How to verify signature in NodeJs via web3j?

Question

I am sending an EIP_712 signature from metamask to the java backend (web3j) and I need to verify it on backend java application.

In this topics it is discussed the support of EIP-712 in java (web3j):

• https://github.com/web3j/web3j/issues/898

• https://github.com/web3j/web3j/pull/911

but it does not have any documentation or example for how to do it!

Answer 1

To verify a signature via web3, you can use the web3.eth.accounts.recover method. Here's how I did it

const Web3 = require('web3');
const web3 = new Web3('https://mainnet.infura.io/v3/your-project-id'); // Replace with your own Infura project ID or URL

const signature = '...'; // Replace with the signature you want to verify
const message = '...'; // Replace with the original message that was signed
const address = '...'; // Replace with the expected signer address

const recoveredAddress = web3.eth.accounts.recover(message, signature);

if (recoveredAddress.toLowerCase() === address.toLowerCase()) {
  console.log('Signature is valid!');
} else {
  console.log('Signature is invalid.');
}

Hope that works for you