The Difference Between Protecting a Secret at Rest and Protecting It at Inference Time

Most secrets management tools were designed around one threat: unauthorized access to stored credentials. Vault, Secrets Manager, Doppler, 1Password — these tools encrypt credentials at rest, control who can retrieve them, and audit access. For the threat they were built for, they work well. AI agents introduced a different threat. The tools built for the first one do not address the second. Protection at rest A credential at rest is a credential in storage, whether in a database, a file, or a vault. The threat is unauthorized access to that storage. The defense is encryption, access control, and audit logging. When you store a Stripe API key in HashiCorp Vault, the key is encrypted at rest. Only authorized principals can retrieve it. Every retrieval is logged. The threat model assumes someone gains access to the storage system, and the defense is making that access difficult and detectable. This is a well-understood problem with mature solutions that have existed for years. Protection