Multi-Sig Smart Contract

MultiSig.sol

vim: set ft=solidity:
pragma solidity ^0.4.24;

contract MultiSig {
    
    struct Proposal {
        address to;
        uint amount;
        mapping(address => bool) signers;
        bool finalized;
    }
    
    address[] public signers;
    mapping(address => bool) canSign;
    Proposal[] public proposals;
    
    
    constructor(address[] initSigners) public {
        signers = initSigners;
        for(uint i = 0; i < signers.length; i++) {
            canSign[signers[i]] = true;
        }
    }
    
    function () payable public {
        // allow this contract to receive eth
    }
    
    modifier isSigner(address potentialSigner ) {
        require(canSign[potentialSigner]);
        _;
    }
    
    function proposeSend(address to, uint value) public isSigner(msg.sender) {
        proposals.push(Proposal({
            to: to,
            amount: value,
            finalized: false
        }));
    }
    
    function sign(uint proposalIndex) public isSigner(msg.sender) {
        proposals[proposalIndex].signers[msg.sender] = true;
    }
    
    function checkAllSigned(uint proposalIndex) public view returns(bool) {
        bool allSigned = true;
        for(uint i = 0; i < signers.length; i++) {
            if(proposals[proposalIndex].signers[signers[i]] == false) {
                allSigned = false;
            }
        }
        return allSigned;
    }
    
    modifier allSigned(uint proposalIndex) {
        require(checkAllSigned(proposalIndex));
        _;
    }
    
    function finalize(uint proposalIndex) allSigned(proposalIndex) public isSigner(msg.sender) {
        proposals[proposalIndex].finalized = true;
        proposals[proposalIndex].to.transfer(proposals[proposalIndex].amount);
    }
    
}