@aduh95/caritat

Caritat

The name comes from Marie Jean Antoine Nicolas de Caritat, Marquis of Condorcet, French philosopher and mathematician, notably known for championing an election method that now named after him.

The goal of this project is to allow organisations of people working remotely to cast votes is a secure and transparent way, using a git repository collect and authenticate votes.

Usage

Participate to a vote using Caritat

Node.js CLI

Requires Node.js 16+ and git.

If the vote is setup on a GitHub pull request and you have gh locally installed and logged in to your GitHub account:

npx --package=@aduh95/caritat voteOnGitHub <pr-url>

Otherwise, you can specify the details manually:

npx --package=@aduh95/caritat voteUsingGit \
  --repo=<repo-url> --branch=<branch-name> \
  --path=<subfolder-where-the-vote-data-is-stored> \
  --handle=<your-github-handle>

Shell scripts

You can use one of the shell script from the sh/ folder. Requires openssl (LibreSSL CLI is not compatible) and git to be available on the local machine.

On a Unix-like OS:

sh/voteUsingGit.sh <your-github-handle> <repo-url> <branch-name> <subfolder-where-the-vote-data-is-stored>

On Windows:

sh/voteUsingGit.ps1 <your-github-handle> <repo-url> <branch-name> <subfolder-where-the-vote-data-is-stored>

Web UI

Only works for vote that are hosted on a GitHub pull request.

Visit https://stduhpf.github.io/caritat/, paste the URL of the pull request, and create the JSON file containing your encrypted ballot using GitHub web UI.

Setup a vote using Caritat

Node.js script

npx --package=@aduh95/caritat generateNewVoteFolder \
 --repo "<repo-url>" --branch "<new-vote-branch-name>" \
 --directory "<relative-path-to-new-vote-folder>" \
 --subject "Vote subject" \
 --candidate "Candidate 1" --candidate "etc." \
 --allowed-voter "[e-mail]" --allowed-voter "[e-mail]" \
 --shareholder "[e-mail]" --shareholder "[e-mail]" \
 --shareholders-threshold 2

Shell script / git-less setup

Requires openssl (LibreSSL CLI is not compatible), gpg, and node. Use the sh/generateNewVoteFolder.sh script.

sh/generateNewVoteFolder.sh <path-to-dir>

This will generate three files that will be used to let participants vote. You can then commit those files and push this to a new branch (optionally open the vote pull request). If you are participating to that vote yourself, you should cast your vote right away using one of the methods described above.

FAQ

Who do I need to trust?

• As a voter, you need to trust the instigator for:
  • using a reliable hardware and software to generate the private key and encrypt it, and to not store it anywhere.
  • not leaking the private key before the vote closes if they have kept the private key (which they should not do).
  • not basing their vote in function of what other has voted (having the instigator always vote first helps alleviate this issue).
• As a voter, you need to trust the panel of secret holders for:
  • not reconstitue the private key before the vote closes.
  • not leaking the private key before the vote closes (if they have reconstructed the private key, which they should not do).
  • not basing their vote in function of what other has voted (if they have reconstructed the private key, which they should not do).
• As a voter or the instigator, you need to trust the git commits are genuine. Enforcing the use of PGP signatures on vote commits can help with that.

Can a participant tamper with the votes?

When using git, a participant could force push the branch and remove or modify ballots from other participants. Adding protection on the branch on which the vote is happening can help prevent this.

When voting using this tool, are my choices public?

Ballots are encrypted using a public key generated for the vote, only someone in possession for the private key is theoretically able to decipher the ballot. Typically, no one should be in possession of the full private key (although there is no way of ensuring that, see "Who do I need to trust?" section) until the vote closes. Unless the vote needs to stay private, a recommended practice is to publish the vote private key, effectively making everyone's choices public.

Making the non-encrypted ballot available publicly is a great way to ensure the election was not rigged. Everyone can check that the ballot counted as their has not been altered and that the result adds up. It's still possible to not make them public (to keep the vote anonymous), but that requires to trust a single authority (the vote instigator).

Why are the ballots encrypted?

Encrypting the ballot is necessary to ensure people voting early do not interfere or influence folks voting after them. At the end of the vote, the instigator of the vote can share the private key, so anyone can decrypt the ballots and verify the result themself. Or the voters can decide that the private key won't be shared in order to keep the votes anonymous (the instigator of the vote needs to be able the votes to do the counting, they have to be trusted).

How are the votes authenticated?

Voters can sign their commit using PGP. When doing the counting, the system uses the git commit metadata to attribute a ballot to a voter. If a voter casts several ballots, the system only counts the most recent one.

What happens if the vote instigator lose access to the decrypting key?

The vote ballots cannot be deciphered, the process needs to start again (unless you have a quantum computer at home).

Could this tool used for any elections?

The license makes no restrictions on how this tool should be used, but keep in mind that, as any electronic voting system, it can only be trusted as long as the unanonymized vote ballots are made public as soon as the vote closed, which may or may not be OK depending on the type of election you are using this for.