Permit-before-action, fail-closed execution using portable ledger evidence at implementation hooks preceding device I/O, network egress, dispatch, or actuation

A computer-implemented method comprising:

• (a) obtaining, from audit evidence recorded in an Immutable Arbitration Ledger (IAL), an evidence-only bundle comprising at least a permit identifier and a signed-head identifier, wherein gate-predicate evaluation is independent of presence or absence of one or more external artifacts referenced by the audit evidence;
• (b) prior to a requested action, at a configured implementation hook that precedes device I/O, network egress, dispatch, or actuation, using the permit identifier and, when required by a configured validation policy, the signed-head identifier in the evidence-only bundle, verifying that (i) a permit associated with the permit identifier is valid, unexpired, and unrevoked and (ii) evidence required by the configured validation policy is available;
• (c) responsive to successful verification, permitting the requested action to proceed at the configured implementation hook and otherwise causing the requested action to fail closed with a disposition selected from HOLD, QUARANTINE, DENY, and ESCALATE, wherein failure to obtain the evidence required by the configured validation policy, including the permit identifier and, when required by the configured validation policy, the signed-head identifier, or determining that the permit associated with the permit identifier is absent, expired, or revoked, results in DENY, and any HOLD disposition auto-expires absent proof of continuity;
• and
• (d) recording, as audit evidence, a structured record comprising at least an event type, a result code, the disposition, and, when available, the permit identifier and the signed-head identifier, the structured record further comprising an evidence hash.

A non-transitory computer-readable storage medium storing instructions that, when executed by one or more processors, cause the one or more processors to:

• (a) obtain, from audit evidence recorded in an Immutable Arbitration Ledger (IAL), an evidence-only bundle comprising at least a permit identifier and a signed-head identifier, wherein gate-predicate evaluation is independent of presence or absence of one or more external artifacts referenced by the audit evidence;
• (b) prior to a requested action, at a configured implementation hook that precedes device I/O, network egress, dispatch, or actuation, using the permit identifier and, when required by a configured validation policy, the signed-head identifier in the evidence-only bundle, verify that (i) a permit associated with the permit identifier is valid, unexpired, and unrevoked and (ii) evidence required by the configured validation policy is available;
• (c) responsive to successful verification, permit the requested action to proceed at the configured implementation hook and otherwise cause the requested action to fail closed with a disposition selected from HOLD, QUARANTINE, DENY, and ESCALATE, wherein failure to obtain the evidence required by the configured validation policy, including the permit identifier and, when required by the configured validation policy, the signed-head identifier, or determining that the permit associated with the permit identifier is absent, expired, or revoked, results in DENY, and any HOLD disposition auto-expires absent proof of continuity;
• and
• (d) record, as audit evidence, a structured record comprising at least an event type, a result code, the disposition, and, when available, the permit identifier and the signed-head identifier, the structured record further comprising an evidence hash.