Blockchain

A blockchain is a decentralized, distributed ledger that records transactions on multiple computers in a way that ensures the data cannot be altered retroactively without the alteration of all subsequent blocks. It enables secure, transparent, and tamper-resistant transactions without requiring a central authority or intermediary.
These distributed databases that maintain a continuously growing list of records, called blocks, are linked using cryptography. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data, making it inherently resistant to modification of the data.