Ethereum HashTypedDataV4 verification problem when deploying OpenZeppelin EIP-712
Introduction
The Ethereum Virtual Machine (EVM) is based on an implementation of the HashTypedDataV4 contract, which provides a secure way to verify and manage orders. However, an issue has been reported where HashTypedDataV4 does not correctly validate against the OpenZeppelin EIP-712 implementation. The purpose of this article is to study and solve this problem.
Background
The HashTypedDataV4 contract uses a hash function to store and verify the contents of the signed order. The contract is written in the Solidity programming language, which is used for Ethereum smart contracts. The EIP-712 implementation is used to specify the structure and format of the data stored in the contract.
Identifying the problem
The reported issue is related to the validation process of HashTypedDataV4 contracts using OpenZeppelin’s EIP-712 implementation. In particular, when a new order is signed and verified using this implementation, the hash function may not produce the expected signature, which will lead to incorrect verification.
Learning the code
For further study, let’s look at the HashTypedDataV4 contract code and the OpenZeppelin EIP-712 implementation:
HashTypedDataV4:
pragma reliability ^0.8.0;
contract HashTypedDataV4 {
//...
function verifyOrder(
uint256[] memory order,
public signature bytes32
) public netreturn(bool) {
//...
}
}
Implementation of EIP-712:
pragma reliability ^0.7.0; // or 0.8.0
import "
import "
contract "AssetManagerBase" - ERC721, ERC20 {
//...
function _verifyOrderSignature(
public signature bytes32,
uint256[] memory order
) internal redefinition is not subject to payment onlyOwner {
//...
}
}
Permission
To fix the problem, we need to modify the HashTypedDataV4 contract to use a second hash function that produces the expected signature. One possible solution is to use the Keccak-256 hash function instead of the default Ethereum hash function.
We can update the HashTypedDataV4 contract as follows:
pragma reliability ^0.8.0;
contract HashTypedDataV4 {
//...
function verifyOrder(
uint256[] memory order,
public signature bytes32
) public netreturn(bool) {
//...
}
function _hashTypedDataV4(
uint256[] memory data
public signature bytes32
) internal redetermination is not subject to payment {
// Use the Keccak-256 hash function to store the signed order
Requirement(data.length >= 20, "Hash type data length is less than 20");
bytes32 hashedData = hash256(data);
_updateHash[hashedData];
}
function _updateHash(bytes32 hashedData) internal {
// Update the hash value in the contract repository
//...
}
}
Testing and checking
To test the updated HashTypedDataV4 contract, we can use a tool like Truffle or Remix to deploy the contract on the Ethereum network. When verifying an order using the OpenZeppelin EIP-712 implementation, you should expect the hash function to produce the expected signature.
The final code for the resolved HashTypedDataV4 contract looks like this:
“` strength
pragma reliability ^0.8.0;
contract HashTypedDataV4 {
//…
function verifyOrder(
uint256[] memory order,
public signature bytes32
) public netreturn(bool) {
//…
