Why Tamper-Evident Audit Trails Matter for AI Compliance
Mutable logs are stories. Chained, anchored records are evidence. Here is what tamper-evidence actually means for AI systems.
Regulators, auditors, and enterprise buyers have converged on the same question about AI systems: can you prove what your model decided, and can you prove no one changed the record? Tamper-evident audit trails answer both.
Tamper-resistant vs tamper-evident
- Tamper-resistant means it is hard to change a record. Access controls, WORM buckets, RBAC.
- Tamper-evident means if a record is changed, anyone can detect it — cryptographically, without trusting the system that stored it.
Regulators care about the second one. A broken hash chain is a mathematical fact; "only DBAs can write to it" is a policy claim.
What "tamper-evident" actually requires
1. Append-only storage. Records cannot be updated or deleted in place. 2. Cryptographic chaining. Each record includes the hash of the previous record. 3. External anchoring. The head of the chain is periodically committed to something outside your system.
Miss any of these and the guarantee collapses.
Why enterprise buyers care
Procurement questionnaires now routinely ask: *describe your AI decision logging and how you prevent tampering.* A hash-chained, externally anchored log is the shortest correct answer.