$BTC Bitcoin is a decentralized cryptocurrency created in 2009 by a person (or group) using the pseudonym Satoshi Nakamoto. It operates without a central authority, relying on a peer-to-peer network and a technology called blockchain, which securely and transparently records all transactions. Its supply is limited to 21 million units, making it deflationary. It is often referred to as "digital gold" for its role as a store of value. Bitcoin is used both as an investment and as a means of payment, although its volatility and varying regulation limit its widespread adoption.