Based on a free market ideology, bitcoin was invented in 2008 by Satoshi Nakamoto, an unknown person.[8] Use of bitcoin as a currency began in 2009,[9] with the release of its open-source implementation.[10]: ch. 1 In 2021, El Salvador adopted it as legal tender.[4]Bitcoin is currently used more as a store of value and less as a medium of exchange or unit of account. It is mostly seen as an investmentand has been described by many scholars as an economic bubble.[11] As bitcoin is pseudonymous, its use by criminals has attracted the attention of regulators, leading to its ban by several countries as of 2021.[12]