Contract Source Code:

// SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;

import "./MultiSigWalletProxy.sol";
import "./MultiSigWalletImplementation.sol";

contract MultiSigWalletFactory {

    event NewMultiSigWalletCreated(address wallet);

    function createMultiSigWallet(
        address _implementation,
        address[] memory owners,
        uint required,
        uint256 nonce
    ) public payable returns (address payable) {
        bytes32 salt = keccak256(abi.encodePacked(nonce, owners, required));
        bytes memory initCode = abi.encodePacked(
            type(MultiSigWalletProxy).creationCode,
            abi.encode(address(_implementation), abi.encodeWithSignature("initialize(address[],uint256)", owners, required))
        );

        address payable wallet;
        assembly {
            wallet := create2(0, add(initCode, 0x20), mload(initCode), salt)
            if iszero(extcodesize(wallet)) {
                revert(0, 0)
            }
        }

        emit NewMultiSigWalletCreated(wallet);

        return wallet;
    }
    
    function calculateMultiSigWalletAddress(
        address _implementation,
        address[] memory owners,
        uint required,
        uint256 nonce
    ) public view returns (address wallet) {
        bytes32 salt = keccak256(abi.encodePacked(nonce, owners, required));
        bytes memory initCode = abi.encodePacked(
            type(MultiSigWalletProxy).creationCode,
            abi.encode(address(_implementation), abi.encodeWithSignature("initialize(address[],uint256)", owners, required))
        );
        bytes32 hash = keccak256(abi.encodePacked(
            bytes1(0xff),
            address(this),
            salt,
            keccak256(initCode)
        ));

        return address(uint160(uint(hash)));
    }

    function createMultiSigWalletWithTransaction(
        address _implementation,
        address[] memory owners,
        uint required,
        uint256 nonce,
        MultiSigWalletImplementation.Transaction memory transaction,
        MultiSigWalletImplementation.Signature[] memory signatures
    ) public payable returns (address payable, bool) {
        address payable wallet = createMultiSigWallet(_implementation, owners, required, nonce);
        bool isOk = MultiSigWalletImplementation(wallet).batchSignature(transaction, signatures);
        return (wallet, isOk);
    }
}

// SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;

/// @title Multisignature wallet - Allows multiple parties to agree on transactions before execution.
/// @author Stefan George - <[email protected]>
contract MultiSigWalletImplementation {
    /*
     *  Events
     */
    event Confirmation(address indexed sender, uint indexed transactionId);
    event Revocation(address indexed sender, uint indexed transactionId);
    event Submission(uint indexed transactionId);
    event Execution(uint indexed transactionId);
    event ExecutionFailure(uint indexed transactionId);
    event Deposit(address indexed sender, uint value);
    event OwnerAddition(address indexed owner);
    event OwnerRemoval(address indexed owner);
    event RequirementChange(uint required);

    /*
     *  Constants
     */
    uint public constant MAX_OWNER_COUNT = 50;

    /*
     *  Storage
     */
    mapping(uint => Transaction) public transactions;
    mapping(uint => mapping(address => bool)) public confirmations;
    mapping(address => bool) public isOwner;
    mapping(bytes32 => bool) public txNonces;

    address[] public owners;
    uint public required;
    uint public transactionCount;

    bytes32 public DOMAIN_SEPARATOR;
    bytes32 constant EIP712DOMAIN_TYPEHASH = keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");
    bytes32 internal constant TRANSACTION_TYPEHASH = keccak256("Transaction(uint nonce,address destination,uint value,bytes data)");

    bool initialized;

    struct Transaction {
        uint nonce;
        address destination;
        uint value;
        bytes data;
        bool executed;
    }

    struct Signature {
        address signer;
        uint8 v;
        bytes32 r;
        bytes32 s;
    }

    /*
     *  Modifiers
     */
    modifier onlyWallet() {
        require(msg.sender == address(this));
        _;
    }

    modifier ownerDoesNotExist(address owner) {
        require(!isOwner[owner]);
        _;
    }

    modifier ownerExists(address owner) {
        require(isOwner[owner]);
        _;
    }

    modifier transactionExists(uint transactionId) {
        require(transactions[transactionId].destination != address(0));
        _;
    }

    modifier confirmed(uint transactionId, address owner) {
        require(confirmations[transactionId][owner]);
        _;
    }

    modifier notConfirmed(uint transactionId, address owner) {
        require(!confirmations[transactionId][owner]);
        _;
    }

    modifier notExecuted(uint transactionId) {
        require(!transactions[transactionId].executed);
        _;
    }

    modifier notNull(address _address) {
        require(_address != address(0));
        _;
    }

    modifier validRequirement(uint ownerCount, uint _required) {
        require(
            ownerCount <= MAX_OWNER_COUNT &&
                _required <= ownerCount &&
                _required != 0 &&
                ownerCount != 0
        );
        _;
    }

    /// @dev Receive function allows to deposit ether.
    receive() external payable {
        if (msg.value > 0) emit Deposit(msg.sender, msg.value);
    }

    /// @dev Fallback function allows to deposit ether.
    fallback() external payable {
        if (msg.value > 0) emit Deposit(msg.sender, msg.value);
    }

    /*
     * Public functions
     */
    /// @dev Contract constructor sets initial owners and required number of confirmations.
    constructor() {}

    function initialize(
        address[] memory _owners,
        uint _required
    ) validRequirement(_owners.length, _required) public {
        require(!initialized, "already initialized");

        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                EIP712DOMAIN_TYPEHASH,
                keccak256("MultiSigWallet"), // name
                keccak256("2"), // version
                block.chainid,
                address(this)
            )
        );

        for (uint i = 0; i < _owners.length; i++) {
            require(!isOwner[_owners[i]] && _owners[i] != address(0));
            isOwner[_owners[i]] = true;
        }
        owners = _owners;
        required = _required;

        initialized = true;
    }
    

    /// @dev Allows to add a new owner. Transaction has to be sent by wallet.
    /// @param owner Address of new owner.
    function addOwner(
        address owner
    )
        public
        onlyWallet
        ownerDoesNotExist(owner)
        notNull(owner)
        validRequirement(owners.length + 1, required)
    {
        isOwner[owner] = true;
        owners.push(owner);
        emit OwnerAddition(owner);
    }

    /// @dev Allows to remove an owner. Transaction has to be sent by wallet.
    /// @param owner Address of owner.
    function removeOwner(address owner) public onlyWallet ownerExists(owner) {
        isOwner[owner] = false;
        for (uint i = 0; i < owners.length - 1; i++)
            if (owners[i] == owner) {
                owners[i] = owners[owners.length - 1];
                delete owners[i];
                break;
            }
        if (required > owners.length) changeRequirement(owners.length);
        emit OwnerRemoval(owner);
    }

    /// @dev Allows to replace an owner with a new owner. Transaction has to be sent by wallet.
    /// @param owner Address of owner to be replaced.
    /// @param newOwner Address of new owner.
    function replaceOwner(
        address owner,
        address newOwner
    ) public onlyWallet ownerExists(owner) ownerDoesNotExist(newOwner) {
        for (uint i = 0; i < owners.length; i++)
            if (owners[i] == owner) {
                owners[i] = newOwner;
                break;
            }
        isOwner[owner] = false;
        isOwner[newOwner] = true;
        emit OwnerRemoval(owner);
        emit OwnerAddition(newOwner);
    }

    /// @dev Allows to change the number of required confirmations. Transaction has to be sent by wallet.
    /// @param _required Number of required confirmations.
    function changeRequirement(
        uint _required
    ) public onlyWallet validRequirement(owners.length, _required) {
        required = _required;
        emit RequirementChange(_required);
    }

    /// @dev Allows an owner to submit and confirm a transaction.
    /// @param destination Transaction target address.
    /// @param value Transaction ether value.
    /// @param data Transaction data payload.
    /// @return transactionId Returns transaction ID.
    function submitTransaction(
        address destination,
        uint value,
        bytes memory data
    ) public returns (uint transactionId) {
        transactionId = addTransaction(destination, value, data);
        confirmTransaction(transactionId);
    }

    /// @dev Allows an owner to confirm a transaction.
    /// @param transactionId Transaction ID.
    function confirmTransaction(
        uint transactionId
    )
        public
        ownerExists(msg.sender)
        transactionExists(transactionId)
        notConfirmed(transactionId, msg.sender)
    {
        confirmations[transactionId][msg.sender] = true;
        emit Confirmation(msg.sender, transactionId);
        executeTransaction(transactionId);
    }

    /// @dev Allows an owner to revoke a confirmation for a transaction.
    /// @param transactionId Transaction ID.
    function revokeConfirmation(
        uint transactionId
    )
        public
        ownerExists(msg.sender)
        confirmed(transactionId, msg.sender)
        notExecuted(transactionId)
    {
        confirmations[transactionId][msg.sender] = false;
        emit Revocation(msg.sender, transactionId);
    }

    /// @dev Allows anyone to execute a confirmed transaction.
    /// @param transactionId Transaction ID.
    function executeTransaction(
        uint transactionId
    )
        public
        ownerExists(msg.sender)
        confirmed(transactionId, msg.sender)
        notExecuted(transactionId)
    {
        _executeTransaction(transactionId);
    }

    function _executeTransaction(
        uint transactionId
    ) internal notExecuted(transactionId) {
        if (isConfirmed(transactionId)) {
            Transaction storage txn = transactions[transactionId];
            txn.executed = true;
            if (
                external_call(
                    txn.destination,
                    txn.value,
                    txn.data.length,
                    txn.data
                )
            ) emit Execution(transactionId);
            else {
                emit ExecutionFailure(transactionId);
                txn.executed = false;
            }
        }
    }

    // call has been separated into its own function in order to take advantage
    // of the Solidity's code generator to produce a loop that copies tx.data into memory.
    function external_call(
        address destination,
        uint value,
        uint dataLength,
        bytes memory data
    ) internal returns (bool) {
        bool result;
        assembly {
            let x := mload(0x40) // "Allocate" memory for output (0x40 is where "free memory" pointer is stored by convention)
            let d := add(data, 32) // First 32 bytes are the padded length of data, so exclude that
            result := call(
                sub(gas(), 34710), // 34710 is the value that solidity is currently emitting
                // It includes callGas (700) + callVeryLow (3, to pay for SUB) + callValueTransferGas (9000) +
                // callNewAccountGas (25000, in case the destination address does not exist and needs creating)
                destination,
                value,
                d,
                dataLength, // Size of the input (in bytes) - this is what fixes the padding problem
                x,
                0 // Output is ignored, therefore the output size is zero
            )
        }
        return result;
    }

    /// @dev Returns the confirmation status of a transaction.
    /// @param transactionId Transaction ID.
    /// @return status Confirmation status.
    function isConfirmed(uint transactionId) public view returns (bool status) {
        uint count = 0;
        for (uint i = 0; i < owners.length; i++) {
            if (confirmations[transactionId][owners[i]]) count += 1;
            if (count == required) return true;
        }
    }

    /*
     * Internal functions
     */
    /// @dev Adds a new transaction to the transaction mapping, if transaction does not exist yet.
    /// @param destination Transaction target address.
    /// @param value Transaction ether value.
    /// @param data Transaction data payload.
    /// @return transactionId Returns transaction ID.
    function addTransaction(
        address destination,
        uint value,
        bytes memory data
    ) internal notNull(destination) returns (uint transactionId) {
        if(transactions[transactionId].destination == address(0)) {
            transactionId = transactionCount;
            transactions[transactionId] = Transaction({
                nonce: transactionId,
                destination: destination,
                value: value,
                data: data,
                executed: false
            });
            transactionCount += 1;
            
            emit Submission(transactionId);
        } else {
            revert("transactionId already exist");
        }
    }

    /*
     * Web3 call functions
     */
    /// @dev Returns number of confirmations of a transaction.
    /// @param transactionId Transaction ID.
    /// @return count Number of confirmations.
    function getConfirmationCount(
        uint transactionId
    ) public view returns (uint count) {
        for (uint i = 0; i < owners.length; i++)
            if (confirmations[transactionId][owners[i]]) count += 1;
    }

    /// @dev Returns total number of transactions after filers are applied.
    /// @param pending Include pending transactions.
    /// @param executed Include executed transactions.
    /// @return count Total number of transactions after filters are applied.
    function getTransactionCount(
        bool pending,
        bool executed
    ) public view returns (uint count) {
        for (uint i = 0; i < transactionCount; i++)
            if (
                (pending && !transactions[i].executed) ||
                (executed && transactions[i].executed)
            ) count += 1;
    }

    /// @dev Returns list of owners.
    /// @return List of owner addresses.
    function getOwners() public view returns (address[] memory) {
        return owners;
    }

    /// @dev Returns array with owner addresses, which confirmed transaction.
    /// @param transactionId Transaction ID.
    /// @return _confirmations Returns array of owner addresses.
    function getConfirmations(
        uint transactionId
    ) public view returns (address[] memory _confirmations) {
        address[] memory confirmationsTemp = new address[](owners.length);
        uint count = 0;
        uint i;
        for (i = 0; i < owners.length; i++)
            if (confirmations[transactionId][owners[i]]) {
                confirmationsTemp[count] = owners[i];
                count += 1;
            }
        _confirmations = new address[](count);
        for (i = 0; i < count; i++) _confirmations[i] = confirmationsTemp[i];
    }

    /// @dev Returns list of transaction IDs in defined range.
    /// @param from Index start position of transaction array.
    /// @param to Index end position of transaction array.
    /// @param pending Include pending transactions.
    /// @param executed Include executed transactions.
    /// @return _transactionIds Returns array of transaction IDs.
    function getTransactionIds(
        uint from,
        uint to,
        bool pending,
        bool executed
    ) public view returns (uint[] memory _transactionIds) {
        uint[] memory transactionIdsTemp = new uint[](transactionCount);
        uint count = 0;
        uint i;
        for (i = 0; i < transactionCount; i++)
            if (
                (pending && !transactions[i].executed) ||
                (executed && transactions[i].executed)
            ) {
                transactionIdsTemp[count] = i;
                count += 1;
            }
        _transactionIds = new uint[](to - from);
        for (i = from; i < to; i++)
            _transactionIds[i - from] = transactionIdsTemp[i];
    }

    function hashTransaction(
        Transaction memory transaction
    ) public pure returns (bytes32) {
        return
            keccak256(
                abi.encode(
                    TRANSACTION_TYPEHASH,
                    transaction.nonce,
                    transaction.destination,
                    transaction.value,
                    keccak256(bytes(transaction.data))
                )
            );
    }

    function getTransactionMessage(
        Transaction memory transaction
    ) public view returns (bytes32) {
        bytes32 digest = keccak256(
            abi.encodePacked(
                "\x19\x01",
                DOMAIN_SEPARATOR,
                hashTransaction(transaction)
            )
        );
        return digest;
    }

    function batchSignature(Transaction memory txn, Signature[] memory sortedSignatures) public returns (bool isOK) {
        require(sortedSignatures.length >= required, "invalid signature data length");

        bytes32 digest = keccak256(
            abi.encodePacked(
                "\x19\x01",
                DOMAIN_SEPARATOR,
                hashTransaction(txn)
            )
        );
        require(!txNonces[digest], "tx-executed");

        uint256 txId = txn.nonce;
        address lastOwner = address(0);
        for(uint i = 0; i < sortedSignatures.length; i++) {
            Signature memory signature = sortedSignatures[i];
            address signer = signature.signer;
            uint8 v = signature.v;
            bytes32 r = signature.r;
            bytes32 s = signature.s;

            address currentOwner = ecrecover(digest, v, r, s);

            // to save gas, must need signature.signer sorted
            require(currentOwner > lastOwner && isOwner[currentOwner] && signer == currentOwner, "error-sig");
            lastOwner = currentOwner;
            emit Confirmation(signer, txId);
        }

        txn.executed = true;
        txNonces[digest] = true;
        if (external_call(txn.destination, txn.value, txn.data.length, txn.data)) {
            emit Execution(txId);
        } else {
            emit ExecutionFailure(txId);
            txn.executed = false;
        }

        return txn.executed;
    }

    struct Call {
        address target;
        uint value;
        bytes data;
    }

    function multiCall(
        Call[] memory calls
    ) public onlyWallet {
        for (uint i = 0; i < calls.length; i++) {
            if (external_call(
                calls[i].target,
                calls[i].value,
                calls[i].data.length,
                calls[i].data
            )) {}
            else {
                revert("internal call failed");
            }
        }
    }
}

// SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;

import "./MultiSigWalletImplementation.sol";


contract MultiSigWalletImplementationBeacon {

    event MultiSigWalletImplementationDeployed(address indexed implementation);

    constructor() {
        MultiSigWalletImplementation implementation = new MultiSigWalletImplementation();

        address[] memory owners = new address[](1);
        owners[0] = msg.sender;

        implementation.initialize(owners, 1);
        
        emit MultiSigWalletImplementationDeployed(address(implementation));
    }
}

// SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;

contract MultiSigWalletProxy {
    address public implementation;

    constructor(address _implementation, bytes memory _data) {
        implementation = _implementation;
        if(_data.length > 0) {
            (bool success,) = _implementation.delegatecall(_data);
            require(success, "MultiSigWalletProxy: Initialization failed");
        }
    }

    fallback() external payable {
        _delegate(implementation);
    }

    receive() external payable {
        _delegate(implementation);
    }

    function _delegate(address _implementation) internal {
        assembly {
            calldatacopy(0, 0, calldatasize())
            let result := delegatecall(gas(), _implementation, 0, calldatasize(), 0, 0)
            returndatacopy(0, 0, returndatasize())
            switch result
            case 0 { 
                revert(0, returndatasize()) 
            } default { 
                return(0, returndatasize())
            }
        }
    }
}