The Relay Pattern: Encryption, Signing And Ordering Are Three Mechanisms

Summary

Untangles three mechanisms that get bundled as one: encryption says who may read, signing says who acted, and ordering comes from data dependencies rather than from either. The brief that raised per-agent keys and the names-are-identities problem a registry would answer — and that stated, as the limit of its own control, that per-agent keys constrain which agent acts at which step and not what that agent does within its step. That stated limit is one of the three the execution broker closes.

Key concepts

• Three mechanisms, not one — the same discipline applied to authorisation rather than messaging
• The stated limit — which agent acts when, not what it does within its step
• Who may claim to be a participant — left open here, answered by registered anchors
• Replay protection — needs a nonce inside the signed payload, and is easily left out

Key ideas

• A compromised agent can read its input, do something wrong, sign it correctly and pass it on, with every cryptographic check passing.
• Ordering is not a cryptographic property and should not be sought from encryption or signatures.
• Per-agent keys are the attribution mechanism; the registry is where the verifying keys would live.
• If anybody can register a name and publish a key for it, a message chain can be redirected.

On this site

Foundation. Supplies the three-mechanisms discipline the mandate and execution pages both rely on.

Read the document