A ledger is a list of results. Each line in an asset ledger records a transaction and the resulting balance.
Transactions must be
To maintain the integrity of the data in a centralised asset ledger, a central authority is trusted to create transactions and to secure access to the ledger.
Data integrity can be accomplished with cryptographic techniques instead of a central authority. Peer-to-peer consensus protocols enable atomicity, durability and consistency of transactions in a distributed system.
A blockchain is one type of distributed ledger data structure.