The blockchain, a distributed digital ledger, is what Bitcoin is based on. As the name suggests, blockchain is a linked database made up of blocks that store information about each transaction, such as the date and time, total amount, buyer and seller, and a unique identifier for each exchange. Entries are linked in chronological order to form a digital blockchain. Entries are linked in chronological order to form a digital blockchain. Blockchain is decentralized, which means any central authority does not control it.