{
    "Function": "recover",
    "File": "contracts/libs/SignatureChecker.sol",
    "Parent Contracts": [],
    "High-Level Calls": [],
    "Internal Calls": [
        "require(bool,string)",
        "require(bool,string)",
        "ecrecover(bytes32,uint8,bytes32,bytes32)",
        "require(bool,string)"
    ],
    "Library Calls": [],
    "Low-Level Calls": [],
    "Code": "function recover(\n    bytes32 hashed,\n    bytes32 r,\n    bytes32 s,\n    uint8 v\n  ) internal pure returns (address) {\n    // https://ethereum.stackexchange.com/questions/83174/is-it-best-practice-to-check-signature-malleability-in-ecrecover\n    // https://crypto.iacr.org/2019/affevents/wac/medias/Heninger-BiasedNonceSense.pdf\n    require(\n      uint256(s) <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0,\n      'Signature: Invalid s parameter'\n    );\n\n    require(v == 27 || v == 28, 'Signature: Invalid v parameter');\n\n    // If the signature is valid (and not malleable), return the signer address\n    address signer = ecrecover(hashed, v, r, s);\n    require(signer != address(0), 'Signature: Invalid signer');\n\n    return signer;\n  }"
}