MetaCoin.sol

pragma solidity >=0.4.25 <0.6.0;

import "openzeppelin-solidity/contracts/cryptography/ECDSA.sol";

// This is just a simple example of a coin-like contract.
// It is not standards compatible and cannot be expected to talk to other
// coin/token contracts. If you want to create a standards-compliant
// token, see: https://github.com/ConsenSys/Tokens. Cheers!

contract MetaCoin {
	function recover(bytes32 _digest, bytes memory signature) public view returns(address) {
		bytes32 prefixed = ECDSA.toEthSignedMessageHash(_digest);
		return ECDSA.recover(prefixed, signature);
	}
}