Bitcoin

Bitcoin is a decentralized digital currency and payment network that was described in a white paper published in October 2008 under the pseudonym Satoshi Nakamoto, whose real identity has never been established. The network went live in January 2009 when Nakamoto mined the first block of the chain, called the genesis block, and released the software as open source. Rather than relying on a bank or other central authority, Bitcoin keeps a public ledger of every transaction, the blockchain, copied on many independent computers that act as nodes in a peer-to-peer network. Cryptography prevents anyone from spending coins they do not control, and agreement between the nodes about the ledger is reached through proof of work, a competitive puzzle-solving process called mining that is carried out on specialised computers and uses a great deal of electricity. Its design combined earlier ideas such as Hashcash, b-money and bit gold into the first working system of this kind, and it became the model for the many cryptocurrencies that followed.