Bitcoin is known as the very first decentralized digital currency, they’re basically coins that can send through the Internet. 2009 was the year where bitcoin was born. The creator’s name is unknown, however the alias Satoshi Nakamoto was given to this person. Bitcoin accounts cannot be frozen, prerequisites to open them don’t exist, same for limits on bitcoin usd .
Advantages of Bitcoin
Bitcoin transactions are made directly from person to person trough the internet. There’s no need of a bank or clearinghouse to act as the middle man. Thanks to that, the transaction fees are way too much lower, they can be used in all the countries around the world. Every day more merchants are starting to accept them. You can buy anything you want with them. How Bitcoin works. You should explore bitcoin mining. It’s possible to exchange dollars, euros or other currencies to bitcoin. You can buy and sell as it were any other country currency. In order to keep your bitcoins, you have to store them in something called wallets. These wallet are located in your pc, mobile device or in third party websites. Sending bitcoins is very simple. It’s as simple as sending an email. Invest in bitcoin to get great returns.
You can purchase practically anything with bitcoins.Bitcoin Anonymity.When doing a bitcoin transaction, there’s no need to provide the real name of the person. Each one of the bitcoin transactions are recorded is what is known as a public log. This log contains only wallet IDs and not people’s names. so basically each transaction is private. People can buy and sell things without being tracked.
Bitcoin innovation. Bitcoin established a whole new way of innovation. The bitcoin software is all open source, this means anyone can review it. A nowadays fact is that bitcoin is transforming world’s finances similar to how web changed everything about publishing. The concept is brilliant. When everyone has access to the whole bitcoin global market, new ideas appear. Transaction fees reductions is a fact of bitcoin. Accepting bitcoins cost anything, also they’re very easy to setup. Charge backs don’t exist. The bitcoin community will generate additional businesses of all kinds.
What Makes bitcoin usd So Interesting?
A diagram of a bitcoin transfer
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". The protocol was designed in 2008 and released in 2009 as open source software by Satoshi Nakamoto, the name or pseudonym of the original developer/developer group.
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.
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.
GPU-based mining rig, 2012 Lancelot FPGA-based mining board, 2013
To form a distributed timestamp server as a peer-to-peer network, bitcoin uses a proof-of-work system. The work in this system is what is often referred to as bitcoin mining. The signature is discovered rather than provided by knowledge. This process is energy intensive. Electricity can consume more than 90% of operating costs for miners. A data center in China, planned mostly for bitcoin mining, is expected to require up to 135 MW of power.
The rule of requiring a proof-of-work to provide the signature for 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.
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.
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 CPUs, high-end GPUs common in many gaming computers, FPGAs and ASICs all have been used, each reducing the profitability of the less-specialized technology. Bitcoin-specific ASICs are now available. As bitcoins become more difficult to mine, computer hardware manufacturing companies have seen an increase in sales of high-end 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.
Bitcoin data centers prefer to keep a low profile, are dispersed around the world and tend to cluster around the availability of cheap electricity.
A mining farm in Iceland
In 2013, Mark Gimein estimated electricity use 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).
Journalist Matt O'Brien opined that it is not obvious whether bitcoin is lowering transaction costs, since the costs are transformed into pollution costs, which he characterizes as "environmental spillovers on everyone else, or what economists call negative externalities."
To lower the costs, 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.
Avalon ASIC-based mining machine ASICMINER ASIC-based USB mining device
A rough overview of the process to mine bitcoins is:
- New transactions are broadcast to all nodes.
- Each miner node collects new transactions into a block.
- Each miner node works on finding a proof-of-work code for its block.
- When a node finds a proof-of-work, it broadcasts the block to all nodes.
- Receiving nodes validate the transactions it holds and accept only if all are valid.
- Nodes express their acceptance by moving to work on the next block, incorporating the hash of the accepted block.
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. This halving process is programmed to continue for 64 times before new coin creation ceases.
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 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.
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 haven't been previously spent.:4
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.
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 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.
Main article: Online transaction processing
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 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.
While it is possible to store any digital file in the blockchain, the larger the transaction size, the larger any associated fees become. Various items have been embedded, including URLs to child pornography, an ASCII art image of Ben Bernanke, material from the Wikileaks cables, prayers from bitcoin miners, and the original bitcoin whitepaper.
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."
Main article: Darknet market
A CMU 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 services, 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 faces a life sentence.
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 isn't 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.[better source needed] Furthermore, hyperlinks to child porn websites have been added to the blockchain as arbitrary data can be included when a transaction is made.
Some malware can steal private keys for bitcoin wallets allowing the bitcoins themselves to be stolen. The most common type searches computers for cryptocurrency wallets to upload to a remote server where they can be cracked and their coins stolen. Many of these also log keystrokes to record passwords, often avoiding the need to crack the keys. A different approach detects when a bitcoin address is copied to a clipboard and quickly replaces it with a different address, tricking people into sending bitcoins to the wrong address. This method is effective because bitcoin transactions are irreversible.:57
One virus, spread through the Pony botnet, was reported in February 2014 to have stolen up to $220,000 in cryptocurrencies including bitcoins from 85 wallets. Security company Trustwave, which tracked the malware, reports that its latest version was able to steal 30 types of digital currency.
A type of Mac malware active in August 2013, Bitvanity posed as a vanity wallet address generator and stole addresses and private keys from other bitcoin client software. A different trojan for macOS, called CoinThief was reported in February 2014 to be responsible for multiple bitcoin thefts. The software was hidden in versions of some cryptocurrency apps on Download.com and MacUpdate.
Some ransomware demand payment in bitcoin. One program called CryptoLocker, typically spread through legitimate-looking email attachments, encrypts the hard drive of an infected computer, then displays a countdown timer and demands a ransom, usually two bitcoins, to decrypt it. Massachusetts police said they paid a 2 bitcoin ransom in November 2013, worth more than $1,300 at the time, to decrypt one of their hard drives. Linkup, a combination ransomware and bitcoin mining program that surfaced in February 2014, disables internet access and demands credit card information to restore it, while secretly mining bitcoins. Bitcoin is currently being used as the ransom medium of choice in the WannaCry ransomware hack hitting many buildings in Asia and Europe.
In June 2011, Symantec warned about the possibility that botnets could mine covertly for bitcoins. Malware used the parallel processing capabilities of GPUs built into many modern video cards. Although the average PC with an integrated graphics processor is virtually useless for bitcoin mining, tens of thousands of PCs laden with mining malware could produce some results.
In mid-August 2011, bitcoin mining botnets were detected, and less than three months later, bitcoin mining trojans had infected Mac OS X.
In April 2013, electronic sports organization E-Sports Entertainment was accused of hijacking 14,000 computers to mine bitcoins; the company later settled the case with the State of New Jersey.
German police arrested two people in December 2013 who customized existing botnet software to perform bitcoin mining, which police said had been used to mine at least $950,000 worth of bitcoins.
For four days in December 2013 and January 2014, Yahoo! Europe hosted an ad containing bitcoin mining malware that infected an estimated two million computers. The software, called Sefnit, was first detected in mid-2013 and has been bundled with many software packages. Microsoft has been removing the malware through its Microsoft Security Essentials and other security software.
Several reports of employees or students using university or research computers to mine bitcoins have been published.
Bitcoins may not be ideal for money laundering, because all transactions are public. Authorities, including the European Banking Authority the FBI, 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". A report by UK's Treasury and Home Office named "UK national risk assessment of money laundering and terrorist financing" (2015 October) found that, of the twelve methods examined in the report, bitcoin carries the lowest risk of being used for money laundering, with the most common money laundering method being the banks.
In a Ponzi scheme that utilized bitcoins, The Bitcoin Savings and Trust promised investors up to 7 percent weekly interest, and raised at least 700,000 bitcoins from 2011 to 2012. 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". In September 2014 the judge fined Bitcoin Savings & Trust and its owner $40 million for operating a bitcoin Ponzi scheme.
There have been many cases of bitcoin theft. One way this is accomplished involves a third party accessing the private key to a victim's bitcoin address, or of an online wallet. If the private key is stolen, all the bitcoins from the compromised address can be transferred. In that case, the network does not have any provisions to identify the thief, block further transactions of those stolen bitcoins, or return them to the legitimate owner.
Theft also occurs at sites where bitcoins are used to purchase illicit goods. In late November 2013, an estimated $100 million in bitcoins were allegedly stolen from the online illicit goods marketplace Sheep Marketplace, which immediately closed. Users tracked the coins as they were processed and converted to cash, but no funds were recovered and no culprits identified. A different black market, Silk Road 2, stated that during a February 2014 hack, bitcoins valued at $2.7 million were taken from escrow accounts.
Sites where users exchange bitcoins for cash or store them in "wallets" are also targets for theft. Inputs.io, an Australian wallet service, was hacked twice in October 2013 and lost more than $1 million in bitcoins. In late February 2014 Mt. Gox, one of the largest virtual currency exchanges, filed for bankruptcy in Tokyo amid reports that bitcoins worth $350 million had been stolen. Flexcoin, a bitcoin storage specialist based in Alberta, Canada, shut down on March 2014 after saying it discovered a theft of about $650,000 in bitcoins. Poloniex, a digital currency exchange, reported on March 2014 that it lost bitcoins valued at around $50,000. In January 2015 UK-based bitstamp, the third busiest bitcoin exchange globally, was hacked and $5 million in bitcoins were stolen. February 2015 saw a Chinese exchange named BTER lose bitcoins worth nearly $2 million to hackers.
A major bitcoin exchange, Bitfinex, was hacked and nearly 120,000 bitcoins (around $60m) was stolen in 2016. Bitfinex was forced to suspend its trading. The theft is the second largest bitcoin heist ever, dwarfed only by Mt. Gox theft in 2014. According to Forbes, "All of Bitfinex's customers,... will stand to lose money. The company has announced a haircut of 36.067% across the board."
Thefts have raised safety concerns. Charles Hayter, founder of digital currency comparison website CryptoCompare said, "It’s a reminder of the fragility of the infrastructure in such a nascent industry." According to the hearing of U.S. House of Representatives Committee on Small Business in April 2, 2014, "these vendors lack regulatory oversight, minimum capital standards and don't provide consumer protection against loss or theft."
(Redirected from History of Bitcoin)
Number of bitcoin transactions per month (logarithmic scale)
Bitcoin is a cryptocurrency, a digital asset designed to work as a medium of exchange that uses cryptography to control its creation and management, rather than relying on central authorities. The presumed pseudonymous Satoshi Nakamoto integrated many existing ideas from the cypherpunk community when creating bitcoin.
Prior to the release of bitcoin there were a number of digital cash technologies starting with the issuer based ecash protocols of David Chaum  and Stefan Brands. Adam Back developed hashcash, a proof-of-work scheme for spam control. The first proposals for distributed digital scarcity based cryptocurrencies were Wei Dai's b-money and Nick Szabo's bit gold.Hal Finney developed reusable proof of work (RPOW) using hashcash as its proof of work algorithm.
In the bit gold proposal which proposed a collectible market based mechanism for inflation control, Nick Szabo also investigated some additional enabling aspects including a Byzantine fault-tolerant asset registry to store and transfer the chained proof-of-work solutions.
There has been much speculation as to the identity of Satoshi Nakamoto with suspects including Wei Dai, Hal Finney and accompanying denials. The possibility that Satoshi Nakamoto was a computer collective in the European financial sector has also been bruited.
In November 2008, a paper was posted to a cryptography mailing list under the name Satoshi Nakamoto titled Bitcoin: A Peer-to-Peer Electronic Cash System. This paper detailed methods of using a peer-to-peer network to generate what was described as "a system for electronic transactions without relying on trust". In January 2009, the bitcoin network came into existence with the release of the first open source bitcoin client and the issuance of the first bitcoins, with Satoshi Nakamoto mining the first block of bitcoins ever (known as the genesis block), which had a reward of 50 bitcoins.
One of the first supporters, adopters, contributor to bitcoin and receiver of the first bitcoin transaction was programmer Hal Finney. Finney downloaded the bitcoin software the day it was released, and received 10 bitcoins from Nakamoto in the world's first bitcoin transaction. Other early supporters were Wei Dai, creator of bitcoin predecessor b-money, and Nick Szabo, creator of bitcoin predecessor bit gold.
In the early days, Nakamoto is estimated to have mined 1 million bitcoins. Before disappearing from any involvement in bitcoin, Nakamoto in a sense handed over the reins to developer Gavin Andresen, who then became the bitcoin lead developer at the Bitcoin Foundation, the 'anarchic' bitcoin community's closest thing to an official public face.
The value of the first bitcoin transactions were negotiated by individuals on the bitcointalk forums with one notable transaction of 10,000 BTC used to indirectly purchase two pizzas delivered by Papa John's.
On 6 August 2010, a major vulnerability in the bitcoin protocol was spotted. Transactions weren't properly verified before they were included in the transaction log or blockchain, which let users bypass bitcoin's economic restrictions and create an indefinite number of bitcoins. On 15 August, the vulnerability was exploited; over 184 billion bitcoins were generated in a transaction, and sent to two addresses on the network. Within hours, the transaction was spotted and erased from the transaction log after the bug was fixed and the network forked to an updated version of the bitcoin protocol. This was the only major security flaw found and exploited in bitcoin's history.
Based on bitcoin's open source code, other cryptocurrencies started to emerge.
The Electronic Frontier Foundation, a non-profit group, started accepting bitcoins in January 2011, stopped accepting them in June 2011, and began again in May 2013.
In June 2011 Wikileaks and other organizations began to accept bitcoins for donations. The Electronic Frontier Foundation began, and then temporarily suspended, bitcoin acceptance, citing concerns about a lack of legal precedent about new currency systems. The EFF's decision was reversed on 17 May 2013 when they resumed accepting bitcoin.
On 22 March 2011 WeUseCoins published the first viral video  which has had over 6.4 million views. In September 2011 Vitalik Buterin co-founded Bitcoin Magazine. On 23 December 2011, Douglas Feigelson of BitBills filed a patent application for "Creating And Using Digital Currency" with the United States Patent and Trademark Office, an action which was contested based on prior art in June 2013.
In January 2012, bitcoin was featured as the main subject within a fictionalized trial on the CBS legal drama The Good Wife in the third-season episode "Bitcoin for Dummies". The host of CNBC's Mad Money, Jim Cramer, played himself in a courtroom scene where he testifies that he doesn't consider bitcoin a true currency, saying "There's no central bank to regulate it; it's digital and functions completely peer to peer".
In September 2012, the Bitcoin Foundation was launched to "accelerate the global growth of bitcoin through standardization, protection, and promotion of the open source protocol". The founders were Gavin Andresen, Jon Matonis, Patrick Murck, Charlie Shrem, and Peter Vessenes.
In October 2012, BitPay reported having over 1,000 merchants accepting bitcoin under its payment processing service. In November 2012, WordPress had started accepting bitcoins.
In February 2013 the bitcoin-based payment processor Coinbase reported selling US$1 million worth of bitcoins in a single month at over $22 per bitcoin. The Internet Archive announced that it was ready to accept donations as bitcoins and that it intends to give employees the option to receive portions of their salaries in bitcoin currency.
In March the bitcoin transaction log called the blockchain temporarily split into two independent chains with differing rules on how transactions were accepted. For six hours two bitcoin networks operated at the same time, each with its own version of the transaction history. The core developers called for a temporary halt to transactions, sparking a sharp sell-off. Normal operation was restored when the majority of the network downgraded to version 0.7 of the bitcoin software. The Mt. Gox exchange briefly halted bitcoin deposits and the exchange rate briefly dipped by 23% to $37 as the event occurred before recovering to previous level of approximately $48 in the following hours. In the US, the Financial Crimes Enforcement Network (FinCEN) established regulatory guidelines for "decentralized virtual currencies" such as bitcoin, classifying American "bitcoin miners" who sell their generated bitcoins as Money Service Businesses (or MSBs), that may be subject to registration and other legal obligations.
In April, payment processors BitInstant and Mt. Gox experienced processing delays due to insufficient capacity resulting in the bitcoin exchange rate dropping from $266 to $76 before returning to $160 within six hours. Bitcoin gained greater recognition when services such as OkCupid and Foodler began accepting it for payment.
On 15 May 2013, the US authorities seized accounts associated with Mt. Gox after discovering that it had not registered as a money transmitter with FinCEN in the US.
On 17 May 2013, it was reported that BitInstant processed approximately 30 percent of the money going into and out of bitcoin, and in April alone facilitated 30,000 transactions,
On 23 June 2013, it was reported that the US Drug Enforcement Administration listed 11.02 bitcoins as a seized asset in a United States Department of Justice seizure notice pursuant to 21 U.S.C. § 881. It is the first time a government agency has claimed to have seized bitcoin.
In July 2013 a project began in Kenya linking bitcoin with M-Pesa, a popular mobile payments system, in an experiment designed to spur innovative payments in Africa. During the same month the Foreign Exchange Administration and Policy Department in Thailand stated that bitcoin lacks any legal framework and would therefore be illegal, which effectively banned trading on bitcoin exchanges in the country. According to Vitalik Buterin, a writer for Bitcoin Magazine, "bitcoin's fate in Thailand may give the electronic currency more credibility in some circles", but he was concerned it didn't bode well for bitcoin in China.
On 6 August 2013, Federal Judge Amos Mazzant of the Eastern District of Texas of the Fifth Circuit ruled that bitcoins are "a currency or a form of money" (specifically securities as defined by Federal Securities Laws), and as such were subject to the court's jurisdiction, and Germany's Finance Ministry subsumed bitcoins under the term "unit of account"—a financial instrument—though not as e-money or a functional currency, a classification nonetheless having legal and tax implications.
In October 2013, the FBI seized roughly 26,000 BTC from website Silk Road during the arrest of alleged owner Ross William Ulbricht. Two companies, Robocoin and Bitcoiniacs launched the world's first bitcoin ATM on 29 October 2013 in Vancouver, BC, Canada, allowing clients to sell or purchase bitcoin currency at a downtown coffee shop. Chinese internet giant Baidu had allowed clients of website security services to pay with bitcoins.
In November 2013, the University of Nicosia announced that it would be accepting bitcoin as payment for tuition fees, with the university's chief financial officer calling it the "gold of tomorrow". During November 2013, the China-based bitcoin exchange BTC China overtook the Japan-based Mt. Gox and the Europe-based Bitstamp to become the largest bitcoin trading exchange by trade volume.
In December 2013, Overstock.com announced plans to accept bitcoin in the second half of 2014. On 5 December 2013, the People's Bank of China prohibited Chinese financial institutions from using bitcoins. After the announcement, the value of bitcoins dropped, and Baidu no longer accepted bitcoins for certain services. Buying real-world goods with any virtual currency has been illegal in China since at least 2009.
In January 2014, Zynga announced it was testing bitcoin for purchasing in-game assets in seven of its games. That same month, The D Las Vegas Casino Hotel and Golden Gate Hotel & Casino properties in downtown Las Vegas announced they would also begin accepting bitcoin, according to an article by USA Today. The article also stated the currency would be accepted in five locations, including the front desk and certain restaurants. The network rate exceeded 10 petahash/sec.TigerDirect and Overstock.com started accepting bitcoin.
In early February 2014, one of the largest bitcoin exchanges, Mt. Gox, suspended withdrawals citing technical issues. By the end of the month, Mt. Gox had filed for bankruptcy protection in Japan amid reports that 744,000 bitcoins had been stolen. Months before the filing, the popularity of Mt. Gox had waned as users experienced difficulties withdrawing funds.
In June 2014 the network exceeded 100 petahash/sec. On 18 June 2014, it was announced that bitcoin payment service provider BitPay would become the new sponsor of St. Petersburg Bowl under a two-year deal, renamed the Bitcoin St. Petersburg Bowl. Bitcoin was to be accepted for ticket and concession sales at the game as part of the sponsorship, and the sponsorship itself was also paid for using bitcoin.
In July 2014 Newegg and Dell started accepting bitcoin.
In September 2014 TeraExchange, LLC, received approval from the U.S.Commodity Futures Trading Commission "CFTC" to begin listing an over-the-counter swap product based on the price of a bitcoin. The CFTC swap product approval marks the first time a U.S. regulatory agency approved a bitcoin financial product.
In December 2014 Microsoft began to accept bitcoin to buy Xbox games and Windows software.
In January 2015 Coinbase raised 75 million USD as part of a Series C funding round, smashing the previous record for a bitcoin company. Less than one year after the collapse of Mt. Gox, United Kingdom-based exchange Bitstamp announced that their exchange would be taken offline while they investigate a hack which resulted in about 19,000 bitcoins (equivalent to roughly US$5 million at that time) being stolen from their hot wallet. The exchange remained offline for several days amid speculation that customers had lost their funds. Bitstamp resumed trading on 9 January after increasing security measures and assuring customers that their account balances would not be impacted.
In March 2015 21 Inc announced it had raised 116 million USD in venture funding, the largest amount for any digital currency-related companies.
As of August 2015 it was estimated that 160,000 merchants accept bitcoin payments.Barclays announced that they would become the first UK high street bank to start accepting bitcoin, with a plan to facilitate users to make charitable donations using the cryptocurrency outside their systems. They partnered in April 2016 with mobile payment startup Circle Internet Financial.
In October 2015, a proposal was submitted to the Unicode Consortium to add a codepoint for the bitcoin symbol.
In January 2016, the network rate exceeded 1 exahash/sec.
In March 2016, the Cabinet of Japan recognized virtual currencies like bitcoin as having a function similar to real money.Bidorbuy, the largest South African online marketplace, launched bitcoin payments for both buyers and sellers.
In April 2016, Steam started accepting bitcoin as payment for video games and other online media.
In July 2016, researchers published a paper showing that by November 2013 bitcoin commerce was no longer driven by "sin" activities but instead by legitimate enterprises. Uber switched to bitcoin in Argentina after the government blocked credit card companies from dealing with Uber.
In August 2016, a major bitcoin exchange, Bitfinex, was hacked and nearly 120,000 BTC (around $60m) was stolen.
In September 2016, the number of bitcoin ATMs had doubled over the last 18 months and reached 771 ATMs worldwide.
In November 2016, the Swiss Railway operator SBB (CFF) upgraded all their automated ticket machines so that bitcoin could be bought from them using the scanner on the ticket machine to scan the bitcoin address on a phone app.
Bitcoin generates more academic interest year after year; the number of Google Scholar articles published mentioning bitcoin grew from 83 in 2009, to 424 in 2012, and 3580 in 2016. Also, the academic Ledger (journal) published its first issue. It is edited by Peter Rizun.
The number of businesses accepting bitcoin continues to increase. In January 2017, NHK reported the number of online stores accepting bitcoin in Japan had increased 4.6 times over the past year. BitPay CEO Stephen Pair declared the company's transaction rate grew 3× from January 2016 to February 2017, and explained usage of bitcoin is growing in B2B supply chain payments.
Bitcoin gains more legitimacy among lawmakers and legacy financial companies. For example, Japan passed a law to accept bitcoin as a legal payment method, and Russia has announced that it will legalize the use of cryptocurrencies such as bitcoin. And Norway’s largest online bank, Skandiabanken, integrate bitcoin accounts.
In the first half of 2017, 1 bitcoin surpassed the spot price of an ounce of gold for the first time, and subsequently broke its all-time high, reaching US$1,402.03 on 1 May 2017, and over US$1,800 on 11 May 2017. On 20 May 2017, the price of one bitcoin passed US$2,000 for the first time.
In March 2017, the number of GitHub projects related to bitcoin passed 10,000.
Exchange trading volumes continue to increase. For the 6-month period ending March 2017, Mexican exchange Bitso saw trading volume increase 1500%. Between January and May 2017 Poloniex saw an increase of more than 600% active traders online and regularly processed 640% more transactions.
In June 2017, the bitcoin symbol was encoded in Unicode version 10.0 at position U+20BF (₿) in the Currency Symbols block.
On 1 August 2017 bitcoin split into two derivative digital currencies, the classic bitcoin (BTC) and the Bitcoin Cash (BCH).
On 5 August 2017, the price of one BTC passed US$3,000 for the first time.
On 12 August 2017, the price of one BTC passed US$4,000 for the first time.
Two days later, the price of one BTC hit a record high of US$4,400 for the first time.
The price of a bitcoin reached US$1,139.9 on 4 January 2017. (semi logarithmic plot)
Among the factors which may have contributed to this rise were the European sovereign-debt crisis—particularly the 2012–2013 Cypriot financial crisis—statements by FinCEN improving the currency's legal standing and rising media and Internet interest.
Until 2013, almost all market with bitcoins were in US $.
As the market valuation of the total stock of bitcoins approached US$1 billion, some commentators called bitcoin prices a bubble. In early April 2013, the price per bitcoin dropped from $266 to around $50 and then rose to around $100. Over two weeks starting late June 2013 the price dropped steadily to $70. The price began to recover, peaking once again on 1 October at $140. On 2 October, The Silk Road was seized by the FBI. This seizure caused a flash crash to $110. The price quickly rebounded, returning to $200 several weeks later. The latest run went from $200 on 3 November to $900 on 18 November. Bitcoin passed US$1,000 on 28 November 2013 at Mt. Gox.
Prices fell to around $400 in April 2014, before rallying in the middle of the year. They then declined to not much more than $200 in early 2015.
In the second quarter of 2017, prices more than tripled from $1200 to over $4000.
Main article: Satoshi Nakamoto
"Satoshi Nakamoto" is presumed to be a pseudonym for the person or people who designed the original bitcoin protocol in 2008 and launched the network in 2009. Nakamoto was responsible for creating the majority of the official bitcoin software and was active in making modifications and posting technical information on the BitcoinTalk Forum. Investigations into the real identity of Satoshi Nakamoto were attempted by The New Yorker and Fast Company. The New Yorker's investigation brought up at least two possible candidates: Michael Clear and Vili Lehdonvirta. Fast Company's investigation brought up circumstantial evidence linking an encryption patent application filed by Neal King, Vladimir Oksman and Charles Bry on 15 August 2008, and the bitcoin.org domain name which was registered 72 hours later. The patent application (#20100042841) contained networking and encryption technologies similar to bitcoin's, and textual analysis revealed that the phrase "... computationally impractical to reverse" appeared in both the patent application and bitcoin's whitepaper. All three inventors explicitly denied being Satoshi Nakamoto. In May 2013, Ted Nelson speculated that Japanese mathematician Shinichi Mochizuki is Satoshi Nakamoto. Later in 2013 the Israeli researchers Dorit Ron and Adi Shamir pointed to Silk Road-linked Ross William Ulbricht as the possible person behind the cover. The two researchers based their suspicion on an analysis of the network of bitcoin transactions. These allegations were contested. Ron and Shamir later retracted their claim.
Nakamoto's involvement with bitcoin does not appear to extend past mid-2010. In April 2011, Nakamoto communicated with a bitcoin contributor, saying that he had "moved on to other things".
Stefan Thomas, a Swiss coder and active community member, graphed the time stamps for each of Nakamoto's 500-plus bitcoin forum posts; the resulting chart showed a steep decline to almost no posts between the hours of 5 a.m. and 11 a.m. Greenwich Mean Time. Because this pattern held true even on Saturdays and Sundays, it suggested that Nakamoto was asleep at this time, and the hours of 5 a.m. to 11 a.m. GMT are midnight to 6 a.m. Eastern Standard Time (North American Eastern Standard Time). Other clues suggested that Nakamoto was British: A newspaper headline he had encoded in the genesis block came from the UK-published newspaper The Times, and both his forum posts and his comments in the bitcoin source code used British English spellings, such as "optimise" and "colour".
An Internet search by an anonymous blogger of texts similar in writing to the bitcoin whitepaper suggests Nick Szabo's "bit gold" articles as having a similar author. Nick denied being Satoshi, and stated his official opinion on Satoshi and bitcoin in a May 2011 article.
In a March 2014 article in Newsweek, journalist Leah McGrath Goodman doxed Dorian S. Nakamoto of Temple City, California, saying that Satoshi Nakamoto is the man's birth name. Her methods and conclusion drew widespread criticism.
In June 2016, the London Review of Books published a piece by Andrew O'Hagan about Nakamoto.
On 12 March 2013, a bitcoin miner running version 0.8.0 of the bitcoin software created a large block that was considered invalid in version 0.7 (due to an undiscovered inconsistency between the two versions). This created a split or "fork" in the blockchain since computers with the recent version of the software accepted the invalid block and continued to build on the diverging chain, whereas older versions of the software rejected it and continued extending the blockchain without the offending block. This split resulted in two separate transaction logs being formed without clear consensus, which allowed for the same funds to be spent differently on each chain. In response, the Mt. Gox exchange temporarily halted bitcoin deposits. The exchange rate fell 23% to $37 on the Mt. Gox exchange but rose most of the way back to its prior level of $48.
Miners resolved the split by downgrading to version 0.7, putting them back on track with the canonical blockchain. User funds largely remained unaffected and were available when network consensus was restored. The network reached consensus and continued to operate as normal a few hours after the split.
On 18 March 2013, the Financial Crimes Enforcement Network (or FinCEN), a bureau of the United States Department of the Treasury, issued a report regarding centralized and decentralized "virtual currencies" and their legal status within "money services business" (MSB) and Bank Secrecy Act regulations. It classified digital currencies and other digital payment systems such as bitcoin as "virtual currencies" because they are not legal tender under any sovereign jurisdiction. FinCEN cleared American users of bitcoin of legal obligations by saying, "A user of virtual currency is not an MSB under FinCEN's regulations and therefore is not subject to MSB registration, reporting, and recordkeeping regulations." However, it held that American entities who generate "virtual currency" such as bitcoins are money transmitters or MSBs if they sell their generated currency for national currency: "...a person that creates units of convertible virtual currency and sells those units to another person for real currency or its equivalent is engaged in transmission to another location and is a money transmitter." This specifically extends to "miners" of the bitcoin currency who may have to register as MSBs and abide by the legal requirements of being a money transmitter if they sell their generated bitcoins for national currency and are within the United States. Since FinCEN issued this guidance, dozens of virtual currency exchangers and administrators have registered with FinCEN, and FinCEN is receiving an increasing number of suspicious activity reports (SARs) from these entities.
Additionally, FinCEN claimed regulation over American entities that manage bitcoins in a payment processor setting or as an exchanger: "In addition, a person is an exchanger and a money transmitter if the person accepts such de-centralized convertible virtual currency from one person and transmits it to another person as part of the acceptance and transfer of currency, funds, or other value that substitutes for currency."
In summary, FinCEN's decision would require bitcoin exchanges where bitcoins are traded for traditional currencies to disclose large transactions and suspicious activity, comply with money laundering regulations, and collect information about their customers as traditional financial institutions are required to do.
Patrick Murck of the Bitcoin Foundation criticized FinCEN's report as an "overreach" and claimed that FinCEN "cannot rely on this guidance in any enforcement action".[non-primary source needed]
Jennifer Shasky Calvery, the director of FinCEN said, "Virtual currencies are subject to the same rules as other currencies. ... Basic money-services business rules apply here."
In its October 2012 study, Virtual currency schemes, the European Central Bank concluded that the growth of virtual currencies will continue, and, given the currencies' inherent price instability, lack of close regulation, and risk of illegal uses by anonymous users, the Bank warned that periodic examination of developments would be necessary to reassess risks.
In 2013, the U.S. Treasury extended its anti-money laundering regulations to processors of bitcoin transactions.
In June 2013, Bitcoin Foundation board member Jon Matonis wrote in Forbes that he received a warning letter from the California Department of Financial Institutions accusing the foundation of unlicensed money transmission. Matonis denied that the foundation is engaged in money transmission and said he viewed the case as "an opportunity to educate state regulators."
In late July 2013, the industry group Committee for the Establishment of the Digital Asset Transfer Authority began to form to set best practices and standards, to work with regulators and policymakers to adapt existing currency requirements to digital currency technology and business models and develop risk management standards.
In 2014, the U.S. Securities and Exchange Commission filed an administrative action against Erik T. Voorhees, for violating Securities Act Section 5 for publicly offering unregistered interests in two bitcoin websites in exchange for bitcoins.
Bitcoins can be stored in a bitcoin cryptocurrency wallet. Theft of bitcoin has been documented on numerous occasions. At other times, bitcoin exchanges have shut down, taking their clients' bitcoins with them. A Wired study published April 2013 showed that 45 percent of bitcoin exchanges end up closing.
On 19 June 2011, a security breach of the Mt. Gox bitcoin exchange caused the nominal price of a bitcoin to fraudulently drop to one cent on the Mt. Gox exchange, after a hacker used credentials from a Mt. Gox auditor's compromised computer illegally to transfer a large number of bitcoins to himself. They used the exchange's software to sell them all nominally, creating a massive "ask" order at any price. Within minutes, the price reverted to its correct user-traded value. Accounts with the equivalent of more than US$8,750,000 were affected.
In July 2011, the operator of Bitomat, the third-largest bitcoin exchange, announced that he had lost access to his wallet.dat file with about 17,000 bitcoins (roughly equivalent to US$220,000 at that time). He announced that he would sell the service for the missing amount, aiming to use funds from the sale to refund his customers.
In August 2011, MyBitcoin, a now defunct bitcoin transaction processor, declared that it was hacked, which caused it to be shut down, paying 49% on customer deposits, leaving more than 78,000 bitcoins (equivalent to roughly US$800,000 at that time) unaccounted for.
In early August 2012, a lawsuit was filed in San Francisco court against Bitcoinica — a bitcoin trading venue — claiming about US$460,000 from the company. Bitcoinica was hacked twice in 2012, which led to allegations that the venue neglected the safety of customers' money and cheated them out of withdrawal requests.
In late August 2012, an operation titled Bitcoin Savings and Trust was shut down by the owner, leaving around US$5.6 million in bitcoin-based debts; this led to allegations that the operation was a Ponzi scheme. In September 2012, the U.S. Securities and Exchange Commission had reportedly started an investigation on the case.
In September 2012, Bitfloor, a bitcoin exchange, also reported being hacked, with 24,000 bitcoins (worth about US$250,000) stolen. As a result, Bitfloor suspended operations. The same month, Bitfloor resumed operations; its founder said that he reported the theft to FBI, and that he plans to repay the victims, though the time frame for repayment is unclear.
On 3 April 2013, Instawallet, a web-based wallet provider, was hacked, resulting in the theft of over 35,000 bitcoins which were valued at US$129.90 per bitcoin at the time, or nearly $4.6 million in total. As a result, Instawallet suspended operations.
On 11 August 2013, the Bitcoin Foundation announced that a bug in a pseudorandom number generator within the Android operating system had been exploited to steal from wallets generated by Android apps; fixes were provided 13 August 2013.
In October 2013, Inputs.io, an Australian-based bitcoin wallet provider was hacked with a loss of 4100 bitcoins, worth over A$1 million at time of theft. The service was run by the operator TradeFortress. Coinchat, the associated bitcoin chat room, has been taken over by a new admin.
On 26 October 2013, a Hong-Kong based bitcoin trading platform owned by Global Bond Limited (GBL) vanished with 30 million yuan (US$5 million) from 500 investors.
Mt. Gox, the Japan-based exchange that in 2013 handled 70% of all worldwide bitcoin traffic, declared bankruptcy in February 2014, with bitcoins worth about $390 million missing, for unclear reasons. The CEO was eventually arrested and charged with embezzlement.
On 3 March 2014, Flexcoin announced it was closing its doors because of a hack attack that took place the day before. In a statement that now occupies their homepage, they announced on 3 March 2014 that "As Flexcoin does not have the resources, assets, or otherwise to come back from this loss [the hack], we are closing our doors immediately." Users can no longer log into the site.
Chinese cryptocurrency exchange Bter lost $2.1 million in BTC in February 2015.
The Slovenian exchange Bitstamp lost bitcoin worth $5.1 million to a hack in January 2015.
The US-based exchange Cryptsy declared bankruptcy in January 2016, ostensibly because of a 2014 hacking incident; the court-appointed receiver later alleged that Cryptsy's CEO had stolen $3.3 million.
In May 2016, Gatecoin closed temporarily after a breach had caused a loss of about $2 million in cryptocurrency. It subsequently relaunched its exchange in August 2016 and is slowly reimbursing its customers.
In August 2016, hackers stole some $72 million in customer bitcoin from the Hong-Kong-based exchange Bitfinex.
See also: Legality of bitcoin by country or territory
In 2012, the Cryptocurrency Legal Advocacy Group (CLAG) stressed the importance for taxpayers to determine whether taxes are due on a bitcoin-related transaction based on whether one has experienced a "realization event": when a taxpayer has provided a service in exchange for bitcoins, a realization event has probably occurred and any gain or loss would likely be calculated using fair market values for the service provided."
In August 2013, the German Finance Ministry characterized bitcoin as a unit of account, usable in multilateral clearing circles and subject to capital gains tax if held less than one year.
On 5 December 2013, the People's Bank of China announced in a press release regarding bitcoin regulation that whilst individuals in China are permitted to freely trade and exchange bitcoins as a commodity, it is prohibited for Chinese financial banks to operate using bitcoins or for bitcoins to be used as legal tender currency, and that entities dealing with bitcoins must track and report suspicious activity to prevent money laundering. The value of bitcoin dropped on various exchanges between 11 and 20 percent following the regulation announcement, before rebounding upward again.
On 18 June 2014, it was announced that bitcoin payment service provider BitPay would become the new sponsor of the St. Petersburg Bowl game under a two-year deal, renamed the Bitcoin St. Petersburg Bowl. Bitcoin will be accepted for ticket and concession sales as part of the sponsorship, and the sponsorship itself was also paid for using bitcoin. On 2 April 2015, after one year of sponsorship, BitPay declined to renew sponsorship of the game.
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