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LibSignatureValidator.sol
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LibSignatureValidator.sol
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pragma solidity >=0.4.22 <0.6.0;
contract LibSignatureValidator {
function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
bytes32 r;
bytes32 s;
uint8 v;
// Check the signature length
if (signature.length != 65) {
return (address(0));
}
// Divide the signature in r, s and v variables
// ecrecover takes the signature parameters, and the only way to get them
// currently is to use assembly.
// solium-disable-next-line security/no-inline-assembly
assembly {
r := mload(add(signature, 0x20))
s := mload(add(signature, 0x40))
v := byte(0, mload(add(signature, 0x60)))
}
// Version of signature should be 27 or 28, but 0 and 1 are also possible versions
if (v < 27) {
v += 27;
}
// If the version is correct return the signer address
if (v != 27 && v != 28) {
return (address(0));
} else {
// solium-disable-next-line arg-overflow
return ecrecover(hash, v, r, s);
}
}
}