Blockchain

A blockchain is a decentralized, distributed, and oftentimes public, digital ledger that is used to record transactions across many computers so that any involved record cannot be altered retroactively, without the alteration of all subsequent blocks.

A blockchain is a distributed database that maintains a continuously growing list of transactional data records hardened against tampering and revision, even by operators of the data store's nodes. The initial and most widely known application of the blockchain technology is the public ledger of transactions for bitcoin and the inspiration of similar distributed ledgers known as altchains. Each blockchain record is enforced cryptographically and hosted on machines working as data store nodes.