Deploying a multisig smart account
This example covers the configuration and deployment of a multisig smart account.
Steps Overview
- Specify the owners of the multisig account
- Execute the deployment script
Contracts
For this example, we will use 3 contracts:
AAFactory- A factory contract that will be used to deploy the multisig account.TwoUserMultisig- A multisig account with 2 owners.DeployMultisig- A script to deploy the multisig account through the factory.
AAFactory
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;
import "@era-contracts/Constants.sol";
import "@era-contracts/libraries/SystemContractsCaller.sol";
contract AAFactory {
bytes32 public aaBytecodeHash;
constructor(bytes32 _aaBytecodeHash) {
aaBytecodeHash = _aaBytecodeHash;
}
function deployAccount(
bytes32 salt,
address owner1,
address owner2
) external returns (address accountAddress) {
(bool success, bytes memory returnData) = SystemContractsCaller
.systemCallWithReturndata(
uint32(gasleft()),
address(DEPLOYER_SYSTEM_CONTRACT),
uint128(0),
abi.encodeCall(
DEPLOYER_SYSTEM_CONTRACT.create2Account,
(
salt,
aaBytecodeHash,
abi.encode(owner1, owner2),
IContractDeployer.AccountAbstractionVersion.Version1
)
)
);
require(success, "Deployment failed");
(accountAddress) = abi.decode(returnData, (address));
}
}
TwoUserMultisig
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;
import "@era-contracts/interfaces/IAccount.sol";
import "@era-contracts/libraries/TransactionHelper.sol";
import "@era-contracts/Constants.sol";
import "@era-contracts/libraries/SystemContractsCaller.sol";
import "@openzeppelin/contracts/interfaces/IERC1271.sol";
import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
contract TwoUserMultisig is IAccount, IERC1271 {
// to get transaction hash
using TransactionHelper for Transaction;
// state variables for account owners
address public owner1;
address public owner2;
bytes4 constant EIP1271_SUCCESS_RETURN_VALUE = 0x1626ba7e;
modifier onlyBootloader() {
require(
msg.sender == BOOTLOADER_FORMAL_ADDRESS,
"Only bootloader can call this function"
);
// Continue execution if called from the bootloader.
_;
}
constructor(address _owner1, address _owner2) {
owner1 = _owner1;
owner2 = _owner2;
}
function validateTransaction(
bytes32,
bytes32 _suggestedSignedHash,
Transaction calldata _transaction
) external payable override onlyBootloader returns (bytes4 magic) {
return _validateTransaction(_suggestedSignedHash, _transaction);
}
function _validateTransaction(
bytes32 _suggestedSignedHash,
Transaction calldata _transaction
) internal returns (bytes4 magic) {
// Incrementing the nonce of the account.
// Note, that reserved[0] by convention is currently equal to the nonce passed in the transaction
SystemContractsCaller.systemCallWithPropagatedRevert(
uint32(gasleft()),
address(NONCE_HOLDER_SYSTEM_CONTRACT),
0,
abi.encodeCall(
INonceHolder.incrementMinNonceIfEquals,
(_transaction.nonce)
)
);
bytes32 txHash;
// While the suggested signed hash is usually provided, it is generally
// not recommended to rely on it to be present, since in the future
// there may be tx types with no suggested signed hash.
if (_suggestedSignedHash == bytes32(0)) {
txHash = _transaction.encodeHash();
} else {
txHash = _suggestedSignedHash;
}
// The fact there is enough balance for the account
// should be checked explicitly to prevent user paying for fee for a
// transaction that wouldn't be included on Ethereum.
uint256 totalRequiredBalance = _transaction.totalRequiredBalance();
require(
totalRequiredBalance <= address(this).balance,
"Not enough balance for fee + value"
);
if (
isValidSignature(txHash, _transaction.signature) ==
EIP1271_SUCCESS_RETURN_VALUE
) {
magic = ACCOUNT_VALIDATION_SUCCESS_MAGIC;
} else {
magic = bytes4(0);
}
}
function executeTransaction(
bytes32,
bytes32,
Transaction calldata _transaction
) external payable override onlyBootloader {
_executeTransaction(_transaction);
}
function _executeTransaction(Transaction calldata _transaction) internal {
address to = address(uint160(_transaction.to));
uint128 value = Utils.safeCastToU128(_transaction.value);
bytes memory data = _transaction.data;
if (to == address(DEPLOYER_SYSTEM_CONTRACT)) {
uint32 gas = Utils.safeCastToU32(gasleft());
// Note, that the deployer contract can only be called
// with a "systemCall" flag.
SystemContractsCaller.systemCallWithPropagatedRevert(
gas,
to,
value,
data
);
} else {
bool success;
assembly {
success := call(
gas(),
to,
value,
add(data, 0x20),
mload(data),
0,
0
)
}
require(success);
}
}
function executeTransactionFromOutside(
Transaction calldata _transaction
) external payable {
bytes4 magic = _validateTransaction(bytes32(0), _transaction);
require(magic == ACCOUNT_VALIDATION_SUCCESS_MAGIC, "NOT VALIDATED");
_executeTransaction(_transaction);
}
function isValidSignature(
bytes32 _hash,
bytes memory _signature
) public view override returns (bytes4 magic) {
magic = EIP1271_SUCCESS_RETURN_VALUE;
if (_signature.length != 130) {
// Signature is invalid anyway, but we need to proceed with the signature verification as usual
// in order for the fee estimation to work correctly
_signature = new bytes(130);
// Making sure that the signatures look like a valid ECDSA signature and are not rejected rightaway
// while skipping the main verification process.
_signature[64] = bytes1(uint8(27));
_signature[129] = bytes1(uint8(27));
}
(
bytes memory signature1,
bytes memory signature2
) = extractECDSASignature(_signature);
if (
!checkValidECDSASignatureFormat(signature1) ||
!checkValidECDSASignatureFormat(signature2)
) {
magic = bytes4(0);
}
address recoveredAddr1 = ECDSA.recover(_hash, signature1);
address recoveredAddr2 = ECDSA.recover(_hash, signature2);
// Note, that we should abstain from using the require here in order to allow for fee estimation to work
if (recoveredAddr1 != owner1 || recoveredAddr2 != owner2) {
magic = bytes4(0);
}
}
// This function verifies that the ECDSA signature is both in correct format and non-malleable
function checkValidECDSASignatureFormat(
bytes memory _signature
) internal pure returns (bool) {
if (_signature.length != 65) {
return false;
}
uint8 v;
bytes32 r;
bytes32 s;
// Signature loading code
// we jump 32 (0x20) as the first slot of bytes contains the length
// we jump 65 (0x41) per signature
// for v we load 32 bytes ending with v (the first 31 come from s) then apply a mask
assembly {
r := mload(add(_signature, 0x20))
s := mload(add(_signature, 0x40))
v := and(mload(add(_signature, 0x41)), 0xff)
}
if (v != 27 && v != 28) {
return false;
}
// EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
// unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
// the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
// signatures from current libraries generate a unique signature with an s-value in the lower half order.
//
// If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
// with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
// vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
// these malleable signatures as well.
if (
uint256(s) >
0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0
) {
return false;
}
return true;
}
function extractECDSASignature(
bytes memory _fullSignature
) internal pure returns (bytes memory signature1, bytes memory signature2) {
require(_fullSignature.length == 130, "Invalid length");
signature1 = new bytes(65);
signature2 = new bytes(65);
// Copying the first signature. Note, that we need an offset of 0x20
// since it is where the length of the `_fullSignature` is stored
assembly {
let r := mload(add(_fullSignature, 0x20))
let s := mload(add(_fullSignature, 0x40))
let v := and(mload(add(_fullSignature, 0x41)), 0xff)
mstore(add(signature1, 0x20), r)
mstore(add(signature1, 0x40), s)
mstore8(add(signature1, 0x60), v)
}
// Copying the second signature.
assembly {
let r := mload(add(_fullSignature, 0x61))
let s := mload(add(_fullSignature, 0x81))
let v := and(mload(add(_fullSignature, 0x82)), 0xff)
mstore(add(signature2, 0x20), r)
mstore(add(signature2, 0x40), s)
mstore8(add(signature2, 0x60), v)
}
}
function payForTransaction(
bytes32,
bytes32,
Transaction calldata _transaction
) external payable override onlyBootloader {
bool success = _transaction.payToTheBootloader();
require(success, "Failed to pay the fee to the operator");
}
function prepareForPaymaster(
bytes32, // _txHash
bytes32, // _suggestedSignedHash
Transaction calldata _transaction
) external payable override onlyBootloader {
_transaction.processPaymasterInput();
}
fallback() external {
// fallback of default account shouldn't be called by bootloader under no circumstances
assert(msg.sender != BOOTLOADER_FORMAL_ADDRESS);
// If the contract is called directly, behave like an EOA
}
receive() external payable {
// If the contract is called directly, behave like an EOA.
// Note, that is okay if the bootloader sends funds with no calldata as it may be used for refunds/operator payments
}
}
DeployMultisig
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;
import "forge-std/Script.sol";
import "@era-contracts/libraries/SystemContractsCaller.sol";
import {Create2Factory} from "@era-contracts/Create2Factory.sol";
import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
import "../src/AAFactory.sol";
import "../src/TwoUserMultisig.sol";
contract DeployMultisig is Script {
function run() external {
uint256 deployerPrivateKey = vm.envUint("PRIVATE_KEY");
// Owners for the multisig account
// Can be random
address owner1 = vm.envAddress("OWNER_1");
address owner2 = vm.envAddress("OWNER_2");
// Read artifact file and get the bytecode hash
string memory artifact = vm.readFile(
"zkout/TwoUserMultisig.sol/TwoUserMultisig.json"
);
bytes32 multisigBytecodeHash = vm.parseJsonBytes32(artifact, ".hash");
console.log("Bytecode hash: ");
console.logBytes32(multisigBytecodeHash);
bytes32 salt = "1234";
vm.startBroadcast(deployerPrivateKey);
AAFactory factory = new AAFactory(multisigBytecodeHash);
console.log("Factory deployed at: ", address(factory));
// Mark the bytecode as a factory dependency
vmExt.zkUseFactoryDep("TwoUserMultisig");
factory.deployAccount(salt, owner1, owner2);
vm.stopBroadcast();
}
}
Running the script
forge script ./script/DeployMultisig.s.sol:DeployMultisig --rpc-url <RPC_URL> --private-key <PRIVATE_KEY> --broadcast --via-ir --zk-enable-eravm-extensions --zksync
For the complete source code, visit the minimal account abstraction multisig repository.