Lighthouse

Lighthouse is an anonymous, private, and self-tallying e-voting protocol. The current implementation is based on the Ethereum blockchain, with inspirations from Semaphore when it comes to zk proofs.

Installation

The installation phase is only needed if you want to start experimenting with the PoC.

Platform

You can run the PoC on both Linux and Windows via WSL. Running this on pure windows is not tested, but as long as the dependencies are successfully installed, you should be fine.

Installing dependencies

Node: The implementation should work with Node v14+; the actual version used during development was v14.17.10. For optimal node installation experience, I suggest using nvm. Check that your node installation is successful before proceeding to next step:

node --version

which should print out the version.

npx: Install Nodejs package runner via:

npm install -g npx

Solidity Compiler: The compile_sol.sh script provides you with appropriate solc version needed for the project. However, you can install solc via tools like svm or Solidity binary packages manually.

Lerna: I use lerna for managing dependencies for multiple packages. Install lerna using

npm install lerna -g

Libraries: Once the previous steps are done, install project libraries via

git clone https://github.com/creepteks/lighthouse.git && cd lighthouse
lerna bootstrap

This command installs the dependencies for separate packages inside the lighthouse project.

PoC: Simple e-voting scenario

To start a test voting scenario, you have to follow 4 steps:

01: Trusted Setup

The current protocol needs trusted setup in order to function. A non-secure, development-only trusted setup can be preformed by fast_build_circuits.sh. For more info on how to do a trusted setup as MPC, refer to snarkjs, since the current protocol uses snarkjs for zkSNARKs proofs and verifications.

cd circuits
./scripts/fast_build_circuits.sh
cd ..

02: Using a test blockchain

While you can use any Ethereum Testnets, we can simply use ganache to test the scenario. Fire up an instance of ganache using the following commands:

cd ethcode
./scripts/start_ganache.sh

03: Compiling E-voting smart contract

We also need to compile the voting smart contract and its dependencies:

cd ethcode
./scripts/compile_sol.sh

This will download solc if necessary, and then compile the smart contracts.

04: Starting the scenario

Now, everything should be ready for testing. The Scenario includes

• Initialization phase
  • creating the voting key pair
  • deploying contracts to blockchain
• Registration
  • creating voter's key pair
  • registering via smart contract
• Voting
  • creating zk-proof of being registered
  • voting anonymously via smart contract
• Tallying
  • decrypting every vote stored on the smart contract with voting secret key
  • counting the votes

In order to start this scenario, run the following commands:

cd ethcode
node ./scripts/voting_scenario.js

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

GPL-3.0