A core feature of blockchains that makes their ledgers, the data record of transactions, unchangeable and unalterable. Immutability drives the trustworthiness and integrity of blockchain data as chain transactions and rulesets are protected from fraud, hacking and other wrongdoing
Example
“For example, once a Bitcoin transaction is confirmed and added to the blockchain, it cannot be reversed or altered, which is why users must double-check wallet addresses before sending funds.”