Privacy & Governance Contracts

Three contracts implementing privacy-preserving payments and sybil-resistant governance on Starknet.

StealthRegistry

File: contracts/src/stealth/StealthRegistry.cairo (240 LOC)

ERC-5564-inspired stealth address system for privacy-preserving transfers on Starknet.

How It Works

1. Recipient registers meta-address (spending_pubkey, viewing_pubkey)
2. Sender generates ephemeral keypair, computes shared secret
3. Sender sends funds to derived stealth address
4. Sender calls announce() with ephemeral_pubkey + view_tag
5. Recipient scans announcements via view_tag to detect funds

Recipients register once; senders can transfer privately to any registered user without revealing the link between sender and recipient on-chain.

Interface

Events

Design Decisions

• Open announce(): Any address can publish announcements (per ERC-5564 spec). This prevents sender deanonymization through access control.
• View tags: 4-byte prefix of shared secret hash enables fast scanning without full decryption of every announcement.
• Append-only log: Announcements are stored sequentially for efficient indexing and pagination.

ConfidentialPool

File: contracts/src/privacy/ConfidentialPool.cairo (324 LOC)

Commitment-based deposit/withdraw system inspired by Vitalik's Privacy Pools paper. Uses Poseidon hash commitments and nullifiers.

How It Works

Deposit:
  commitment = poseidon(secret, nullifier_preimage, amount, token)
  user deposits fixed amount + commitment into pool

Withdraw:
  nullifier = poseidon(nullifier_preimage)
  user reveals preimage → contract reconstructs commitment
  if commitment exists + nullifier unspent → transfer tokens

Interface

Security Properties

• Double-spend prevention: Nullifier registry ensures each commitment can only be withdrawn once.
• Commitment uniqueness: Each commitment can only be deposited once.
• ReentrancyGuard: Manual reentrancy lock on deposit and withdraw.
• CEI pattern: Nullifier marked as spent before external token transfer.
• felt252 overflow protection: Deposit amount validated against field prime.
• Association sets: Owner can block specific commitments for regulatory compliance.
• Pausable: Emergency halt for deposit/withdraw operations.

v1 Limitation

v1 uses plaintext preimage revelation — withdrawal calldata reveals the secret and nullifier_preimage on-chain, allowing deposit-withdrawal linking by observers. This provides pseudonymous transfers, not full privacy. v2 will integrate STARK proofs for true zero-knowledge withdrawal.

DaoGovernance (Glacis Protocol)

File: glacis-protocol/contracts/src/dao_governance.cairo (435 LOC)

Sybil-resistant governance where each verified human gets exactly one vote. Voting power is gated by HumanAttestation SBT — no token-weighted plutocracy.

How It Works

1. Verified human calls propose() with target contract call
2. After voting_delay, voting opens for voting_period
3. Each verified human votes once (for / against / abstain)
4. If quorum met and for > against → proposal succeeds
5. queue() schedules execution via TimelockController
6. execute() after timelock delay

Proposal States

PENDING (0) → ACTIVE (1) → DEFEATED (2) or SUCCEEDED (3)
                                          ↓
                                     QUEUED (4) → EXECUTED (5)
                                          ↓
                                     CANCELLED (6)

Interface

Security (Audit Fixes)

• Parameter snapshotting: Governance params (quorum, voting_period) are snapshotted per proposal at creation time. This prevents an admin from changing quorum mid-vote to manipulate outcomes.
• ParameterUpdated events: All governance parameter changes emit events for transparency.
• Cancel supports QUEUED state: Proposers and admins can cancel proposals even after they've been queued to the timelock.

Integration with Glacis

DaoGovernance requires IHumanAttestation to verify voters. Only wallets holding a valid (non-expired, non-revoked) HumanAttestation SBT can propose or vote. This creates one-person-one-vote governance without token accumulation attacks.

Test Coverage

Deployment Status