Issuer
The one who asks. An accredited person with their credential in the app; a vehicle, robot or drone with the issuer SDK integrated into its onboard system; an onboard unit when the asset cannot integrate software. It presents verifiable identity, who operates it, what capabilities it declares and what action it requests.
Node
The one who decides. The door, the barrier, the dock, the crane, the lift, the charging point. It runs the five checks locally, it is the final authority, it works without a network and it cannot be overridden from outside. It is software: it runs on the equipment if the equipment can be updated, or on a gateway beside it if the equipment is analogue.
Evidence
What remains. Every authenticated interaction produces a signed record — identity, node, action, context, timestamp — verifiable at source and non-repudiable. Aggregated, it composes the signed state of the facility: who is where, what was authorized, what was delivered.