ZK-Based Governance & Anonymous Voting System

## ROLE
You are a cryptographic voting systems designer who builds private, verifiable governance systems for DAOs and decentralized organizations. You understand the complex requirements of electronic voting: privacy, verifiability, coercion resistance, and the unique challenges of blockchain-based governance.

## OBJECTIVE
Design a zero-knowledge proof-based governance and voting system that provides ballot secrecy, universal verifiability, and resistance to vote buying and coercion for decentralized organizations.

## TASK
Create a comprehensive ZK voting system:

### Voting System Requirements

**Core Properties:**
1. **Ballot secrecy:** No one can learn how any specific person voted
2. **Eligibility:** Only qualified members can vote
3. **Uniqueness:** Each member votes at most once
4. **Universal verifiability:** Anyone can verify the election result is correct
5. **Individual verifiability:** Each voter can confirm their vote was counted
6. **Coercion resistance:** Voters cannot prove how they voted to a third party
7. **Fairness:** No partial results are revealed before voting ends

### System Architecture

**1. Voter Registration**
```
Registration phase:
1. Eligible voter generates a secret key pair
2. Voter submits public key to registration contract
   (or: token holders are automatically registered)
3. Public keys are added to a Merkle tree of eligible voters
4. Merkle root published as the voter set commitment
```

**Eligibility Options:**
- Token-weighted voting (1 token = 1 vote, weighted by balance)
- One-person-one-vote (identity-based, requires ZK identity)
- Quadratic voting (vote power = square root of tokens committed)
- Conviction voting (time-weighted commitment)
- Delegated voting with privacy (delegate without revealing to whom)

**2. Voting Phase**

**Simple Private Vote:**
```
Voter generates ZK proof:
Private inputs: secret_key, merkle_path, vote_choice
Public inputs: merkle_root, nullifier, encrypted_vote

Proof proves:
1. Voter knows a secret key in the registered voter set (eligibility)
2. Nullifier is correctly derived from secret key (prevents double voting)
3. Encrypted vote correctly encodes the voter's choice

Encrypted vote uses election public key (decrypted only after voting ends)
```

**Token-Weighted Private Vote:**
```
Additional proof requirements:
- Prove token balance at snapshot block
- Prove vote weight matches token balance
- Prevent splitting tokens to vote multiple times
- Handle delegation of voting power
```

**3. Tallying Phase**

**Option A: Homomorphic Tallying**
- Votes encrypted with homomorphic scheme
- Encrypted votes can be summed without decryption
- Final tally decrypted by threshold key holders
- ZK proof that decryption was performed correctly
- Individual votes never decrypted

**Option B: Commit-Reveal Tallying**
- Voting phase: Submit encrypted votes with ZK proof of validity
- Reveal phase: After deadline, submit decryption keys
- Tally computed from revealed votes
- Less private (votes eventually revealed, but too late for coercion)

**Option C: Shuffle-Based Tallying**
- Encrypted votes shuffled by mix network
- Each shuffler provides ZK proof of correct shuffle
- Shuffled votes decrypted (order broken, unlinkable to voters)
- Tally computed from shuffled, decrypted votes

### Advanced Features

**1. Coercion Resistance**
- Problem: Voter can prove to a coercer how they voted
- Solution: Re-voting capability
  - Voter can override their vote (latest vote counts)
  - Coercer cannot tell if the vote was overridden
  - Implemented via updatable nullifiers
- Solution: Deniable encryption
  - Voter can produce fake decryption that shows any vote

**2. Vote Delegation with Privacy**
- Delegate voting power without revealing the delegate
- ZK proof that delegation is valid
- Delegate votes with combined power
- Delegation revocation
- Liquid democracy with privacy

**3. Quadratic Voting with Privacy**
- Prove you are spending N^2 tokens for N votes on a proposal
- Prevent Sybil attacks (splitting identity for cheaper votes)
- Budget management across multiple proposals
- ZK proof of correct quadratic cost calculation

### Smart Contract Architecture

**Contracts:**
- VoterRegistry: Manages eligible voter set (Merkle tree)
- Proposal: Stores proposal details and parameters
- VoteVerifier: On-chain ZK proof verification
- Tally: Computes and publishes results
- Governance: Executes approved proposals

**On-Chain vs. Off-Chain:**
- On-chain: Proof verification, nullifier tracking, final tally
- Off-chain: Proof generation (client-side), encrypted vote storage (optional)
- Hybrid: IPFS for encrypted votes, on-chain for proofs and results

### User Experience

**Voting Interface:**
- Connect wallet
- View proposals and discussion
- Select vote choice
- Proof generation in browser (show progress, ~10-30 seconds)
- Submit vote transaction (or through relayer for IP privacy)
- Verify vote was included after tallying
- View results

**Wallet Integration:**
- Private key management for voting keys
- Backup and recovery of voting keys
- Multi-device support
- Hardware wallet signing support

### Security Analysis
- Double voting prevention (nullifier set)
- Vote manipulation (ZK proof soundness)
- Censorship resistance (relayer network, forced inclusion)
- Timing attacks (all votes processed in the same period)
- Front-running prevention (encrypted votes)
- Admin key risks (minimize admin powers, use timelock)
- Smart contract audit requirements

### Governance Process Design
- Proposal creation threshold
- Discussion period before voting
- Voting duration
- Quorum requirements
- Majority thresholds (simple, supermajority)
- Execution delay (timelock after approval)
- Emergency procedures
- Constitutional constraints (what cannot be changed by vote)