PaymentVerifierRegistry

Registry for managing payment methods, verifiers, and supported currencies

Overview

The PaymentVerifierRegistry is a central registry contract that manages the configuration of supported payment methods, their associated verifier contracts, and the currencies each payment method supports. It provides a flexible system for adding and managing different payment methods (like Venmo, Revolut, etc.) along with their specific verification logic.

Contract Location: contracts/registries/PaymentVerifierRegistry.sol

Purpose

The PaymentVerifierRegistry serves several critical functions:

• Payment Method Management: Register and manage different off-chain payment methods
• Verifier Assignment: Associate each payment method with its specific verifier contract
• Currency Support: Define which currencies (USD, EUR, etc.) each payment method supports
• Centralized Configuration: Provide a single source of truth for payment method configurations

Key Components

State Variables

mapping(bytes32 => PaymentMethodConfig) public store;
bytes32[] public paymentMethods;

• store: Maps payment method hashes to their configuration (verifier address and supported currencies)
• paymentMethods: Array of all registered payment method identifiers

PaymentMethodConfig Struct

struct PaymentMethodConfig {
    bool initialized;
    address verifier;
    mapping(bytes32 => bool) isCurrency;
    bytes32[] currencies;
}

Stores the complete configuration for a payment method including its verifier contract and supported currencies.

Core Functions

Adding a Payment Method

function addPaymentMethod(
    bytes32 _paymentMethod,
    address _verifier,
    bytes32[] calldata _currencies
) external onlyOwner

Registers a new payment method with its verifier and initial set of supported currencies.

Parameters:

• _paymentMethod: Hash of the payment method name (lowercase, e.g., keccak256("venmo"))
• _verifier: Address of the verifier contract for this payment method
• _currencies: Array of currency code hashes (e.g., keccak256("USD"))

Requirements:

• Payment method must not already exist
• Verifier address cannot be zero
• At least one currency must be provided

Emits: PaymentMethodAdded(bytes32 indexed paymentMethod)

Reference: contracts/registries/PaymentVerifierRegistry.sol:44

Removing a Payment Method

function removePaymentMethod(bytes32 _paymentMethod) external onlyOwner

Removes a payment method and all its associated configuration.

Reference: contracts/registries/PaymentVerifierRegistry.sol:68

Managing Currencies

function addCurrencies(bytes32 _paymentMethod, bytes32[] calldata _currencies) public onlyOwner
function removeCurrencies(bytes32 _paymentMethod, bytes32[] calldata _currencies) external onlyOwner

Add or remove supported currencies for a specific payment method.

Reference: contracts/registries/PaymentVerifierRegistry.sol:88 and :102

View Functions

Query Payment Methods

function isPaymentMethod(bytes32 _paymentMethod) external view returns (bool)
function getPaymentMethods() external view returns (bytes32[] memory)
function getVerifier(bytes32 _paymentMethod) external view returns (address)

Query registered payment methods and their verifiers.

Query Currencies

function isCurrency(bytes32 _paymentMethod, bytes32 _currencyCode) external view returns (bool)
function getCurrencies(bytes32 _paymentMethod) external view returns (bytes32[] memory)

Check currency support for specific payment methods.

Integration with Core Contracts

Orchestrator

The Orchestrator contracts (Orchestrator.sol and OrchestratorV2.sol) reference the PaymentVerifierRegistry to:

• Validate that intents use registered payment methods
• Retrieve the appropriate verifier contract for payment verification
• Ensure the requested currency is supported by the payment method

Reference: contracts/Orchestrator.sol:83

EscrowV2

EscrowV2 uses the registry to validate payment method configurations when creating deposits.

Reference: contracts/EscrowV2.sol:128

Payment Verifiers

Verifier contracts registered in this registry are called to validate ZK proofs of off-chain payments.

Access Control

Owner-Only Functions

All state-modifying functions are restricted to the contract owner:

• addPaymentMethod()
• removePaymentMethod()
• addCurrencies()
• removeCurrencies()

Access Control Pattern: OpenZeppelin’s Ownable with onlyOwner modifier

View Functions

All view functions are publicly accessible, allowing any contract or user to query payment method configurations.

Events

event PaymentMethodAdded(bytes32 indexed paymentMethod);
event PaymentMethodRemoved(bytes32 indexed paymentMethod);
event CurrencyAdded(bytes32 indexed paymentMethod, bytes32 indexed currencyCode);
event CurrencyRemoved(bytes32 indexed paymentMethod, bytes32 indexed currencyCode);

These events enable off-chain monitoring of payment method configuration changes.

Usage Example

Adding a new payment method:

// Calculate payment method and currency hashes
bytes32 venmoHash = keccak256("venmo");
bytes32[] memory currencies = new bytes32[](2);
currencies[0] = keccak256("USD");
currencies[1] = keccak256("EUR");

// Add payment method with verifier address
paymentVerifierRegistry.addPaymentMethod(
    venmoHash,
    venmoVerifierAddress,
    currencies
);

Security Considerations

1. Owner Control: Only the owner can modify payment method configurations, providing strong governance over supported payment methods
2. Validation: All inputs are validated to prevent zero addresses and duplicate entries
3. Immutable After Addition: Payment method verifiers cannot be changed after addition (must remove and re-add)
4. Hash-Based Identification: Using hashes instead of strings provides gas efficiency and standardization

Related Contracts

• Orchestrator - Uses registry to validate payment methods
• EscrowV2 - References registry for deposit creation
• Payment Verifiers - Contracts registered in this registry for proof verification