How to work with _hashTypedDataV4 correctly

Support Contracts
1

This is what the function looks like in the contract:

function extractSigner712(bytes memory signature,
                          address mailTo,
                          string memory mailContents)
                          public view returns (address) {
    bytes32 digest = _hashTypedDataV4(
        keccak256(
            abi.encode(
                keccak256("Mail(address mailTo,string mailContents)"),
                mailTo,
                keccak256(bytes(mailContents))
            )
        )
    );
    address signer = ECDSA.recover(digest, signature);
    return signer;
}

and the test looks like this:

it.only("_hashTypedDataV4 test", async () => {
  const { dao, owner } = await loadFixture(deploy);

  const domain = {
    name: "TestCall",
    version: "1",
    chainId: hre.network.config.chainId,
    verifyingContract: dao.address,
  };
  const types = {
    Mail: [
      { name: "mailTo", type: "address" },
      { name: "mailContents", type: "string" },
    ],
  };

  const value = {
    mailTo: owner.address,
    mailContents: "test message",
  };
  const signature = await owner._signTypedData(domain, types, value);

  const res = await dao.extractSigner712(
    signature,
    value.mailTo,
    value.mailContents
  );
  console.log("res", res);
  expect(res).to.eq(owner.address); // do not match here, why ????
});
2

Issue resolved, found a working example here:

2 Likes
3

No, I hurried with the conclusion, the example is not working.

I created a repository with a simple example:

Please help me understand what is the problem? Thanks.

4

Sorry for the late reply.

The domain as defined in the contract is different from that in the test!

According to the contract you should be specifying name: "test" and version: "1.0".

1 Like
5

Thank you! it works!