pragma solidity ^0.7.6;
contract TornadoCashMultiSigWallet {
event Deposit(address indexed sender, uint amount, uint balance);
event SubmitTransaction(
address indexed owner,
uint indexed txIndex,
address indexed to,
uint value,
bytes data
);
event ConfirmTransaction(address indexed owner, uint indexed txIndex);
event RevokeConfirmation(address indexed owner, uint indexed txIndex);
event ExecuteTransaction(address indexed owner, uint indexed txIndex);
address[] public owners;
mapping(address => bool) public isOwner;
uint public numConfirmationsRequired;
struct Transaction {
address to;
uint value;
bytes data;
bool executed;
uint numConfirmations;
}
// mapping from tx index => owner => bool
mapping(uint => mapping(address => bool)) public isConfirmed;
Transaction[] public transactions;
modifier onlyOwner() {
require(isOwner[msg.sender], "not owner");
_;
}
modifier txExists(uint _txIndex) {
require(_txIndex < transactions.length, "tx does not exist");
_;
}
modifier notExecuted(uint _txIndex) {
require(!transactions[_txIndex].executed, "tx already executed");
_;
}
modifier notConfirmed(uint _txIndex) {
require(!isConfirmed[_txIndex][msg.sender], "tx already confirmed");
_;
}
constructor(address[] memory _owners, uint _numConfirmationsRequired) {
require(_owners.length > 0, "owners required");
require(
_numConfirmationsRequired > 0 && _numConfirmationsRequired <= _owners.length,
"invalid number of required confirmations"
);
for (uint i = 0; i < _owners.length; i++) {
address owner = _owners[i];
require(owner != address(0), "invalid owner");
require(!isOwner[owner], "owner not unique");
isOwner[owner] = true;
owners.push(owner);
}
numConfirmationsRequired = _numConfirmationsRequired;
}
receive() payable external {
emit Deposit(msg.sender, msg.value, address(this).balance);
}
function submitTransaction(address _to, uint _value, bytes memory _data)
public
onlyOwner
{
uint txIndex = transactions.length;
transactions.push(Transaction({
to: _to,
value: _value,
data: _data,
executed: false,
numConfirmations: 0
}));
emit SubmitTransaction(msg.sender, txIndex, _to, _value, _data);
}
function confirmTransaction(uint _txIndex)
public
onlyOwner
txExists(_txIndex)
notExecuted(_txIndex)
notConfirmed(_txIndex)
{
Transaction storage transaction = transactions[_txIndex];
transaction.numConfirmations += 1;
isConfirmed[_txIndex][msg.sender] = true;
emit ConfirmTransaction(msg.sender, _txIndex);
}
function executeTransaction(uint _txIndex)
public
onlyOwner
txExists(_txIndex)
notExecuted(_txIndex)
{
Transaction storage transaction = transactions[_txIndex];
require(
transaction.numConfirmations >= numConfirmationsRequired,
"cannot execute tx"
);
transaction.executed = true;
(bool success, ) = transaction.to.call{value: transaction.value}(transaction.data);
require(success, "tx failed");
emit ExecuteTransaction(msg.sender, _txIndex);
}
function revokeConfirmation(uint _txIndex)
public
onlyOwner
txExists(_txIndex)
notExecuted(_txIndex)
{
Transaction storage transaction = transactions[_txIndex];
require(isConfirmed[_txIndex][msg.sender], "tx not confirmed");
transaction.numConfirmations -= 1;
isConfirmed[_txIndex][msg.sender] = false;
emit RevokeConfirmation(msg.sender, _txIndex);
}
function getOwners() public view returns (address[] memory) {
return owners;
}
function getTransactionCount() public view returns (uint) {
return transactions.length;
}
function getTransaction(uint _txIndex)
public
view
returns (address to, uint value, bytes memory data, bool executed, uint numConfirmations)
{
Transaction storage transaction = transactions[_txIndex];
return (
transaction.to,
transaction.value,
transaction.data,
transaction.executed,
transaction.numConfirmations
);
}
}
This the part of code which would be added to the formal proposal in the future once the community has made his mind, with a few options. Basically a multi sig is a wallet which can execute txs only at the condition that some of the signers approve it (e.g. 3 out of 5).
