Bitcoin is a permissionless, decentralized monetary network and settlement asset that enables final value transfer without a central operator, with BTC used to pay transaction fees and to anchor economic incentives for network security. Introduced by Satoshi Nakamoto in the 2008 white paper and launched with the genesis block on 3 January 2009, Bitcoin enforces transaction ordering via Proof-of-Work mining (SHA-256) and a globally replicated public ledger. Its monetary policy is protocol-defined and supply-constrained: the block subsidy halves every 210,000 blocks toward a hard cap of 21 million BTC, while mining difficulty retargets every 2,016 blocks to keep average block intervals near 10 minutes. This combination of transparent issuance rules and censorship-resistant settlement has made Bitcoin a reference asset for spot markets and a common underlying for custody and derivatives infrastructure in jurisdictions where such exposure is permitted.