ethers.js signing and recover

[novaknole]

Hi @ricmoo

I am trying to do the signing in ethers.js and then verify it in smart contract.

I do the following in my js:

const privateKey = '====';
let wallet = new ethers.Wallet(privateKey);

const messageHash =  ethers.utils.sha256(
    ethers.utils.defaultAbiCoder.encode(["address", "uint256", "uint256"], ["0x94C34FB5025e054B24398220CBDaBE901bd8eE5e", 1, 2])
);
let messageHashBytes = ethers.utils.arrayify(messageHash)
let flatSig = await wallet.signMessage(messageHashBytes);

and in the smart contract, I got:

import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";


contract good {

    using ECDSA for bytes32;
    
    address private _signatureVerifier = 0x94C34FB5025e054B24398220CBDaBE901bd8eE5e;

    function check(uint256 tokenQuantity, bytes calldata signature, uint256 nonce) external view {
        bytes32 messageHash = hashMessage(msg.sender, tokenQuantity, nonce);
        require(messageHash.recover(signature) == _signatureVerifier, "not working");
    }

    function hashMessage(address sender, uint256 tokenQuantity, uint256 nonce) internal pure returns(bytes32) {
        bytes32 hash = keccak256(abi.encodePacked(
            "\x19Ethereum Signed Message:\n32",
            keccak256(abi.encodePacked(sender, tokenQuantity, nonce))));
        return hash;
    }
    
}

now, calling check with tokenQuantity as 1, and nonce as 2, with the flatSign generated with js, it still fails in the require.

Any idea ? thanks a lot in advance.

[novaknole]

@ricmoo

Splendid. Found my answer here #468

You can close this.