Documentation Index
Fetch the complete documentation index at: https://docs.abs.xyz/llms.txt
Use this file to discover all available pages before exploring further.
Since smart contract accounts don’t have a way to validate signatures like an EOA,
it is also recommended that you implement EIP-1271
for your smart contract accounts.
This EIP provides a standardized way for smart contracts to verify whether a signature
is valid for a given message.
EIP-1271 Specification
EIP-1271 specifies a single function, isValidSignature, that can contain any arbitrary logic
to validate a given signature and largely depends on how you have implemented your smart contract account.
contract ERC1271 {
// bytes4(keccak256("isValidSignature(bytes32,bytes)"))
bytes4 constant internal MAGICVALUE = 0x1626ba7e;
/**
* @dev Should return whether the signature provided is valid for the provided hash
* @param _hash Hash of the data to be signed
* @param _signature Signature byte array associated with _hash
*
* MUST return the bytes4 magic value 0x1626ba7e when function passes.
* MUST NOT modify state (using STATICCALL for solc < 0.5, view modifier for solc > 0.5)
* MUST allow external calls
*/
function isValidSignature(
bytes32 _hash,
bytes memory _signature)
public
view
returns (bytes4 magicValue);
}
OpenZeppelin Implementation
OpenZeppelin provides a way to verify signatures for different account implementations that
you can use in your smart contract account.
Install the OpenZeppelin contracts library:
npm install @openzeppelin/contracts
isValidSignature function in your smart contract account:
import {IAccount, ACCOUNT_VALIDATION_SUCCESS_MAGIC} from "./interfaces/IAccount.sol";
import { SignatureChecker } from "@openzeppelin/contracts/utils/cryptography/SignatureChecker.sol";
contract MyAccount is IAccount {
using SignatureChecker for address;
function isValidSignature(
address _address,
bytes32 _hash,
bytes memory _signature
) public pure returns (bool) {
return _address.isValidSignatureNow(_hash, _signature);
}
}
Verifying Signatures
On the client, you can use zksync-ethers to
verify signatures for your smart contract account using either:
isMessageSignatureCorrect for verifying a message signature.isTypedDataSignatureCorrect for verifying a typed data signature.
export async function isMessageSignatureCorrect(address: string, message: ethers.Bytes | string, signature: SignatureLike): Promise<boolean>;
export async function isTypedDataSignatureCorrect(
address: string,
domain: TypedDataDomain,
types: Record<string, Array<TypedDataField>>,
value: Record<string, any>,
signature: SignatureLike
): Promise<boolean>;
