Signature Validation

Your project can start preparing for native AA support. We highly encourage you to do so, since it will allow you to onboard hundreds of thousands of users (many new Wallets are smart accounts by default, providing way smoother experience for users). We expect that in the future even more users will switch to smart wallets.

One of the most notable differences between various types of accounts to be built is different signature schemes. We expect accounts to support the EIP-1271 standard.

The @openzeppelin/contracts/utils/cryptography/SignatureChecker.sol library provides a way to verify signatures for different account implementations. We strongly encourage you to use this library whenever you need to check that a signature of an account is correct.

Adding the library to your project

npm add @openzeppelin/contracts

Example of using the library

pragma solidity ^0.8.0;

import { SignatureChecker } from "@openzeppelin/contracts/utils/cryptography/SignatureChecker.sol";

contract TestSignatureChecker {
    using SignatureChecker for address;

    function isValidSignature(
        address _address,
        bytes32 _hash,
        bytes memory _signature
    ) public pure returns (bool) {
        return _address.isValidSignatureNow(_hash, _signature);
    }
}

Verifying AA signatures

It is also not recommended to use ethers.js library to verify user signatures.

Our SDK provides two methods with its utils to verify the signature of an account:

export async function isMessageSignatureCorrect(address: string, message: ethers.Bytes | string, signature: SignatureLike): Promise<boolean>;

export async function isTypedDataSignatureCorrect(
  address: string,
  domain: TypedDataDomain,
  types: Record<string, Array<TypedDataField>>,
  value: Record<string, any>,
  signature: SignatureLike
): Promise<boolean>;

Currently these methods only support verifying ECDSA signatures, but very soon they will support EIP1271 signature verification as well.

Both of these methods return true or false depending on whether the message signature is correct.