Bitcoin

Bitcoin is the first and largest cryptocurrency, launched in 2009 by the pseudonymous developer Satoshi Nakamoto. It runs on an open peer-to-peer network where transactions are grouped into blocks and secured by proof-of-work mining, and its issuance is capped at 21 million coins, with the block reward cut in half at regular intervals in an event known as the halving. Bitcoin has no issuer, no support desk and no way to reverse a confirmed payment, so key management is entirely the holder's responsibility. Written with a capital B the word usually means the network and protocol; lowercase bitcoin, ticker BTC, means the unit itself. Its price is volatile and it is not a claim on any company or reserve.