ERC-8419: Know-Your-Agent (KYA) Framework

What it is

A Rev2 review comment on ERC-8419 (Know-Your-Agent), reducing all the framework's gaps to one invariant: every value or transformation capable of changing a KYA decision must either be committed by the identity of the object evaluated, or be explicitly declared live/external and excluded from any claim of complete policy satisfaction. The comment gives concrete hash constructions and a regression suite, which the catalog summary does not carry.

The concrete fixes proposed

• Policy identity binds the executable projection. Today registerPolicyWithRules(policyURI, policyHash, allOf) derives policyId from owner, policyHash, and nonce — nothing proves the on-chain allOf rules match the committed document. Add a canonical rulesHash = H(canonical executable rules) and make policyId = H(owner, policyHash, rulesHash, nonce).
• Bridge configuration identity. Adding the bridge address to requestHash fixed bridge ambiguity but not config ambiguity: the same assertion resolving to level 2 yields ERC-8004 response 100 under responseMap [0,50,100] vs 70 under [0,20,70], with the request/assertion/response-commitment all unchanged. Bind configHash = H(schemeId, trustedIssuers, responseMap) into request and response provenance.
• Epoch authority MUST. Keep current = floor(block.timestamp / epochSeconds) with current - epochGrace <= epoch <= current. The prover MUST NOT control the epoch; the mechanism (block ranges, finalized periods) is profile-defined, but the authority is system/verifier-determined.
• Tag collision. The bridge uses "kya:" + first 8 hex chars of schemeId — only a 32-bit discriminator, so two schemes can collide. Use the complete schemeId or another collision-resistant identifier.
• Verifier semantic immutability. A PROVED scheme commits a verifier address; an upgradeable proxy keeps the address constant while verify() changes. Make it normative that any dependency capable of changing proof acceptance for an existing schemeId stays semantically immutable — semantic changes require a successor scheme.
• Domain separation MUST (chain + registry) for canonical ZK admission; portability across registries becomes an explicit profile, not accidental nullifier replay.

Regression cases to add

Six named tests gate closure: policy-projection mismatch, controller transfer, bridge-config mutation, verifier semantic mutation, tag collision, cross-registry replay.

Caveats

This is a design-review comment on a proposal, not a disclosed vulnerability in deployed code — no CVE, no shipped contract. The author explicitly declines two design options (per-assertion binding kind; a heavier optional evaluator) and would instead precisely define the supported on-chain projection (top-level allOf, ordered-level schemes, issuer constraints) and reject anything outside it.