Bitcoin cryptocurrency

Bitcoin is the first successful decentralized digital currency, launched in 2009 by the pseudonymous Satoshi Nakamoto, and it introduced a public blockchain that records every transfer in a distributed ledger that anyone can read and that is cryptographically secured and effectively immutable. The protocol solved the double-spend problem for digital money by combining peer-to-peer propagation with a Proof-of-Work consensus where miners expend computing power to validate and add blocks. Block producers receive newly minted coins as payment, and the issuance schedule is strictly capped so that no more than 21 million coins will ever exist, with block rewards halving about every four years until issuance tapers off in the distant future. Bitcoin’s design deliberately removes trusted intermediaries and gives individuals full custody of their funds when they control their private keys, while exchanges and custodial services sometimes retain keys on behalf of users and thus reintroduce counterparty risk. The network’s security rests on decentralization and economic cost; rewriting history would require commanding a majority of global hashing power, which makes malicious takeover practically infeasible. Transactions are pseudonymous because addresses are not direct personal identifiers, yet every movement is public on-chain and can be analyzed, so privacy requires operational discipline and tool choices. Two notable protocol upgrades demonstrate how the network evolves: Segregated Witness reduced transaction data size by separating signature data and thus increased throughput per block, and Taproot improved privacy and efficiency for multi-signature and conditional spending by making complex scripts appear like simple payments on-chain. Bitcoin does not natively support general-purpose smart contracts in the way some other chains do, but experimental inscription systems have appeared that attach metadata to satoshis and create NFT-like artifacts with different permanence and trade-offs. Developers propose changes through Bitcoin Improvement Proposals, and adoption requires broad consensus among node operators, miners, wallet developers and users. For secure access, private keys should be stored in devices or software that keep signing keys offline whenever possible, and transactions should be verified on the signing device to avoid remote tampering. The system’s value lies in a compact set of trade-offs: predictable issuance, strong immutability, open validation, censorship resistance and a permissionless settlement layer for cross-border value transfer. This makes Bitcoin a monetary infrastructure that allows anyone to be their own bank while demanding responsibility for custody, key management and an understanding of the network’s operational limits.