Bitcoin is the world's first decentralized cryptocurrency, created in 2009 by the pseudonymous Satoshi Nakamoto. It enables peer-to-peer electronic cash transactions without intermediaries like banks or governments, operating on a blockchain secured by Proof of Work mining and the SHA-256 cryptographic algorithm. With a fixed supply cap of 21 million coins and programmatic halvings every four years that reduce miner rewards, Bitcoin is designed as a deflationary digital asset often called "digital gold." Its value stems from solving the double-spending problem without trusted intermediaries, creating the first truly scarce digital asset with censorship resistance and permissionless access that no government, corporation, or individual can control. Bitcoin operates as a decentralized peer-to-peer network where transactions are recorded on a public ledger called the blockchain, distributed across thousands of computers globally.