Bitcoin is an electronic money created in 2009 by Satoshi Nakamoto. The name is also associated with open source software that he designed, and also uses peer-to-peer networks without centralized storage or a single administrator where the United States Treasury calls bitcoin a decentralized currency. Unlike most currencies, bitcoin does not depend on trusting the main publisher. Bitcoin uses a database that is distributed and spreads to nodes from a P2P network to transaction journals, and uses cryptography to provide basic security functions, such as ensuring that bitcoin-bitcoin can only be spent by people owning it, and should never be done more from one time.