Quantum-Safe Audit Log Relying on Attestation Procedures

Last year, we examined how hardware security modules can provide cryptographic attestation, i.e., a signed snapshot of the state of an HSM and/or of its keys. Trust in cryptographic infrastructure, however, often requires more than a snapshot; it requires proof of history. This presentation introduces cryptographically verifiable audit logs for hardware security modules, a mechanism that produces a tamper-evident, independently verifiable record of every operation performed on a cryptographic object over its lifetime. Where attestation tells you what a key looks like today, an audit log tells you everything that was done to it and when. Key ceremonies require a verifiable sequence of authorized operations that no snapshot can reconstruct; key migration requires a temporary export, so the destination device's attestation cannot prove the process was correct, but the combined audit logs of both devices can. The cryptographic architecture behind this relies on event chaining and attested log state, with tooling that runs entirely outside the HSM so that an auditor can verify the record without device access. For long-term validity, all of this must rest on quantum-safe roots of trust provisioned at manufacturing time.