Cryptographic audit chain
Every value can be verified, independently
Every value is signed with ECDSA when it is read, batched per device per cycle. The signatures are chained with SHA-256: each block points at the one before it, so a value altered afterwards breaks the chain and the break is locatable. Not a policy, a proof.
E-signatures
Who did what, and exactly when
User actions inside MOFF are signed with identity, timestamp and source IP, and failed attempts are logged the same way. Combined with the signed process data, a setpoint change becomes provable rather than remembered. Designed against 21 CFR Part 11 and ALCOA+.