action-ref-verify

Conformance verifier for x402 post-settlement action_ref fields.

Re-derives action_ref using JCS (RFC 8785) + SHA-256 and verifies it matches the claimed hash. Context: x402-foundation/x402#2332.

Usage

npm install
node verify.mjs vectors/0001-giskard-baseline.json

Or pipe:

echo '{"action_ref":"fdd7f8...","preimage":{"agent_id":"x","action_type":"y","scope":"z","timestamp":"2025-05-18T11:40:31.000Z"}}' | node verify.mjs

Hosted API

Submit receipts and get conformance verdicts without running the CLI:

curl -X POST https://verify.crestsystems.ai/v1/verify \
  -H "Content-Type: application/json" \
  -d '{"action_ref":"<sha256>","preimage":{"action_type":"...","agent_id":"...","scope":"...","timestamp":"..."}}'

Returns a signed verdict with a public permalink at verify.crestsystems.ai/v1/verdict/:id.

Canonical derivation

action_ref = SHA-256(JCS(preimage_object))

Where JCS is JSON Canonicalization Scheme (RFC 8785):

• Keys sorted lexicographically (alphabetical for ASCII)
• No whitespace
• Field names are opaque bytes (load-bearing in the digest)

Two timestamp encodings are supported:

• timestamp_ms (integer, epoch milliseconds) -- per the original #2332 preimage spec
• timestamp (string, RFC 3339 UTC) -- legacy encoding from early verifier versions

These produce different digests. The field name is part of the JCS canonical output. See vector 0009 for a worked proof.

Fixture format

{
  "action_ref": "<SHA-256 hex>",
  "preimage": {
    "action_type": "sanctions_screen",
    "agent_id": "did:web:agent-7.example.com",
    "scope": "counterparty-due-diligence",
    "timestamp_ms": 1747728000000
  },
  "payment_hash": "<Base tx hash (optional)>",
  "spec": "action-ref-v1-jcs-sha256"
}

What it checks

1. Re-derives action_ref as SHA-256(JCS(preimage)) and compares to claimed hash
2. Verifies payment_hash is present (if provided)
3. Verifies spec field is declared

Returns PASS or FAIL with detailed check results.

Conformance vectors

Vector	Implementation	Source	Status
0001-giskard-baseline	argentum-core	#2332	PASS
0002-ms-precision-trap	crest-adversarial	v0.2.0	FAIL (by design)
0003-trailing-whitespace	crest-adversarial	v0.2.0	FAIL (by design)
0004-extra-field-ignored	crest-adversarial	v0.2.0	PASS
0005-key-order-resilience	crest-adversarial	v0.2.0	PASS
0006-rfc8785-negative-zero	rfc8785-appendix-b	v0.2.0	PASS
0007-rfc8785-key-sorting-stress	rfc8785-appendix-b	v0.2.0	PASS
0008-x402-2357-shared-fixture	crest-interop	#2357	PASS
0009-field-name-load-bearing	crest-adversarial	v0.3.0	FAIL (by design)

See CONFORMANCE_INTAKE.md for submission format and publication policy.

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