Security

Threat model & integration rules

PolicyFuse protects the semantic authorization boundary. It does not claim that a policy is wise, fair, lawful, or benevolent, and it does not execute the downstream action.

Core security goals

Exact action binding

An authorization is bound to the canonical action-core digest and cannot be replayed for materially different action data.

Exact consumer binding

Authorization is consumer-specific. is_authorization_current_for compares the expected consumer exactly.

Immutable policy content

Policy fingerprints seal content. Supersession and revocation are lifecycle transitions, not silent mutation.

No permissive uncertainty

Ambiguity becomes UNKNOWN → REPAIR_REQUIRED, never a guessed authorization.

Threat → control

THREATAction substitution

Control: authorization binds exact action digest + consumer.

THREATMalicious leader

Control: validators independently evaluate the same frozen policy and intent, then compare consequential rule states exactly.

THREATMalformed model output

Control: strict schema normalization, complete rule-id coverage, allowed state validation, and canonical vector serialization before state mutation.

THREATValidator divergence

Control: reject the leader result; do not write consequential state. No numeric or semantic tolerance may cross the authorization boundary.

THREATStale authorization

Control: dedicated currentness checks incorporate active policy state, authorization expiry, intent identity, consumer, action digest, and durable bindings.

THREATScope creep into custody

Control: v1 has no payable surface, transfer, escrow, arbitrary downstream write, or hidden execution API.

Rules for downstream developers

Use is_authorization_current_for against the expected consumer and action-core digest.
For irreversible UI/application consequences, read LATEST_FINAL state after finalization.
Maintain application-specific replay or nonce state if your downstream action must be single-use.
Never treat network ACCEPTED as equivalent to finality when your consequence requires durable completion.
Do not infer that latest-created policy means active policy.

PolicyFuse is not an oracle of moral or legal truth. It guarantees the contract-defined binding, lifecycle, and consensus process around a bounded semantic decision.