Blockchain
A distributed digital ledger that records transactions across a network of computers in a way that makes the data immutable, transparent, and resistant to modification.
A blockchain is a decentralized, distributed digital ledger that records transactions across many computers so that any involved record cannot be altered retroactively without the alteration of all subsequent blocks and the consensus of the network. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data, forming an immutable chain. Blockchains are secured through consensus mechanisms — primarily Proof of Work (used by Bitcoin) and Proof of Stake (used by Ethereum and most modern chains). The technology eliminates the need for trusted intermediaries by allowing participants who don't know or trust each other to maintain a shared, tamper-proof record of transactions. Beyond cryptocurrencies, blockchain technology is used for supply chain tracking, digital identity, voting systems, healthcare records, and — increasingly in 2026 — real-world asset tokenization. The key innovation is that blockchain creates digital scarcity and verifiable ownership without a central authority.