Function: pay(PaymentVoucher calldata voucher, bytes calldata signature)

This function processes payment for off-chain orders using signed vouchers. It supports both ETH and ERC-20 token payments with signature verification and payment-ID replay protection.

Inputs

• voucher.buyer

  • Control: Full.

  • Constraints: Must match msg.sender (checked via _verifyBuyerMatchesSender()).

  • Impact: Ensures only the designated buyer can execute the payment, preventing unauthorized payment execution.

• voucher.token

  • Control: Full.

  • Constraints: N/A.

  • Impact: Specifies payment token (address(0) for ETH, ERC-20 address for tokens).

• voucher.amount

  • Control: Full.

  • Constraints: Must match msg.value for ETH payments or be transferred from buyer for ERC-20.

  • Impact: Ensures the payment amount matches the voucher specification, preventing underpayment attacks.

• voucher.voucherExpiration

  • Control: Full.

  • Constraints: Must be greater than the current block timestamp (checked via _verifyNotExpiredVoucher()).

  • Impact: Prevents execution of expired vouchers, ensuring time-sensitive payment conditions.

• voucher.paymentId

  • Control: Full.

  • Constraints: Must be unique and not previously used (checked via usedPaymentIdHashes mapping).

  • Impact: Prevents replay attacks by ensuring each payment voucher can only be used once.

• voucher.orderId

  • Control: Full.

  • Constraints: Included in signature hash but no direct validation.

  • Impact: Links payment to specific order for off-chain tracking and verification.

• signature

  • Control: Full.

  • Constraints: ECDSA signature verification via _verifySignature() to ensure voucher was signed by an authorized signer.

  • Impact: Ensures voucher authenticity and prevents unauthorized voucher creation.

Branches and code coverage (including function calls)

Intended branches

Negative behavior