All terms
Agent Security

Cryptographic Receipts

Signed, verifiable proof tokens produced for every authorization decision. Non-repudiable audit trail that can be verified without trusting the authorization service.


Cryptographic receipts are signed, portable proof tokens produced for every authorization decision. Each receipt contains the decision (allowed/denied), the context (who, what, when, scope), and a cryptographic signature — making the audit trail non-repudiable and independently verifiable.

Why signatures matter

Without cryptographic receipts, the audit trail is a database you trust. With receipts, the audit trail is a set of signed proofs you can verify without trusting the authorization service — even offline. An auditor can validate that a specific decision was made at a specific time without access to the live system.

Design decisions

  • Ed25519 signatures: fast, small, modern — sub-millisecond signing time
  • Merkle tree chaining: each receipt links to the previous one, preventing insertion/deletion
  • Key rotation: signing keys rotate on a schedule; verification keys are published