blockchain

A blockchain is a distributed digital ledger that securely records transactions across a network of computers. Each record, or “block,” contains a list of transactions and links to the previous block, forming a chronological “chain.” This structure makes the system resistant to tampering, as altering one block would require changing all subsequent blocks on the majority of network nodes. Blockchains are the foundation for many cryptocurrencies and are also used in various other applications requiring transparency, security, and decentralization.