Blockchains have been described as a value-exchange protocol. It is a decentralized and distributed digital ledger that is used to record
transactions across many computers so that the record cannot be altered retroactively. A blockchain database is managed autonomously using a peer-to-peer network and a distributed timestamping server. Blocks hold batches of valid transactions that are hashed and encoded into a Merkle tree. Each block includes the cryptographic hash of the prior block in the blockchain, linking the two. The linked blocks form a chain. This iterative process confirms the integrity of the previous block, all the way back to the original genesis block. In addition to a secure hash-based history, any blockchain has a specified algorithm for scoring different versions of the history so that one with a higher value can be selected over others.