alexroan / governorzk

GovernorZK - Anonymized OnChain Governance

GovernorZK is a ZK implementation of OpenZeppelin's Governor contract, built to resemble Compound Finance's GovernorBravo contract. It anonymizes voting on proposals by severing the link between voter and vote, using a Nullifiable ZK Merkle Tree pioneered by Tornado Cash.

Simple Example

• Patrick is 1 of 5 public members of a DAO. The DAO want their voting directions to be kept hidden, but the final result to be public.
• A proposal is made to the GovernorZK contract.
• COMMITMENT PHASE
• Patrick wishes to vote on this proposal so he creates a secret and a nullifier locally, which he uses to generate a commitment. To register to vote, he sends this commitment to the contract from his known public address. The contract checks that the commitment is sent from Patrick's known address, and stores it. Every DAO member who wishes to participate in this proposal vote does this.
• VOTING PHASE
• Using ZK proofs, each DAO member can now vote anonymously from anonymous accounts by proving that they know a commitment without having to provide that commitment to the contract. Instead, they provide a ZK-proof that they know it, and their vote.

The link between Patrick's allow-listed address and the vote he casts is severed in the same way that the link between depositor and withdrawer is severed in Tornado Cash.

Current limitations

• 1 token = 1 vote doesn't work here as it risks giving away the identity of the voter. GovernorZK currently supports 1 allow-listed account = 1 vote, however, it is outsourced using the IVotes interface as defined by Openzeppelin. Some ideas on this:
  • Soulbound voting works well here, as well as rules like "Any balance above 0 = 1 vote" (NFTs for example).
  • This could be expanded by supporting tranches of votes (1, 10, 100, 1000, etc), similar to Tornado cash
• The Merkle Tree size is fixed to a height of 20 (2^20 leaves). Could we make this flexible depending on the use case?
• Foundry support is lacking given that most ZK libraries are written in JS/TS. Wen Ripped Jesus?
• Gas heavy: We'll target L2s initially, but efforts to reduce gas costs include:
  • Rolling Openzeppelin contracts into the main GovernorZK contract to pack reused storage.
  • Contribute/Rewrite zk-merkle-tree to optimize as much as possible (this could be a spinoff project).