ZeroKnowledgeVoting

Introduction

ZeroKnowledgeVoting is a demo application showcasing a zero-knowledge voting system using zk-SNARKs. It allows voters to cast votes anonymously while ensuring the integrity of the voting process. Results are displayed in real-time. This project leverages zkVerify's public, permissionless ZK-proof verification blockchain to enhance trust and transparency.

Hackathon Alignment

This project aligns with the zkVerify Hackathon’s objectives by:

• Leveraging zkVerify: It uses zkVerify’s Groth16 verifier on the BN-254 curve to validate zero-knowledge proofs.
• Promoting Decentralization: Demonstrates a real-world use case of decentralized proof verification for secure and anonymous voting.
• Innovative Application: Showcases how ZKPs can enhance trust, privacy, and transparency in democratic processes.

Setup Instructions

Prerequisites

• Ensure Node.js is installed. The demo has been tested with Node.js v23.3.0.
• You need wallets funded with:
  • ACME tokens for zkVerify operations.
  • Sepolia ETH for Ethereum transactions.

Instructions

1. Clone the repository:

   git clone [email protected]:zkPikachu/ZeroKnowledgeVoting.git

2. Navigate to the project directory:

   cd ZeroKnowledgeVoting

3. Move to the contractsfolder:

  cd contracts

4. Set up environment variables:

   • Create a .env file using env.template as an example:

     cp env.template .env

5. Navigate to the src folder and find the zkVote.sol smart contract. This contains the Solidity code for your voting Smart Contract.

6. Visit Remix Ethereum IDE and ensure your wallet is connected to the Sepolia Testnet.

7. Copy zkVote.sol code and paste it into a new file in Remix.

8. Set Constructor Parameters:

• In zkVote.sol, the constructor requires:
  • _zkvContract: The address of the zkVerify contract.
  • _vkHash: The verification key hash for your circuit.
• These parameters are stored in your .env file in your project folder contracts.

9. Deploy the Contract to Sepolia and copy the deployed contract address. Ensure the Ethereum address used to deploy the contract is the one you’re using for the app (ETH_SECRET_KEY should be the private key for that address).

10. Paste the contract address into the .env.template file in your app folder as ETH_APP_CONTRACT_ADDRESS

11. Move to the app folder:

cd ../../app

12. Set up environment variables:

• Create a .env file using env.template as an example:

  cp env.template .env

• Create a .env.secrets file using env.secrets.template as an example:

  cp env.secrets.template .env.secrets

  • In .env.secrets:
    • ZKV_SEED_PHRASE: The seed phrase of a wallet with sufficient ACME tokens.
    • ETH_SECRET_KEY: The secret key of an Ethereum wallet with sufficient Sepolia ETH.

13. Install dependencies:

npm install

14. Initialize the voting poll:

npm run init-poll

• This command registers voters from voterRegistry.json and generates the voterMapping.json file. You can vote using one of the account addresses listed in voterRegistry.json.

15. Start the application:

npm start

16. Open the application in your browser:

• To cast a vote, go to: http://localhost:3000
• To view voting results, go to: http://localhost:3001

This process submits a transaction to the App Contract, including the necessary attestation details obtained from ZKVerify (such as the attestation ID and Merkle path). Upon successful submission and validation, the App Contract confirms and acknowledges that your vote has been casted.

Usage

• Voting: Enter your account address (from voterRegistry.json) and choose a candidate to cast your vote.
• Results: View the real-time voting results on the results page.

Example .env and .env.secrets

.env

ZKV_RPC_URL="wss://testnet-rpc.zkverify.io"
ETH_RPC_URL="https://ethereum-sepolia-rpc.publicnode.com"

ETH_ZKVERIFY_CONTRACT_ADDRESS=0x209f82A06172a8d96CF2c95aD8c42316E80695c1
ETH_APP_CONTRACT_ADDRESS=0x2719FB1f292C434305cefe52d82e2A53CecDcF85

.env.secrets

ZKV_SEED_PHRASE="your wallet seed phrase with ACME tokens"
ETH_SECRET_KEY=your ethereum wallet private key starting with 0x

Notes

• Ensure your wallets are sufficiently funded before running the application.
• For more information, refer to the source code or contact the repository owner.

Technical Architecture

1. App:

   • The Node.js backend handles proof generation, verification, and interaction with the blockchain.
   • Provides APIs for vote submission and results display.

2. Frontend:

   • Web-based UI built using HTML and JavaScript for casting votes and viewing results.

3. zk-SNARK Circuit:

   • Written in circom, the circuit enforces rules such as verifying Merkle paths, vote commitments, and nullifiers.
   • Uses groth16 as the proving system.

4. zkVote Smart Contract:

   • A Solidity contract deployed on the Ethereum blockchain.
   • Integrates with the zkVerify platform for off-chain proof verification and ensures rules like no double voting.

License

This project is licensed under the MIT License.