OpenChainGraph Suite · ART-592 · x402 / EIP-3009 Crypto Primitive
x402 Domain & Nonce Window Checker
Checks an EIP-3009 TransferWithAuthorization's domain separation against a caller-supplied expectation, and its replay-defense-adjacent fields. expected_chain_id/expected_verifying_contract are mandatory inputs, distinct from the chainId/verifyingContract actually baked into the signed domain. A mismatch on either is a hard refuse, never a soft warning. Also checks the validAfter/validBefore window against a caller-supplied now_unix, and the nonce's format (bytes32, non-zero).
EIP-712 / EIP-3009Domain separation, hard refuse on mismatchNo signature recovery, no digest recompute
🔒 All inputs are processed locally in your browser. No data is transmitted. Do not enter real personal data — use synthetic or anonymised inputs only.
What This Does and Does Not Prove
This node compares caller-supplied fields against each other and against a caller-supplied reference time. It does not recompute a signature digest or recover a signer (those are the sibling x402-eip712-digest-recomputer and x402-signer-recovery-verifier nodes), and it never queries a chain. On-chain nonce uniqueness is enforced by the token contract at settlement time, not by this verifier. This tool confirms the authorization is well-formed and not self-reported as already used. It cannot confirm the nonce has never been spent on-chain.
Expected Domain (mandatory policy parameters, never defaulted)
Distinct from the domain actually baked into the signature below. Never inferred from it. A mismatch on either field is a hard refuse (SPEC-X402-CRYPTO-CORE-1-2026-08-09.md §6).
Signed Domain (the fields actually baked into the signature)
Window & Nonce
This kernel never queries a chain. Supply this only if the caller already checked its own on-chain/off-chain record.