(also blockchain)
A decentralized system for recording and storing information. Blockchains are a kind of distributed ledger technology (DLT) made up of records (called “blocks”) linked in a sequence — each block has the unique number of the preceding block, forming a chain.
Unlike traditional databases, which are typically held on one server, blockchains are decentralized over P2P networks. Every node in the network has a full copy of the blockchain, and each new block must be checked and validated by a majority of node operators. Because no single block can be changed without also modifying every other block down the line, this makes blockchain transactions practically irreversible.