Foundations of Blockchain

Immutability

Blockchain is a ledger that doesn't allow you to update or delete existing records. The data recorded on the blockchain is supposed to remain for eternity. This makes a blockchain an immutable data structure. Unlike with traditional record-keeping technologies, a record cannot be erased once it is included in the blockchain. The only way to update a record is by creating a new record that will undo the effect of the previous record. Update operations are expensive in blockchain because each record insertion consumes time and fees.

Immutability is one of the key characteristics of blockchain, so it's essential that the selected use case can make use of the immutable nature of blockchain.