A blockchain is a type of distributed ledger, which is a digital record of transactions that is shared and maintained by a network of computers.
The main difference between a blockchain and a distributed ledger is that a blockchain is a specific type of distributed ledger that is secured using cryptography. A blockchain is an immutable, sequential chain of records, known as blocks, that are managed by a cluster of computers that are not owned by any single entity. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data. By design, blockchains are resistant to data modification, making them secure and reliable.
For example, Bitcoin is a blockchain-based cryptocurrency. It is a digital asset designed to work as a medium of exchange and is secured using cryptography. Bitcoin transactions are stored in blocks and recorded on a public distributed ledger called the blockchain. The blockchain is a shared public ledger that records all Bitcoin transactions and is maintained by a network of computers.