eth_sign.md

eth_sign

Description

The eth_sign issue arises due to the fact that VeChain and Ethereum use different hash functions, more information on this subject here. This failure is justifiable as it is a design difference between the two chains. To fix the failing tests, we imported Ethereum's hash function and replaced the eth_sign method with one that generates signatures using the required hash function.

The following changes we made:

In compatProvider.ts

In web3-providers-connex/src/compatProvider.ts we changed the error response returned to the following:

.catch(err => callback(err, {
				id: payload.id,
				jsonrpc: '2.0',
				error: err
			}));

In provider.ts

In web3-providers-connex/src/provider.ts we imported hashEthMessage and bufferToHex from utils.js

import { hexToNumber, getErrMsg, toSubscription, toHex, hashEthMessage, bufferToHex } from './utils';

We also added the method eth_sign in the method map

this._methodMap['eth_sign'] = this._sign;

and defined the function in the same file

private _sign = async (params: any) => {
		if (!this.wallet || this.wallet.list.length === 0) {
			throw new Error("no wallet specified");
		}

		const address = params[0];
		const message = params[1];

		const key = this.wallet.list.find((key) => key.address == address);

		if (key === undefined) {
			throw new Error(`key undefined for address ${address}`)
		}

		const hash = hashEthMessage(message);

		if (hash === undefined) {
			throw new Error("undefined hash");
		}

		const hashStriped = hash?.substring(2);
		const buf = Buffer.from(hashStriped!, 'hex');

		const signature = await key.sign(buf);
		signature[64] += 27;

		return bufferToHex(signature);
	}

In utils.ts

In web3-providers-connex/src/utils.ts we imported keccak256 from 'thor-devkit'.

import { abi, keccak256, Transaction } from 'thor-devkit';

Then we defined two new functions hashEthMessage that hashes a string with Ethereum's hash function and a helper function bufferToHex.

export function bufferToHex(buf: Buffer) : string {
	return '0x' + buf.toString('hex');
}

export function hashEthMessage(data: string) : string {
	const messageHex = web3Utils.isHexStrict(data) ? data : web3Utils.utf8ToHex(data);
	const messageBytes = web3Utils.hexToBytes(messageHex);
	const messageBuffer = Buffer.from(messageBytes);
	const preamble = '\x19Ethereum Signed Message:\n' + messageBytes.length;
	const preambleBuffer = Buffer.from(preamble);
	const ethMessage = Buffer.concat([preambleBuffer, messageBuffer]);
	return bufferToHex(keccak256(ethMessage));

In getChainId.test.ts

The final change was in web3-providers-connex/test/web3/getChainId.test.ts where we replaced the main-net URL with the local instance of thor instead.

const net = new SimpleNet("http://127.0.0.1:8669");

Contracts Affected

Contract Name
SignatureChecker