Digital ledger

One of the core capabilities of the blockchain is the digital ledger, a type of database or system of records, which is distributed (shared, replicated, and synchronized) by the network layer among the participants in the network. The digital ledger records the transactions, such as the transfer of assets or data, from one participant to another, or among multiple participants in the network. Commonly, a key/value data structure is used to record these transactions and its assets. More advanced digital ledgers, such as the one used by Ethereum, NEO, and Hyperledger, also record smart contract code in the ledger as its own asset. Some digital ledgers have the ability to save the current state separately from the transactions log, which allows third-party applications to query the data easily without needing to replay the entire transaction log.