveTheWorld, 4:38 Nigel Dodd argues in The Social Life of Bitcoin that the essence of the bitcoin ideology is to remove money from social, as well as governmental, control.
Dodd quotes a YouTube video, with Roger Very, Jeff Berwick, Charlie Shrew, Andreas Antonopoulos, Gavin Wood, Trace Meyer and other proponents of bitcoin reading The Declaration of Bitcoin's Independence. The declaration includes a message of crypto-anarchism with the words: “Bitcoin is inherently anti-establishment, anti-system, and anti-state.
David Columbia says that the ideas influencing bitcoin advocates emerge from right-wing extremist movements such as the Liberty Lobby and the John Birch Society and their anti-Central Bank rhetoric, or, more recently, Ron Paul and Tea Party -style libertarianism. Steve Bannon, who owns a “good stake” in bitcoin, considers it to be “disruptive populism.
It takes control back from central authorities. A 2014 study of Google Trends data found correlations between bitcoin-related searches and ones related to computer programming and illegal activity, but not libertarianism or investment topics.
Per some researchers, as of 2015 , bitcoin functions more than a payment system than as a currency. Economists define money as serving the following three purposes: a store of value, a medium of exchange, and a unit of account.
According to The Economist in 2014, bitcoin functions best as a medium of exchange. However, this is debated, and a 2018 assessment by The Economist stated that cryptocurrencies met none of these three criteria.
Yale economist Robert J. Schiller writes that bitcoin has potential as a unit of account for measuring the relative value of goods, as with Chile's Unidad de Fomento, but that “Bitcoin in its present form doesn't really solve any sensible economic problem”. According to research by Cambridge University, between 2.9 million and 5.8 million unique users used a cryptocurrency wallet in 2017, most of them for bitcoin.
The overwhelming majority of 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. 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 Grader. However, bitcoin continues to be used for large-item purchases on sites such as Overstock.com, and for cross-border payments to freelancers and other vendors.
Per researchers, “there is little sign of bitcoin use” in international remittances despite high fees charged by banks and Western Union who compete in this market. The South China Morning Post, however, mentions the use of bitcoin by Hong Kong workers to transfer money home.
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.
In September 2019 the Central Bank of Venezuela, at the request of PSA, ran tests to determine if bitcoin and ether could be held in central bank's reserves. The request was motivated by oil company's goal to pay its suppliers.
The Winklevoss twins have purchased bitcoin. In 2013, The Washington Post reported a claim that they owned 1% of all the bitcoins in existence at the time.
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.
Forbes named bitcoin the best investment of 2013. In 2014, Bloomberg named bitcoin one of its worst investments of the year.
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.
The price of bitcoins has gone through 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 a peak of US$1,242.
As of 16 November 2021, the closing price of bitcoin equals US$16,717. According to Mark T. Williams, as of 30 September 2014 , bitcoin has volatility seven times greater than gold, eight times greater than the S&P 500, and 18 times greater than the US dollar.
Hold is a meme created in reference to holding (as opposed to selling) during periods of volatility. Because of bitcoin's decentralized nature and its trading on online exchanges located in many countries, regulation of bitcoin has been difficult.
However, the use of bitcoin can be criminalized, and shutting down exchanges and the peer-to-peer economy in a given country would constitute a de facto ban. Regulations and bans that apply to bitcoin probably extend to similar cryptocurrency systems.
According to the Library of Congress, an “absolute ban” on trading or using cryptocurrencies applies in nine countries: Algeria, Bolivia, Egypt, Iraq, Morocco, Nepal, Pakistan, Vietnam, and the United Arab Emirates. An “implicit ban” applies in another 15 countries, which include Bahrain, Bangladesh, China, Colombia, the Dominican Republic, Indonesia, Kuwait, Lesotho, Lithuania, Macau, Oman, Qatar, Saudi Arabia and Taiwan.
An official investigation into bitcoin traders was reported in May 2018. The U.S. Justice Department launched an investigation into possible price manipulation, including the techniques of spoofing and wash trades.
The U.S. federal investigation was prompted by concerns of possible manipulation during futures settlement dates. The final settlement price of CME bitcoin futures is determined by prices on four exchanges, Bit stamp, Coinbase, Fitbit and Kraken.
Following the first delivery date in January 2018, the CME requested extensive detailed trading information but several of the exchanges refused to provide it and later provided only limited data. The Commodity Futures Trading Commission then subpoenaed the data from the exchanges.
Academic research published in the Journal of Monetary Economics concluded that price manipulation occurred during the Mt Go bitcoin theft and that the market remains vulnerable to manipulation. The history of hacks, fraud and theft involving bitcoin dates back to at least 2011.
Research by John M. Griffin and Amino Shams in 2018 suggests that trading associated with increases in the amount of the Tether cryptocurrency and associated trading at the Biting exchange account for about half of the price increase in bitcoin in late 2017. Van der Verde, CEO of both Biting and Tether, denied the claims of price manipulation: “Biting nor Tether is, or has ever, engaged in any sort of market or price manipulation.
Tether issuance cannot be used to prop up the price of bitcoin or any other coin/token on Biting.” The Bank for International Settlements summarized several criticisms of bitcoin in Chapter V of their 2018 annual report.
The criticisms include the lack of stability in bitcoin's price, the high energy consumption, high and variable transactions costs, the poor security and fraud at cryptocurrency exchanges, vulnerability to debasement (from forking), and the influence of miners. In 2015, The Economist described these criticisms as unfair, since bitcoin had been relatively stable during that year, and the shady image may have compelled users to overlook the capabilities of the blockchain technology.
Bitcoin price bubbles in 2011, 2013 and 2017Bitcoin, along with other cryptocurrencies, has been described as an economic bubble by at least eight Nobel Memorial Prize in Economic Sciences laureates at various times, including Robert Schiller on 1 March 2014, Joseph Stieglitz on 29 November 2017, and Richard Theiler on 21 December 2017. On 29 January 2018, a noted Keynesian economist Paul Krugman has described bitcoin as “a bubble wrapped in techno-mysticism inside a cocoon of libertarian ideology”, on 2 February 2018, professor Courier Robin of New York University has called bitcoin the “mother of all bubbles”, and on 27 April 2018, a University of Chicago economist James Hickman has compared it to the 17th-century tulip mania.
Bitcoin has been criticized for the amount of electricity consumed by mining. 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).
At the end of 2017, the global bitcoin mining activity was estimated to consume between one and four gigawatts of electricity. By 2018, bitcoin was estimated by Joule to use 2.55 GW, while Environmental Science & Technology estimated bitcoin to consume 3.572 GW (31.29 Two for the year).
In July 2019 BBC reported bitcoin consumes about 7 gigawatts, 0.2% of the global total, or equivalent to that of Switzerland. According to Politico, even the high-end estimates of bitcoin's total consumption levels amount to only about 6% of the total power consumed by the global banking sector, and even if bitcoin's consumption levels increased 100-fold from today's levels, bitcoin's consumption would still only amount to about 2% of global power consumption.
Concerns about bitcoin's environmental impact relate bitcoin's energy consumption to carbon emissions. The difficulty of translating the energy consumption into carbon emissions lies in the decentralized nature of bitcoin impeding the localization of miners to examine the electricity mix used.
However, other researchers criticized this analysis, arguing the underlying scenarios were inadequate, leading to overestimation. According to studies published in Joule and American Chemical Society in 2019, bitcoin's annual energy consumption results in annual carbon emission ranging from 17 to 22.9 MtCO2 which is comparable to the level of emissions of countries as Jordan and Sri Lanka or Kansas City.
International Energy Agency estimates bitcoin-related annual carbon emissions to be likely in a range from 10 to 20 MtCO2 and characterizes the predictions in Nature Climate Change as just “sensational predictions about bitcoin” echoing the warnings from late 1990s about Internet and its increasing energy consumption. Journalists, economists, investors, and the central bank of Estonia have voiced concerns that bitcoin is a Ponzi scheme.
In April 2013, Eric Poster, 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.” A July 2014 report by the World Bank concluded that bitcoin was not a deliberate Ponzi scheme.
:7 In June 2014, the Swiss Federal Council :21 examined the concerns that bitcoin might be a pyramid scheme; it concluded that, “Since in the case of bitcoin the typical promises of profits are lacking, it cannot be assumed that bitcoin is a pyramid scheme.” Several news outlets have asserted that the popularity of bitcoins hinges on the ability to use them to purchase illegal goods.
Nobel-prize winning economist Joseph Stieglitz says that bitcoin's anonymity encourages money laundering and other crimes. 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”.
Australian researchers have estimated that 25% of all bitcoin users and 44% of all bitcoin transactions are associated with illegal activity as of April 2017 . François R. Verde, Senior Economist at the Chicago Fed, described it as “an elegant solution to the problem of creating a digital currency”.
The MIT Digital Currency Initiative funds some development of Bitcoin Core. The project also maintains the cryptography library libsecp256k1.
Bitcoin Core includes a transaction verification engine and connects to the bitcoin network as a full node. Moreover, a cryptocurrency wallet, which can be used to transfer funds, is included by default.
It allows users to generate QR codes to receive payment. The software validates the entire blockchain, which includes all bitcoin transactions ever.
This distributed ledger which has reached more than 235 gigabytes in size as of Jan 2019, must be downloaded or synchronized before full participation of the client may occur. Although the complete blockchain is not needed all at once since it is possible to run in pruning mode.
A command line -based daemon with a JSON-RPC interface, bitcoin, is bundled with Bitcoin Core. It also provides access to test net, a global testing environment that imitates the bitcoin main network using an alternative blockchain where valueless “test bitcoins are used.
Retest or Regression Test Mode creates a private blockchain which is used as a local testing environment. Finally, bitcoin-cli, a simple program which allows users to send RPC commands to bitcoin, is also included.
Checkpoints which have been hard coded into the client are used only to prevent Denial of Service attacks against nodes which are initially syncing the chain. For this reason the checkpoints included are only as of several years ago.
A one megabyte block size limit was added in 2010 by Satoshi Nakamoto. This limited the maximum network capacity to about three transactions per second.
Since then, network capacity has been improved incrementally both through block size increases and improved wallet behavior. A network alert system was included by Satoshi Nakamoto as a way of informing users of important news regarding bitcoin.
It had become obsolete as news on bitcoin is now widely disseminated. Bitcoin Core includes a scripting language inspired by Forth that can define transactions and specify parameters.
ScriptPubKey is used to “lock” transactions based on a set of future conditions. ScriptSig is used to meet these conditions or “unlock” a transaction.
The original creator of the bitcoin client has described their approach to the software's authorship as it being written first to prove to themselves that the concept of purely peer-to-peer electronic cash was valid and that a paper with solutions could be written. The lead developer is Wladimir J. van der Loan, who took over the role on 8 April 2014.
Gavin Andersen was the former lead maintainer for the software client. Andersen left the role of lead developer for bitcoin to work on the strategic development of its technology.
Bitcoin Core in 2015 was central to a dispute with Bitcoin AT, a competing client that sought to increase the block size. Over a dozen different companies and industry groups fund the development of Bitcoin Core.
In Charles Stress 2013 science fiction novel, Neptune's Brood, the universal interstellar payment system is known as “bitcoin” and operates using cryptography. Stress later blogged that the reference was intentional, saying “I wrote Neptune's Brood in 2011.
Bitcoin was obscure back then, and I figured had just enough name recognition to be a useful term for an interstellar currency: it'd clue people in that it was a networked digital currency.” The 2014 documentary The Rise and Rise of Bitcoin portrays the diversity of motives behind the use of bitcoin by interviewing people who use it.
These include a computer programmer and a drug dealer. ^ The word bitcoin first occurred and was defined in the white paper published 31 October 2008; it is a compound of the words bit and coin.
No uniform convention for bitcoin capitalization exists; some sources use Bitcoin, capitalized, to refer to the technology and network and bitcoin, lowercase, to refer to the unit of account. The Wall Street Journal, The Chronicle of Higher Education, and the Oxford English Dictionary advocate use of lowercase bitcoin in all cases, a convention followed throughout this article.
^ As of 2014 , BTC is a commonly used code. It does not conform to ISO 4217 as BT is the country code of Bhutan, and ISO 4217 requires the first letter used in global commodities to be 'X'.
^ As of 2014 , BT, a code that conforms to ISO 4217 though is not officially part of it, is used by Bloomberg L.P., Commonly, and xe.com. The fact is that gold miners are rewarded for producing gold, while bitcoin miners are not rewarded for producing bitcoins ; they are rewarded for their record-keeping services.
8 ^ The private key can be printed as a series of letters and numbers, a seed phrase, or a 2D barcode. Usually, the public key or bitcoin address is also printed, so that a holder of a paper wallet can check or add funds without exposing the private key to a device.
^ Liquidity is estimated by a 365-day running sum of transaction outputs in USD. “Cracking the Bitcoin: Digging Into a $131M USD Virtual Currency”.
^ a b c d e “Statement of Jennifer Shaky Calvary, 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” (PDF). Financial Crimes Enforcement Network.
The Age of Cryptocurrency: How Bitcoin and Digital Money Are Challenging the Global Economic Order (1 ed.). 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.
^ “SEC.gov | INVESTOR ALERT: BITCOIN AND OTHER VIRTUAL CURRENCY-RELATED INVESTMENTS”. “Everything you need to know about Bitcoin, its mysterious origins, and the many alleged identities of its creator”.
^ “Here's The Problem with the New Theory That A Japanese Math Professor Is The Inventor of Bitcoin”. “Hal Finney received the first Bitcoin transaction.
“Meet Gavin Andersen, the most powerful person in the world of Bitcoin”. “A Solution To Bitcoin's Governance Problem”.
^ a b c d e f g h Trainer Böhm; Nicolas Christian; Benjamin Edelman; Tyler Moore (2015). “Bitcoin: Economics, Technology, and Governance”.
“Here's proof that this bitcoin crash is far from the worst the cryptocurrency has seen”. “Major glitches in Bitcoin network sparks sell-off; price temporarily falls 23%”.
“Technical problems cause Bitcoin to plummet from record high, Mt. “US regulator Bitcoin Exchanges Must Comply With Money Laundering Laws”.
Bitcoin miners must also register if they trade in their earnings for dollars. ^ “Application of Fin CEN's Regulations to Persons Administering, Exchanging, or Using Virtual Currencies” (PDF).
Go's Dollar Account, Accuse It Of Violating Money Transfer Regulations”. “Some basic rules for using 'bitcoin' as virtual money”.
“U.S. government makes its first-ever Bitcoin seizure”. “Winner of Bitcoin Auction, Tim Draper, Plans to Expand Currency's Use”.
^ “After Silk Road seizure, FBI Bitcoin wallet identified and pranked”. “The FBI's Plan For The Millions Worth Of Bitcoins Seized From Silk Road”.
^ “Baidu Stops Accepting Bitcoins After China Ban”. ^ “China bars use of virtual money for trading in real goods”.
Mastering Bitcoin: Programming the Open Blockchain (2nd ed.). BIP-68 and BIP-112 were activated in May 2016 as a soft fork upgrade to the consensus rules.
“Bitcoin Rallies Sharply After Vote Resolves Bitter Scaling Debate”. ^ “Bitcoin Hits a New Record High, But Stops Short of $20,000”.
^ “Bitcoin turns 10: The obscure technology that became a household name”. “Cryptocurrency exchange theft surges in first half of 2018: report”.
^ “Cryptocurrencies Tumble After $32 Million South Korea Exchange Hack”. “Billions in cryptocurrency wealth wiped out after hack”.
“The crypto world's latest hack sees Israel's Bangor lose $23.5M”. “NYSE Owner Launches Long-Awaited Bitcoin Futures”.
“Back Plans First Regulated Options Contracts on Bitcoin Futures”. “YouTube admits error over Bitcoin video purge”.
“Crypto CEO Dies Holding Only Passwords That Can Unlock Millions in Customer Coins”. ^ Del Castillo, Michael (19 March 2021).
“Square just bought $50 million in bitcoin”. ^ “PayPal says all users in US can now buy, hold and sell cryptocurrencies”.
^ “Bitcoin hits an all-time high of just under $20,000”. “BTC-e founder sentenced to five years in prison for laundering ransomware funds”.
“169-Year-Old MassMutual Invests $100 Million in Bitcoin”. ^ “Canton Zug to accept cryptocurrencies for tax payment beginning in 2021”.
^ “Canton Zug akzeptiert Kryptowährungen BEI Steven” (in German). “Bitcoin Ticker Available On Bloomberg Terminal For Employees”.
^ a b c d e Joshua A. Roll; Ian C. Davey; Edward W. Felted (11–12 June 2013). The Twelfth Workshop on the Economics of Information Security (WEI 2013).
A transaction fee is like a tip or gratuity left for the miner. ^ “Man Throws Away 7,500 Bitcoins, Now Worth $7.5 Million”.
^ “Bitcoin mania is hurting PC gamers by pushing up GPU prices”. ^ “Cryptocurrency mining operation launched by Iron Bridge Resources”.
“Bitcoin and Beyond: The Possibilities and Pitfalls of Virtual Currencies” (PDF). Federal Reserve Bank of St. Louis.
“On the Origins and Variations of Blockchain Technologies”. “Difficulty History” (The ratio of all hashes over valid hashes is D × 4,295,032,833, where D is the published “Difficulty” figure.).
“Understanding the blockchain hype: Why much of it is nothing more than snake oil and spin”. “2014 Outlook: Bitcoin Mining Chips, a High-Tech Arms Race”.
^ Ritchie S. King; Sam Williams; David Sinofsky (17 December 2013). “By reading this article, you're mining bitcoins ".
“On the Privacy Provisions of Bloom Filters in Lightweight Bitcoin Clients” (PDF). Archived (PDF) from the original on 5 October 2016.
“Quadriga's late founder used to store clients' Bitcoin passwords on paper, so they wouldn't get lost”. “Cassius, maker of shiny physical bitcoins, shut down by Treasury Department”.
^ a b c d e Shnen, Elias; Nippon, Matthew J.; Perelman, Howard (15 April 2016). “How to send bitcoin to a hardware wallet”.
“The Bitcoin Schism Shows the Genius of Open Source”. “Ethereum co-founder Dr Gavin Wood and company release Parity Bitcoin”.
^ Scorch, Florian; Schumann, Bjorn (2016). “Bitcoin and Beyond: A Technical Survey on Decentralized Digital Currencies”.
2015 IEEE/ACID 16th International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing (SNP). Info & IEEE Computer Society.
“Popular Bitcoin Mining Pool Promises To Restrict Its Compute Power To Prevent Feared '51%' Fiasco”. “China Plans to Ban Cryptocurrency Mining in Renewed Clampdown”.
While China was once home to about 70 percent of Bitcoin mining and 90 percent of trades, authorities have waged a nearly two-year campaign to shrink the crypto industry amid concerns over speculative bubbles, fraud and wasteful energy consumption. “Mapping the Bitcoin Economy Could Reveal Users' Identities”.
“How Bitcoin lets you spy on careless companies”. ^ Ben-Sasson, Eli; Chaise, Alessandro; German, Christina; Green, Matthew; Years, Ian; Former, Era; Via, Madras (2014).
Archived (PDF) from the original on 26 June 2018. “Leaderless Bitcoin Struggles to Make Its Most Crucial Decision”.
2 Lord North Street, Westminster, London SHIP 3LB: The institute of economic affairs. CS1 main: location (link) ^ European Central Bank (October 2012).
Archived (PDF) from the original on 6 November 2012. Lack of adoption and loads of volatility mean that cryptocurrencies satisfy none of those criteria.
^ a b Matthew Graham Wilson & Aaron Velocity (November 2014). “Characteristics of Bitcoin Users: An Analysis of Google Search Data”.
“In Search of a Stable Electronic Currency”. “Atlanta-based Betray hooks up with PayPal to expand bitcoin adoption”.
“Bitcoin Acceptance Among Retailers Is Low and Getting Lower”. “Bitcoin's Use in Commerce Keeps Falling Even as Volatility Eases”.
^ “Bitcoin firms dumped by National Australia Bank as 'too risky “. “HSBC severs links with firm behind Bitcoin fund”.
^ “CCC investigating why banks are closing bitcoin companies' accounts”. ^ “Bitcoin futures surge in first day of trading”.
^ “MicroStrategy Buys $50 Million Worth Of Bitcoin, Topping Up Holdings To $766M”. ^ “MicroStrategy buys $250M in Bitcoin as CEO says it's superior to cash”.
“Silk Road's legacy 30,000 bitcoin sold at auction to mystery buyers”. “Digital Currencies: Principles, Trends, Opportunities, and Risks”.
“When Governments Take Your Money, Bitcoin Looks Wonderful”. ^ “Bitcoin prices remain below $600 amid bearish chart signals”.
^ “China May Be Gearing Up to Ban Bitcoin”. The decentralized nature of bitcoin is such that it is impossible to “ban” the cryptocurrency, but if you shut down exchanges and the peer-to-peer economy running on bitcoin, it's a de facto ban.
Archived (PDF) from the original on 14 August 2018. ^ “Iran: New Crypto Law Requires Selling Bitcoin Directly to Central Bank to Fund Imports”.
^ “Iran Has a Bitcoin Strategy to Beat Trump”. ^ “Customer Advisory: Use Caution When Buying Digital Coins or Tokens” (PDF).
Archived (PDF) from the original on 17 July 2018. ^ “Investor Alert: Bitcoin and Other Virtual Currency-related Investments”.
“Bitcoin investigation to focus on British traders, US officials examine manipulation of cryptocurrency prices”. “Bitcoin slips again on reports of US DoJ investigation”.
“Bitcoin value gyrates amid report of Department of Justice manipulation investigation”. Rubin, Gabriel T.; Michael's, Dave; Osipovich, Alexander (8 June 2018).
“U.S. regulators demand trading data from bitcoin exchanges in manipulation probe”. Note:this is a short open access version of a Wall Street Journal article Rubin, Gabriel T.; Michael's, Dave; Osipovich, Alexander (8 June 2018).
“U.S. regulators demand trading data from bitcoin exchanges in manipulation probe”. “State regulators unveil nationwide crackdown on suspicious cryptocurrency investment schemes”.
“Bitcoin's astronomical rise last year was buoyed by market manipulation, researchers say”. “Cryptocurrencies like bitcoin cannot replace money, says Bank for International Settlements”.
“Bitcoin 'Ought to Be Outlawed,' Nobel Prize Winner Stieglitz Says”. ^ “Economics Nobel Prize winner, Richard Theiler: “The market that looks most like a bubble to me is Bitcoin and its brethren ".
' Only good for drug dealers': More Nobel Prize winners snub bitcoin”. ^ “Bitcoin biggest bubble in history, says economist who predicted 2008 crash”.
“Greenspan Says Bitcoin a Bubble Without Intrinsic Currency Value”. “George Soros: Bitcoin is a bubble, Trump is a 'danger to the world “.
^ Mooney, Chris; Hudson, Steven (19 December 2017). Retrieved 11 January 2018. Several experts told The Washington Post that bitcoin probably uses as much as 1 to 4 gigawatts, or a billion watts, of electricity, roughly the output of one to three nuclear reactors.
“Can renewable power offset bitcoin's massive energy demands?” “Chinese bitcoin miners eye sites in energy-rich Canada”.
^ “Bitcoin is literally ruining the earth, claim experts”. ^ “The Hard Math Behind Bitcoin's Global Warming Problem”.
“Bitcoin emissions alone could push global warming above 2 °C”. ^ a b Still, Christian; Karen, Lena; Gallersdörfer, Ulrich (2019).
“Implausible projections overestimate near-term Bitcoin CO 2 emissions”. ^ Dietmar, Lars; Praktiknjo, Aaron (2019).
Archived (PDF) from the original on 31 October 2014. ^ “Federal Council report on virtual currencies in response to the Schwa ab (13.3687) and Label (13.4070) postulates” (PDF).
“How Russian Spies Hid Behind Bitcoin in Hacking Campaign”. “Silk Road: the online drug marketplace that officials seem powerless to stop”.
“Stieglitz, Robin and Logoff lead joint attack on bitcoin”. ^ Foley, Sean; Karl sen, Jonathan R.; Putting, Talks J.
“Sex, drugs, and bitcoin: How much illegal activity is financed through cryptocurrencies?” University of Oxford Faculty of Law.
“Sex, Drugs, and Bitcoin: How Much Illegal Activity Is Financed Through Cryptocurrencies?”. Social Science Research Network.
“St. Louis Fed Economist: Bitcoin Could Be A Good Threat To Central Banks”. 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. “PayPal president David Marcus: Bitcoin is good, NFC is bad”.
Mastering Bitcoin: Programming the Open Blockchain (2nd ed.). Bitcoin Core is the reference implementation of the bitcoin system, meaning that it is the authoritative reference on how each part of the technology should be implemented.
Bitcoin Core implements all aspects of bitcoin, including wallets, a transaction and block validation engine, and a full network node in the peer-to-peer bitcoin network. Mastering Bitcoin: Unlocking Digital Cryptocurrencies.
^ “MIT Announces $900,000 Bitcoin Developer Fund”. “Leaderless Bitcoin Struggles to Make Its Most Crucial Decision”.