What fundamental characteristic of Distributed Ledger Technology (DLT), such as blockchain, ensures that once a data entry or transaction is verified and recorded, it cannot be retroactively altered or deleted?

💡 Explanation:

Immutability is the core security feature of DLTs like blockchain. Once a block of data is added to the chain, it is linked cryptographically to the previous blocks, making tampering virtually impossible without altering every subsequent block in the ledger.