{
  "tool_id": "art-590-x402-eip712-digest-recomputer",
  "kernel_id": "art-590-x402-eip712-digest-recomputer",
  "display_name": "x402 EIP-712 Digest Recomputer",
  "tool_version": "1.0.0",
  "mandate_type": "compliance_control",
  "purpose": "Recomputes the EIP-712 typed-data digest for an EIP-3009 TransferWithAuthorization struct (the x402 payments rail's underlying authorization primitive) from caller-supplied domain and struct fields only: domain separator, struct hash, and the final keccak256(0x19 || 0x01 || domainSeparator || structHash) digest. All four EIP-712 domain fields (name, version, chainId, verifyingContract) are mandatory inputs and are never defaulted or guessed -- a guessed verifyingContract would defeat the entire point of domain separation. keccak256 comes from the already-vendored, pinned noble-curves/noble-hashes bundle (no new vendoring); the EIP-712/EIP-3009 ABI encoding scheme is implemented directly as public-spec arithmetic on top of it. This node performs no signature recovery and no domain/nonce/window checks -- it makes no claim about signature validity, on-chain settlement, or spend. Zero network calls; never a facilitator, proxy, or settlement relay. Golden vectors are cross-checked against externally published references (the EIP-712 spec's own domain-separator worked example, and Circle's production TransferWithAuthorization typehash), not round-trip self-tests alone.",
  "control_description": "Recomputes the EIP-712 typed-data digest for an EIP-3009 TransferWithAuthorization struct (the x402 payments rail's underlying authorization primitive) from caller-supplied domain and struct fields only: domain separator, struct hash, and the final keccak256(0x19 || 0x01 || domainSeparator || structHash) digest. All four EIP-712 domain fields (name, version, chainId, verifyingContract) are mandatory inputs and are never defaulted or guessed -- a guessed verifyingContract would defeat the entire point of domain separation. keccak256 comes from the already-vendored, pinned noble-curves/noble-hashes bundle (no new vendoring); the EIP-712/EIP-3009 ABI encoding scheme is implemented directly as public-spec arithmetic on top of it. This node performs no signature recovery and no domain/nonce/window checks -- it makes no claim about signature validity, on-chain settlement, or spend. Zero network calls; never a facilitator, proxy, or settlement relay. Golden vectors are cross-checked against externally published references (the EIP-712 spec's own domain-separator worked example, and Circle's production TransferWithAuthorization typehash), not round-trip self-tests alone.",
  "declared_inputs": [],
  "declared_outputs": [
    "art-591-x402-signer-recovery-verifier"
  ],
  "kernel_digest": "sha256:62dbc12bf0d0a66b089587f7c30ca10fa8ec5e33bed5d8867d9d7dfdba7b0b15",
  "trust_label": "independently verified: zkVM execution proof (risc0/groth16-bn254)",
  "data_vintage": "2026-08-20",
  "last_validated": "2026-08-20",
  "conformance_fixtures_vendored": true,
  "compute_proof_ready": "ready",
  "wave": 99,
  "source_url": "https://ainumbers.co/chaingraph/art-590-x402-eip712-digest-recomputer.html",
  "generated_at": "2026-08-22T17:52:19.663Z"
}