Bitcoin, created in 2008 by the unknown Satoshi Nakamoto, is the first decentralized cryptocurrency, launched in 2009. Functioning on a free-market ideology, it operates as an open-source system. In 2021, El Salvador adopted it as legal tender. Predominantly used for investment, some consider it an economic bubble. Its pseudonymous nature has drawn regulatory scrutiny due to illicit activities, resulting in bans in certain countries as of 2021.
In 1992, cryptographers Cynthia Dwork and Moni Naor first proposed the idea that solutions to computational puzzles could have some value.
In 1997, Adam Back independently rediscovered the concept and developed Hashcash, a proof-of-work scheme for spam control.
In 1998, Wei Dai (b-money) and Nick Szabo (bit gold) made the first proposals for distributed digital scarcity-based cryptocurrencies.
In 2004, Hal Finney developed the first currency based on reusable proof of work.
In August 2008, the domain name bitcoin.org was registered.
On October 31, 2008, Satoshi Nakamoto posted a link to the bitcoin white paper, titled "Bitcoin: A Peer-to-Peer Electronic Cash System", to a cryptography mailing list.
In 2008, Bitcoin was invented by Satoshi Nakamoto, an unknown entity, based on a free-market ideology.
In January 2009, Nakamoto implemented the bitcoin software as open-source code and released it.
On January 3, 2009, the bitcoin network was created when Nakamoto mined the genesis block, embedding the text "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks".
Buying real-world goods with any virtual currency had been illegal in China since at least 2009.
In 2009, Nakamoto released the first bitcoin wallet program, simply named Bitcoin, as open-source software.
In 2009, the use of Bitcoin as a currency began with the release of its open-source implementation.
On May 22, 2010, the first known commercial transaction using bitcoin occurred when Laszlo Hanyecz bought two Papa John's pizzas for ₿10,000, now celebrated as "Bitcoin Pizza Day".
In 2010, Nakamoto disappeared after mining about one million bitcoins and handed control of the network alert key and code repository over to Gavin Andresen.
In February 2011, the dark web Silk Road exclusively accepted bitcoins as payment.
In September 2012, the Bitcoin Foundation was founded to promote bitcoin.
In 2012, Mt. Gox froze accounts containing bitcoins identified as stolen.
In March 2013, the US Financial Crimes Enforcement Network (FinCEN) established regulatory guidelines for "decentralized virtual currencies" such as bitcoin.
In May 2013, US authorities seized the unregistered exchange Mt. Gox.
In June 2013, the US Drug Enforcement Administration seized ₿11.02 from an individual attempting to use them to purchase illicit drugs.
In October 2013, the FBI seized about ₿30,000 from Silk Road, following the arrest of its founder Ross Ulbricht.
In 2013, a user lost ₿7,500, valued at US$7.5 million, by accidentally discarding a hard drive with the private key.
According to The Economist in 2014, bitcoin functions best as a medium of exchange.
In 2014, mining pool Ghash.io reached 51% mining power, causing safety concerns, but later voluntarily capped its power at 39.99% for the benefit of the whole network.
In 2015, The Economist noted that bitcoins had three qualities useful in a currency: they are "hard to earn, limited in supply and easy to verify".
In August 2017, the SegWit software upgrade was activated, intending to support the Lightning Network and improve scalability.
The percentage of bitcoin trading in the Chinese renminbi fell from over 90% in September 2017.
In December 2017, the Chicago Mercantile Exchange (CME) introduced the first futures on bitcoin.
As of December 2017, approximately ₿980,000 had been stolen from cryptocurrency exchanges.
In February 2018, the price of Bitcoin crashed after China imposed a complete ban on Bitcoin trading.
The percentage of bitcoin trading in the Chinese renminbi fell to less than 1% in June 2018.
A 2018 assessment by The Economist stated that cryptocurrencies met none of these three criteria: "hard to earn, limited in supply and easy to verify".
In November 2020, PayPal added support for bitcoin in the US.
In February 2021, bitcoin's market capitalization reached $1 trillion for the first time.
In September 2021, bitcoin became legal tender in El Salvador, alongside the US dollar.
In October 2021, the first bitcoin futures exchange-traded fund (ETF), called BITO, from ProShares was approved by the SEC and listed on the CME.
In November 2021, the Taproot soft-fork upgrade was activated, adding support for Schnorr signatures, improved smart contracts and Lightning Network functionality.
In 2021, El Salvador adopted Bitcoin as legal tender.
In June 2022, the bitcoin price fell following the collapses of TerraUSD, a stablecoin, and the Celsius Network, a cryptocurrency loan company.
As of 2022, a study estimated that bitcoin mining represented 0.4% of global electricity consumption.
As of June 2023, River Financial estimated that bitcoin had 81.7 million users, about 1% of the global population.
In January 2024, the first 11 US spot bitcoin ETFs began trading, offering direct exposure to bitcoin for the first time on American stock exchanges.
In December 2024, bitcoin price reached $100,000 for the first time, as US president-elect Donald Trump promised to make the US the "crypto capital of the planet" and to stockpile bitcoin.