A blockchain is a decentralized digital ledger of transactions that is used to record data in a secure and tamper-proof manner. A blockchain consists of a series of “blocks,” which contain a list of transactions. Each block is linked to the previous one, creating a chain of blocks that cannot be altered without changing the entire chain. This means that once a transaction is recorded on the blockchain, it cannot be deleted or altered. Furthermore, entries are distributed among many different users and computers, with each user maintaining a copy of the ledger. These aspects make the blockchain a powerful tool for recording and verifying data in a secure, trustworthy, and transparent way.