Bitcoin is a digital currency created in 2009 by Satoshi Nakamoto. The name refers both to the open source software he designed to make use of the currency and to the peer-to-peer network formed by running that software.

Unlike some other digital currencies, Bitcoin avoids central authorities and issuers. Bitcoin uses a distributed database spread across nodes of a peer-to-peer network to journal transactions, and uses digital signatures and proof-of-work to provide basic security functions, such as ensuring that bitcoins can be spent only once per owner and only by the person who owns them.

Bitcoins, often abbreviated as BTC, can be saved on a personal computer in the form of a wallet file or kept with a third party wallet service, and in either case bitcoins can be sent over the Internet to anyone with a Bitcoin address. The peer-to-peer topology and lack of central administration are features that make it infeasible for any authority (governmental or otherwise) to manipulate the quantity of bitcoins in circulation, thereby mitigating inflation.