Recomputes the EIP-712 typed-data digest for an EIP-3009 TransferWithAuthorization struct, the authorization primitive underneath the x402 payments rail: digest = keccak256(0x19 || 0x01 || domainSeparator || structHash). 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). This node performs no signature recovery and no domain/nonce/window checks; it makes no claim about signature validity, on-chain settlement, or spend.
This node recomputes the exact 32 bytes a wallet signs for an EIP-3009 transfer authorization. It does not verify a signature, recover a signer address, or check domain/nonce/window validity (those are the sibling x402-signer-recovery-verifier and x402-domain-nonce-window-checker nodes). An authorization digest is not a settlement. This node never fetches chain state, never calls a facilitator, and is never a party to a payment.