I can't run recoverPublicKey method correctly

[fedecastelli]

Hello,

I'm creating a test to retrieve the public key that signed the original message. It should match the publicKey linked to my predefined privateKey, but it doesn't match, and I'm currently unable to resolve it.

This is the test I wrote:

import {privateKeyToAccount} from 'viem/accounts';
import {keccak256, recoverPublicKey, toHex} from "viem";

const PRIVATE_KEY = '0x9fea44d148411b352a0795a115db558b9524b31a310a71fc657e1cd7f6d3e8d7';

it('Get signature public key', async () => {
  const messageToBeSigned = 'Message to be signed';
  // load account using hardcoded PRIVATE KEY
  const account = privateKeyToAccount(PRIVATE_KEY);
  // generate the signature of the message
  const signature = await account.signMessage({
    message: toHex(messageToBeSigned),
  });
  // get the public key that has signed the message 
  const publicKeySigner = await recoverPublicKey({
    hash: toHex(messageToBeSigned),
    signature: signature,
  });
  // verify that the publicKeySigner is equal to be public key associated with the account loaded
  expect(publicKeySigner).toStrictEqual(account.publicKey); // error
});

The strange thing is if I add the method to verify the message (using verifyMessage from import { verifyMessage } from 'viem', it says that the address correctly signed the message.

const isValidSignature = await verifyMessage({
    address: account.address,
    message: toHex(messageToBeSigned),
    signature: signature,
});
expect(isValidSignature).toStrictEqual(true);

Could someone help me with my issue?

[jxom]

Are you using Jest? Does this also happen with Vitest?

[fedecastelli]

I've all my tests written with Jest. In the meantime I created a playground and I had the same error. Do you want me to create this test with Vitest?

[fedecastelli]

I found the error in the test above. The problem is that I'm calling the recoverPublicKey method using the hex of my original message instead of using the hash. I was using the hex value also signing the message (I removed it and now I'm using the original message).

I updated the method using the hash and it's working. This is the updated code:

import {privateKeyToAccount} from 'viem/accounts';
import {keccak256, recoverPublicKey, toHex, hashMessage} from "viem";

const PRIVATE_KEY = '0x9fea44d148411b352a0795a115db558b9524b31a310a71fc657e1cd7f6d3e8d7';

it('Get signature public key', async () => {
  const messageToBeSigned = 'Message to be signed';
  // load account using hardcoded PRIVATE KEY
  const account = privateKeyToAccount(PRIVATE_KEY);
  // generate the signature of the message
  const signature = await account.signMessage({
    message: messageToBeSigned,
  });
  // get the public key that has signed the message 
  const publicKeySigner = await recoverPublicKey({
    hash: hashMessage(messageToBeSigned),
    signature: signature,
  });
  // verify that the publicKeySigner is equal to be public key associated with the account loaded
  expect(publicKeySigner).toStrictEqual(account.publicKey); 
});