Blockchain

A blockchain is a digital ledger that records transactions in blocks that are linked together in order. Each new block contains transaction data and a reference to the previous block, which creates a chain of records. In most crypto networks, this ledger is shared across many computers instead of being controlled by a single operator. A blockchain is used to track and confirm crypto ownership, validate transactions, and run smart contracts. Because each accepted block links to prior blocks, changing old records would require altering the chain’s history under the network’s rules.

When a user sends Bitcoin to a friend, the transaction is grouped into a block and added to the Bitcoin blockchain, creating a public record that can be viewed later.