GrimSwap Contracts

Privacy-preserving swap contracts for Uniswap v4 on Unichain, powered by Groth16 ZK-SNARKs.

Architecture (V3 - Production)

User deposits ETH
       │
       ▼
  ┌─────────┐     ZK Proof      ┌──────────────┐     Swap      ┌────────────┐
  │ GrimPool │ ───────────────►  │ GrimSwapRouter│ ──────────►  │ Uniswap V4 │
  │ (Deposit │   via Relayer     │  (Atomic Tx)  │              │  PoolManager│
  │  + Tree) │                   └──────────────┘              └─────┬──────┘
  └─────────┘                                                        │
                                                          ┌──────────┘
                                                          ▼
                                                   ┌─────────────┐
                                                   │ GrimSwapZK  │
                                                   │  (V4 Hook)  │
                                                   │  Verifies   │
                                                   │  ZK proof + │
                                                   │  Routes to  │
                                                   │  stealth    │
                                                   └─────────────┘
                                                          │
                                                          ▼
                                                   Stealth Address
                                                   receives output tokens

Contracts

Contract	Description
GrimPool	Deposit pool with Poseidon Merkle tree (20 levels, ~1M deposits)
GrimSwapZK	Uniswap v4 hook - dual-mode: passthrough for regular swaps, ZK verification for private swaps
GrimSwapRouter	Atomic orchestrator: releases ETH from GrimPool + swaps in one tx
Groth16Verifier	On-chain ZK proof verifier (auto-generated from circuits)

Deployed Addresses (Unichain Sepolia)

Contract	Address
PoolManager (Uniswap)	0x00B036B58a818B1BC34d502D3fE730Db729e62AC
PoolSwapTest (Uniswap)	0x9140a78c1A137c7fF1c151EC8231272aF78a99A4
PoolModifyLiquidityTest	0x5fa728C0A5cfd51BEe4B060773f50554c0C8A7AB
GrimPool	0xEAB5E7B4e715A22E8c114B7476eeC15770B582bb
GrimSwapZK (Hook)	0x3bee7D1A5914d1ccD34D2a2d00C359D0746400C4
GrimSwapRouter	0xC13a6a504da21aD23c748f08d3E991621D42DA4F
Groth16Verifier	0xF7D14b744935cE34a210D7513471a8E6d6e696a0
USDC	0x31d0220469e10c4E71834a79b1f276d740d3768F

Active Pools

Pool	Pool ID	Fee	TickSpacing	Status
ETH/USDC (GrimSwap)	0xca4150cd3ab144877e0dee5630129d84b986daa7ef5f287729e2f2da00c3fe38	3000	60	Active with liquidity
ETH/USDC (Vanilla)	0x1927686e9757bb312fc499e480536d466c788dcdc86a1b62c82643157f05b603	3000	60	Active

Privacy Guarantees

• Sender hidden: ZK proof proves deposit membership without revealing which deposit
• Recipient hidden: Output goes to one-time stealth address
• Gas payer hidden: Relayer submits transaction, user never touches chain
• Double-spend prevented: Nullifier hash marks each deposit as spent
• Atomic execution: Router reverts everything if ZK proof is invalid

Dual-Mode Hook

GrimSwapZK operates in two modes:

• Regular swap (hookData.length == 0): Passthrough, no ZK verification
• Private swap (hookData.length > 0): Full ZK proof verification + stealth routing

This allows the same pool to serve both regular and private swaps.

Development

# Install
forge install

# Build
forge build

# Test
forge test

Creating a Pool (Frontend)

To create a new pool with the GrimSwapZK hook:

1. Call poolManager.initialize(poolKey, sqrtPriceX96) with hook = GrimSwapZK address
2. Deploy a liquidity helper (or use the DirectLiquidityAdder pattern in script/AddLiquidityDirect.s.sol)
3. Add liquidity with explicit liquidityDelta (the simplified calculation in PoolTestHelper doesn't work for tokens with different decimals like ETH/USDC)

Important: For ETH/USDC pools, do NOT use PoolTestHelper.addLiquidity() as the simplified liquidity calculation breaks for tokens with different decimal places. Use DirectLiquidityAdder with an explicit liquidityDelta instead.

sqrtPriceX96 Reference

Price (ETH/USDC)	sqrtPriceX96
$2000	3543191142285914205922034
$3000	4339505028714986015908034

License

MIT