Cosmos ZK Voting

A secure and anonymous governance voting system leveraging Zero-Knowledge (ZK) proofs on the Cosmos blockchain.

Overview

Cosmos ZK Voting is a governance voting system designed to ensure voter anonymity while maintaining the integrity and security of the voting process. Utilizing Zero-Knowledge proofs, this system allows voters to participate in governance without revealing their identities, fostering a more private and secure voting environment.

Features

• Anonymous Voting: Protects voter identities using Zero-Knowledge proofs.
• Decentralized: Built on the Cosmos blockchain for enhanced security and scalability.
• Secure Key Management: Ensures the safety of prover and verifier keys.
• dispatcher Support: Facilitates seamless vote transactions through a dedicated dispatcher service.
• Flexible Proposal Management: Create and manage governance proposals with ease.

Getting Started

Follow the steps below to set up and run Cosmos ZK Voting locally.

Prerequisites

• Go (version 1.18 or higher)
• Cosmos SDK installed
• Git

Clone the Repository

git clone https://github.com/vitwit/cosmos-zk-gov

git fetch

git checkout main

Install zkappd Binary

Build and install the zkappd binary required to run the Cosmos ZK Voting chain.

make install

Run Local Testnet

Initialize and start a local testnet.

1. Initialize and Start the Chain:
   Modify the scripts/init-zkgovapp.sh script according to your requirements.
   make init-zkgovapp will the run chain.

make init-zkgovapp

ZK Prover and Verifier Keys

Before setting up the chain, generate the ZK prover and verifier keys.

Create Keys Directory:

mkdir keys

1. Generate ZK Keys:

make generate-zk-keys

2. This command runs the groth16.setup() function defined in /x/zkgov/client/zk/main.go.
   Note: Multiple prover and verifier key pairs are generated (e.g., verifier-2, verifier-3, verifier-4, etc.) to accommodate varying Merkle proof sizes. Use the appropriate key pair dynamically as needed.

Future Enhancements

• Optimize Merkle Implementation: Aim for a constant Merkle tree size of 2^31 and improve update operations from O(n) to O(log n).

Dispatcher

The Dispatcher is an HTTP server that listens for vote transactions, signs them with a valid chain address, and broadcasts them on-chain.

Why Use a Dispatcher?

Vote transactions must be sent from a different, unlinkable address than the registered address. Since most users may not have multiple unlinkable addresses, the dispatcher serves as an intermediary to handle this securely.

Security Assurance: The Dispatcher cannot manipulate transactions because the ZK proof guarantees transaction validity without exposing user secrets.

Running the Dispatcher

1.Start the dispatcher:

zkappd  tx zk-gov run-dispatcher --from {key} --keyring-backend test --chain-id {chain-id} -y

Alternatively, you can run a predefined dispatcher (e.g., alice):

make run-alice-dispatcher

2. This command starts an HTTP server on port 8080 by default. You can change the port using the --dispatcherPort {port} flag.

Transactions

Create a Proposal

Create a new governance proposal that can be voted on with a YES or NO.

Note: This implementation is basic and intended for testing. A more robust system is recommended for production use.

Proposal ID: Starts at 1 and increments sequentially.

zkappd  tx zk-gov create-proposal [proposal-title] [proposal-description] --from [address] --keyring-backend test --chain-id [chain-id]

Or use a make command for convenience:

make create-proposal-a

Create Commitments Directory:

mkdir commitments

Register a Vote

Register a vote commitment, which will be used later to anonymize the actual vote.

zkappd  tx zk-gov register-vote [proposal-id] {"YES"/"NO"} --from [actual-voter-address] --keyring-backend test --chain-id [chain-id]

Alternatively, use predefined make commands:

make register-alice-vote

make register-bob-vote

make register-charlie-vote

make register-david-vote

Cast a Vote

After registering a vote commitment, generate a ZK proof to cast the actual vote. This proof verifies that you know the valid commitment without revealing your identity.

Important: The vote transaction must be signed by a different, unlinkable address from the one used to register the vote commitment. Use the dispatcher to facilitate this process.

Without dispatcher

zkappd  tx zk-gov vote [proposal-id] [register-vote-address] --from [different-unlinkable-address] --keyring-backend test --chain-id [chain-id]

Or use make commands:

make broadcast-alice-vote
make broadcast-bob-vote

With Dispatcher

zkappd  tx zk-gov vote [proposal-id] [register-vote-address] --dispatcher [dispatcher-address]

Or use make commands:

make broadcast-charlie-vote-via-dispatcher

make broadcast-david-vote-via-dispatcher

Query a Proposal

View the state of a proposal, including commitments and votes.

zkappd  q zk-gov get-proposal-info [proposal-id]

Contributing

Contributions are welcome! Please fork the repository and submit a pull request for any enhancements or bug fixes.

License

This project is licensed under the MIT License.

Contact

For questions or support, please open an issue on the GitHub repository or reach out to [email protected].