Privacy-Preserving Swaps on Uniswap v4
GrimSwap is the first privacy-preserving DEX built on Uniswap v4, combining cryptographic dark arts to hide both sender identity and recipient address. We bring Tornado Cash-level privacy to DeFi swaps—without leaving the Ethereum ecosystem.
┌─────────────────────────────────────────────────────────────┐
│ THE PRIVACY PROBLEM │
├─────────────────────────────────────────────────────────────┤
│ │
│ Every swap on Uniswap is 100% PUBLIC: │
│ │
│ • WHO swapped → Your wallet exposed │
│ • WHAT amount → Your strategy revealed │
│ • WHERE it went → Your recipient known │
│ │
│ Result: $1.3B+ extracted by MEV bots annually │
│ │
└─────────────────────────────────────────────────────────────┘
↓ GrimSwap ↓
┌─────────────────────────────────────────────────────────────┐
│ THE GRIMSWAP SOLUTION │
├─────────────────────────────────────────────────────────────┤
│ │
│ 🔐 ZK-SNARKs (Groth16) → WHO? Proves membership, hides ID │
│ 👻 Stealth Addresses → WHERE? Unlinkable address │
│ ⚡ Uniswap v4 Hooks → HOW? Seamless integration │
│ │
│ Result: Complete swap privacy, verified on-chain │
│ │
└─────────────────────────────────────────────────────────────┘
| Direction | Input | Output | TX Hash |
|---|---|---|---|
| ETH → USDC | 0.001 ETH | 224.36 USDC | 0x22b313f8... |
| USDC → ETH | 1 USDC | ~0.0005 ETH | 0xbf064fbc... |
| Metric | Value |
|---|---|
| Network | Unichain Sepolia |
| ZK Proof Time | ~1 second |
| Status | ON-CHAIN VERIFIED |
| Feature | Status | Description |
|---|---|---|
| ZK Proof Verification | PASS | Groth16 proof verified on-chain |
| Poseidon Commitment | PASS | ZK-friendly hash for deposits |
| Merkle Tree | PASS | 20 levels (~1M anonymity set) |
| Nullifier System | PASS | Double-spend prevention |
| Stealth Address | PASS | Recipient privacy via ERC-5564 |
| Track | Prize |
|---|---|
| Uniswap v4 Privacy DeFi | $5,000 |
| ETHGlobal Finalist | $1,000+ |
ETHGlobal HackMoney 2026
We believe financial privacy is a fundamental right, not a privilege. GrimSwap gives DeFi users the same privacy that Tornado Cash gave Ethereum users—but integrated directly into Uniswap's liquidity and composability.
|
Solidity smart contracts for Uniswap v4 hooks
|
Circom ZK circuits +
|
|
Vite + React frontend application
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Integration tests & examples
|
|
Transaction relay service — live
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TypeScript SDK for privacy primitives
|
┌─────────────────────────────────────────────────────────────────────┐
│ GrimSwap ZK Flow │
├─────────────────────────────────────────────────────────────────────┤
│ │
│ 1. DEPOSIT │
│ User ──deposit(commitment)──► GrimPool │
│ commitment = Poseidon(nullifier, secret, amount) │
│ │ │
│ ▼ │
│ Merkle Tree │
│ (20 levels, ~1M deposits) │
│ │
│ 2. PRIVATE SWAP │
│ User ──generates ZK proof──► Groth16 Proof (~1 second) │
│ (proves deposit membership without revealing which one) │
│ │ │
│ ▼ │
│ Relayer ──submits tx──► GrimSwapZK Hook ──verify──► Groth16 │
│ (hides gas payer) (Uniswap v4) Verifier │
│ │ │
│ ▼ │
│ Uniswap v4 Pool │
│ │ │
│ ▼ │
│ Stealth Address ◄──tokens───────┘ │
│ (recipient hidden via ERC-5564) │
│ │
└─────────────────────────────────────────────────────────────────────┘
| Feature | Technology | Privacy Guarantee |
|---|---|---|
| Sender Privacy | ZK-SNARKs (Groth16) | Hidden among ALL depositors |
| Recipient Privacy | ERC-5564 Stealth Addresses | Unlinkable one-time address |
| Amount Privacy | Fixed Denominations | No correlation attacks |
| Gas Payer Privacy | Relayer Network | Transaction origin hidden |
| Double-Spend Prevention | Nullifier System | Unique per withdrawal |
GrimSwap provides unlinkability, not invisibility. This is the same model used by Tornado Cash, Railgun, and other proven privacy protocols.
What's Visible vs Hidden
| Step | What's Visible On-Chain | What's Hidden |
|---|---|---|
| Deposit | User address, amount, commitment hash | — |
| ZK Proof Generation | Nothing (runs client-side) | Everything |
| Swap Execution | Relayer address, swap output | Which deposit was used |
| Token Receipt | Stealth address receives tokens | Link to original depositor |
Alice deposits 0.01 ETH ──┐
Bob deposits 0.01 ETH ──┼──► GrimPool (Anonymity Set)
Carol deposits 0.01 ETH ──┘
│
▼ ZK Proof proves membership
│ without revealing which one
▼
Swap Output ──────────────► Stealth Address (unlinkable)
What an observer sees:
- "Alice, Bob, and Carol each deposited to GrimPool"
- "Someone withdrew and swapped to a stealth address"
What an observer CANNOT prove:
- Which specific deposit was used
- Any link between depositor ↔ stealth address recipient
| Deposits in Pool | Privacy Level |
|---|---|
| 1 deposit | No privacy (trivial to link) |
| 10 deposits | Weak privacy |
| 100 deposits | Good privacy |
| 1,000+ deposits | Strong privacy |
The deposit being visible is expected. The ZK proof ensures no one can link it to the output.
| Layer | Technology |
|---|---|
| Blockchain | Unichain (Uniswap's L2) |
| AMM | Uniswap v4 Hooks |
| ZK Proofs | Groth16 (snarkjs/circom) |
| Hash Function | Poseidon (ZK-friendly) |
| Smart Contracts | Solidity 0.8.26, Foundry |
| SDK | TypeScript, viem, snarkjs |
| Frontend | Vite, React, wagmi |
| Contract | Address |
|---|---|
| GrimSwapZK Hook | 0x6AFe3f3B81d6a22948800C924b2e9031e76E00C4 |
| GrimPoolMultiToken | 0x6777cfe2A72669dA5a8087181e42CA3dB29e7710 |
| GrimSwapRouterV2 | 0x5EE78E89A0d5B4669b05aC8B7D7ea054a08f555f |
| Groth16Verifier | 0xF7D14b744935cE34a210D7513471a8E6d6e696a0 |
| USDC | 0x31d0220469e10c4E71834a79b1f276d740d3768F |
| Contract | Address |
|---|---|
| StealthAddressRegistry | 0xA9e4ED4183b3B3cC364cF82dA7982D5ABE956307 |
| ERC5564Announcer | 0x42013A72753F6EC28e27582D4cDb8425b44fd311 |
| Service | URL |
|---|---|
| Relayer | https://services.grimswap.com |
| SDK | @grimswap/circuits |
- First ZK-SNARK verified swap on Uniswap v4
- First Tornado Cash-style privacy on a DEX
- First stealth address swap outputs
- First privacy Uniswap v4 hook
- First privacy DEX on Unichain
We're building the future of private DeFi. Here's how you can join:
- 🔧 Contribute: Check out our repos and submit PRs
- 🧪 Test: Try private swaps on Unichain Sepolia
- 📦 Build: Use our circuits and SDK in your dApps
- 💬 Discuss: Open issues for features & feedback
# Clone and run the full ZK swap test
git clone https://github.com/grimswap/grimswap-test.git
cd grimswap-test
npm install
# Set your private key and run
export PRIVATE_KEY=0x...
npm run test:zkswapIntegrate private swaps into your app with the @grimswap/circuits SDK.
npm install @grimswap/circuits
npx grimswap-copy-circuits public/circuitsimport {
createDepositNote,
formatCommitmentForContract,
executePrivateSwap,
GRIM_POOL_ABI,
UNICHAIN_SEPOLIA_ADDRESSES,
} from "@grimswap/circuits";
// 1. Deposit ETH
const note = await createDepositNote(parseEther("1"));
await contract.deposit(formatCommitmentForContract(note.commitment), { value: parseEther("1") });
note.leafIndex = /* from Deposit event */;
// 2. Private swap (one call — builds tree, generates proof, submits to relayer)
const wasm = await fetch("/circuits/privateSwap.wasm").then(r => r.arrayBuffer());
const zkey = await fetch("/circuits/privateSwap.zkey").then(r => r.arrayBuffer());
const result = await executePrivateSwap({
note,
recipient: stealthAddress,
poolKey: {
currency0: "0x0000000000000000000000000000000000000000",
currency1: tokenAddress,
fee: 3000,
tickSpacing: 60,
hooks: UNICHAIN_SEPOLIA_ADDRESSES.grimSwapZK,
},
zeroForOne: true,
amountSpecified: -note.amount,
wasmBuffer: wasm,
zkeyBuffer: zkey,
});
console.log(result.txHash); // done!| Feature | Function |
|---|---|
| Create deposits | createDepositNote(), formatCommitmentForContract() |
| Read chain state | fetchDeposits(), getDepositCount() |
| ZK proof (browser) | generateProofFromBuffers() |
| Full private swap | executePrivateSwap() — single call |
| Relayer client | submitToRelayer(), getRelayerInfo() |
| Stealth addresses | generateStealthKeys(), generateStealthAddress() |
| All ABIs | GRIM_POOL_ABI, GRIM_SWAP_ROUTER_ABI, etc. |
| All addresses | UNICHAIN_SEPOLIA_ADDRESSES |
Full integration guide: grimswap-circuits/README.md
GrimSwap — The Dark Arts of DeFi
Privacy isn't about hiding. It's about choice.
