Immutable storage is a data persistence model in which written records cannot be modified or deleted for a defined period, preserving their integrity against tampering and accidental loss. It is realised through write-once-read-many policies, append-only logs, content addressing, and cryptographic hashing, and underpins audit trails, regulatory retention, and ransomware resilience. Immutability provides verifiable evidence that data has not changed since it was committed.
Overview
- Immutable storage trades the ability to overwrite for strong guarantees that committed data is durable and verifiable.
- Retention locks and legal-hold mechanisms prevent deletion even by privileged administrators for a configured period.
- Content addressing ties each object to the hash of its contents, so any alteration produces a different address.
Mechanisms
- Write-once-read-many policies block modification after the initial write.
- Append-only logs record new state as additional entries rather than overwriting history.
- Cryptographic hashing and content addressing make tampering detectable.
- Retention periods and legal holds enforce minimum durability windows.
Applications
- Compliance audit trails and regulatory record retention.
- Ransomware-resistant backups that cannot be encrypted or deleted by attackers.
- Verifiable provenance for documents, logs, and decentralised content on systems like IPFS and blockchains.