Election Voting Smart Contract

We found a tutorial to follow for this one that gave us code to test out between the three of us: https://karl.tech/learning-solidity-part-2-voting/

With this we were able to hash a choice "1" or "2" and cast our votes with a unique password within the solidity remix compiler. Submitting the vote opens up our metamask client that contains access to our rinkeby test network account. To officially submit a vote we send a transaction into the blockchain with our encrypted vote. Once the vote is mined it will be submitted to the contract and it will track votes for each choice. Add more about this project so we can track our progress.

`pragma solidity ^0.4.7;

contract CommitRevealElection { // The two choices for your vote string public choice1; string public choice2;

// Information about the current status of the vote
uint public votesForChoice1;
uint public votesForChoice2;
uint public commitPhaseEndTime;
uint public numberOfVotesCast = 0;

// The actual votes and vote commits
bytes32[] public voteCommits;
mapping(bytes32 => string) voteStatuses; // Either `Committed` or `Revealed`

// Events used to log what's going on in the contract
event logString(string);
event newVoteCommit(string, bytes32);
event voteWinner(string, string);

// Constructor used to set parameters for the this specific vote
function CommitRevealElection(uint _commitPhaseLengthInSeconds, 
                              string _choice1, 
                              string _choice2) {
    if (_commitPhaseLengthInSeconds < 20) {
        throw;
    }
    commitPhaseEndTime = now + _commitPhaseLengthInSeconds * 1 seconds;
    choice1 = _choice1;
    choice2 = _choice2;
}

function commitVote(bytes32 _voteCommit) {
    if (now > commitPhaseEndTime) throw; // Only allow commits during committing period

    // Check if this commit has been used before
    bytes memory bytesVoteCommit = bytes(voteStatuses[_voteCommit]);
    if (bytesVoteCommit.length != 0) throw;

    // We are still in the committing period & the commit is new so add it
    voteCommits.push(_voteCommit);
    voteStatuses[_voteCommit] = "Committed";
    numberOfVotesCast ++;
    newVoteCommit("Vote committed with the following hash:", _voteCommit);
}

function revealVote(string _vote, bytes32 _voteCommit) {
    if (now < commitPhaseEndTime) throw; // Only reveal votes after committing period is over

    // FIRST: Verify the vote & commit is valid
    bytes memory bytesVoteStatus = bytes(voteStatuses[_voteCommit]);
    if (bytesVoteStatus.length == 0) {
        logString('A vote with this voteCommit was not cast');
    } else if (bytesVoteStatus[0] != 'C') {
        logString('This vote was already cast');
        return;
    }

    if (_voteCommit != keccak256(_vote)) {
        logString('Vote hash does not match vote commit');
        return;
    }

    // NEXT: Count the vote!
    bytes memory bytesVote = bytes(_vote);
    if (bytesVote[0] == '1') {
        votesForChoice1 = votesForChoice1 + 1;
        logString('Vote for choice 1 counted.');
    } else if (bytesVote[0] == '2') {
        votesForChoice2 = votesForChoice2 + 1;
        logString('Vote for choice 2 counted.');
    } else {
        logString('Vote could not be read! Votes must start with the ASCII character `1` or `2`');
    }
    voteStatuses[_voteCommit] = "Revealed";
}

function getWinner () constant returns(string) {
    // Only get winner after all vote commits are in
    if (now < commitPhaseEndTime) throw;
    // Make sure all the votes have been counted
    if (votesForChoice1 + votesForChoice2 != voteCommits.length) throw;

    if (votesForChoice1 > votesForChoice2) {
        voteWinner("And the winner of the vote is:", choice1);
        return choice1;
    } else if (votesForChoice2 > votesForChoice1) {
        voteWinner("And the winner of the vote is:", choice2);
        return choice2;
    } else if (votesForChoice1 == votesForChoice2) {
        voteWinner("The vote ended in a tie!", "");
        return "It was a tie!";
    }
}

cyberdefendersprogram / Pensieve

Election Voting Smart Contract #4