On 18 August 2008, the domain name "bitcoin.org" was registered.[27] In November that year, a link to a paper authored by Satoshi Nakamoto titled Bitcoin: A Peer-to-Peer Electronic Cash System[5] was posted to a cryptography mailing list.[27] Nakamoto implemented the bitcoin software as open source code and released it in January 2009 on SourceForge.[28][29][12] The identity of Nakamoto remains unknown.[11]
In January 2009, the bitcoin network came into existence after Satoshi Nakamoto mined the first ever block on the chain, known as the genesis block.[30][31] Embedded in the coinbase of this block was the following text:
The Times 03/Jan/2009 Chancellor on brink of second bailout for banks.[12]
This note has been interpreted as both a timestamp of the genesis date and a derisive comment on the instability caused by fractional-reserve banking.[32]:18
The receiver of the first bitcoin transaction was cypherpunk Hal Finney, who created the first reusable proof-of-work system (RPOW) in 2004.[33] Finney downloaded the bitcoin software the day it was released, and received 10 bitcoins from Nakamoto.[34][35] Other early cypherpunk supporters were Wei Dai, creator of bitcoin predecessor b-money, and Nick Szabo, creator of bitcoin predecessor bit gold.[36]
In the early days, Nakamoto is estimated to have mined 1 million bitcoins.[37] In 2010, Nakamoto handed the network alert key and control of the Bitcoin Core code repository over to Gavin Andresen, who later became lead developer at the Bitcoin Foundation.[38][39] Nakamoto subsequently disappeared from any involvement in bitcoin.[40] Andresen stated he then sought to decentralize control, saying: "As soon as Satoshi stepped back and threw the project onto my shoulders, one of the first things I did was try to decentralize that. So, if I get hit by a bus, it would be clear that the project would go on."[40] This left opportunity for controversy to develop over the future development path of bitcoin.[41]
On 1 August 2017, a hard fork of bitcoin was created, known as Bitcoin Cash. Bitcoin Cash has a larger block size limit and had an identical blockchain at the time of fork.[42][43] On 12 November another hard fork, Bitcoin Gold, was created. Bitcoin Gold changes the proof-of-work algorithm used in mining.[44][45]