// SPDX-License-Identifier: MIT pragma solidity ^0.8.0; import "./ECDSA.sol"; import "../Address.sol"; import "../../interfaces/IERC1271.sol"; /** * @dev Signature verification helper: Provide a single mechanism to verify both private-key (EOA) ECDSA signature and * ERC1271 contract sigantures. Using this instead of ECDSA.recover in your contract will make them compatible with * smart contract wallets such as Argent and Gnosis. * * Note: unlike ECDSA signatures, contract signature's are revocable, and the outcome of this function can thus change * through time. It could return true at block N and false at block N+1 (or the opposite). * * _Available since v4.1._ */ library SignatureChecker { function isValidSignatureNow( address signer, bytes32 hash, bytes memory signature ) internal view returns (bool) { if (Address.isContract(signer)) { try IERC1271(signer).isValidSignature(hash, signature) returns (bytes4 magicValue) { return magicValue == IERC1271.isValidSignature.selector; } catch { return false; } } else { return ECDSA.recover(hash, signature) == signer; } } }