Ethereum hashtypeddatav4 Verification problem with the implementation of OpenZeppelin EIP-712
Introduction
Ethereum Virtual Machine (EVM) is based on the implementation of the HashtypedaDA4 contract, which provides a secure means of checking and managing orders. However, a problem was reported where HashtypedaTav4 does not check properly when using the OpenZeppelin EIP-712 implementation. This article aims to investigate and solve this problem.
Background
The HashTypedDatav4 contract uses a hash function to store and check the content of a signed order. The contract is designed in Solidity, which is the programming language used for intelligent Ethereum contracts. The EIP-712 implementation is used to specify the structure and format of the data stored in the contract.
Identification of the problem
The reported problem implies the process of verifying the HashtypedaDataav4 contracts which use the implementation of the EIP-712 of OpenZeppelin. More specifically, when a new command is signed and verified using this implementation, the hash function may not produce any expected signature, leading to an incorrect verification.
Investigation of the code
To investigate more, let’s examine the HashTypedDatav4 contract code and the implementation of OpenZeppelin EIP-712:
Hashtypeddatav4:
`Solidity
Pragma Solidity ^ 0.8,0;
Hashtypeddatav4 contract {
// ...
Verifyorder function (
uint256 [] Memory order,
Bytes32 Public signature
) Public public returns (Bool) {
// ...
}
}
'
EIP-712 implementation:
Solidity
Pragma Solidity ^ 0.7,0; // or 0.8.0
Import "
Import "
AssetMagerbase contract is ERC721, ERC20 {
// ...
function _VERIFYORDERSIGNATURE (
Bytes32 public signature,
Uint256 [] Order of memory
) Unique internal override only payable {
// ...
}
}
'
Resolution
To resolve the problem, we must modify the HashtypedaTav4 contract to use a different hash function that produces an expected signature. A possible solution is to use the Keccak-256 hatching function instead of the default Ethereum hash function.
We can update the HashtypedDatav4 contract as follows:
Solidity
Pragma Solidity ^ 0.8,0;
Hashtypeddatav4 contract {
// ...
Verifyorder function (
uint256 [] Memory order,
Bytes32 Public signature
) Public public returns (Bool) {
// ...
}
function _hashtypeddatav4 (
Uint256 [] memory data,
Bytes32 Public signature
) Internal override not payable {
// Use the Keccak-256 hash function to store the signed command
necessary (data.length> = 20, "the data length typed the hash is less than 20");
bytes32 Hasheddata = Keccak256 (data);
_Updatehash [hasheddata];
}
function _updatehash (bytes32 hasheddata) internal {
// update the hash value in storage of the contract
// ...
}
}
'
Tests and verification
To test the updated hashtypedatav4 contract, we can use a tool like truffle or remix to deploy the contract on the Ethereum network. When verifying an order using the implementation of OpenZeppelin EIP-712, we must expect the hash function to produce an expected signature.
The final code of the HashTypedDatav4 contract resolved is as follows:
` Solidity
Pragma Solidity ^ 0.8,0;
Hashtypeddatav4 contract {
// …
Verifyorder function (
uint256 [] Memory order,
Bytes32 Public signature
) Public public returns (Bool) {
// …