Glossary
Non-Repudiation
Non-repudiation means a record of an action is bound tightly enough to the identity that performed it — typically through cryptographic signing — that the actor cannot plausibly claim it was someone else, or that the record was fabricated after the fact. It is a stronger property than an ordinary log entry, which can usually be edited, deleted, or attributed incorrectly by anyone with write access to the log.
Systems that need non-repudiation typically sign each decision or action record with a key controlled by the party responsible for it, and store the signature alongside the record rather than trusting a database's own access controls to keep the history honest. The payoff is a record that a third party — an auditor, a court, a security team investigating an incident — can verify independently, without having to trust the system operator's word for what happened.