In evidentiary contexts, chain-of-custody is the documentation that shows who held an item, when, and under what authority — preserved unbroken from origin to use. EXOCHAIN extends that discipline to autonomous action.
The blockchain mechanism preserves order. Each block extends the prior block's hash, and the order in which receipts are committed cannot be revised after finality without detection.
Chain-of-custody preserves responsibility. Every action references the credential that authorized it, the principal that issued the credential, and the consent, policy, and revocation state in effect when the action occurred.
Revocation is a first-class operation on the credential graph. When an issuer revokes an AVC, every credential derived from it inherits the revocation. Already-issued receipts remain as evidence of past authorization; future actions under the revoked credential fail-closed at validation.