Dust Protocol

Dust is a private finance protocol on EVM chains. It has three main primitives: stealth transfers, privacy pools, and privacy swaps.

Stealth transfers let you send ETH or tokens to anyone without creating an on-chain link between sender and recipient. Every payment goes to a one-time address derived through ECDH — nobody watching the chain can associate it with the recipient's identity. .dust names sit on top so people can share a readable name instead of an address, and the whole mechanism works with any wallet without requiring the sender to run stealth-aware software.

DustPool V2 is a ZK-UTXO privacy pool with arbitrary-amount deposits and withdrawals. It uses a 2-in-2-out UTXO model with hidden amounts (Pedersen commitments), FFLONK proofs (no trusted setup, 22% cheaper than Groth16 with 8+ public signals), and an off-chain global Merkle tree maintained by a relayer. A 2-in-8-out split circuit provides denomination privacy by breaking withdrawals into common-sized chunks, defeating amount-based correlation. On top of this, an exclusion compliance system uses ZK proofs against a Sparse Merkle Tree of flagged commitments — users prove their commitment is NOT on the sanctions list without revealing which commitment they hold. Deposit screening via a Chainalysis oracle integration and a post-deposit cooldown period complete the compliance stack.

Privacy swaps let you trade ETH ↔ USDC without on-chain traceability. You deposit into a ZK pool, generate a proof in-browser that proves you own a deposit without revealing which one, and the swap executes through a Uniswap V4 hook that verifies the proof on-chain. Output lands at a stealth address with no linkage to whoever deposited.

---

Features

Stealth Transfers

• ECDH stealth addresses (ERC-5564 / ERC-6538) on secp256k1
• .dust names — human-readable payment endpoints with sub-address support
• Gasless claims via ERC-4337 (DustPaymaster), CREATE2 wallets, or EIP-7702 delegation
• PIN-based key derivation — wallet signature + 6-digit PIN through PBKDF2 (100K iterations)
• Private keys in memory only — React refs, never persisted to localStorage or sent to any server

DustPool V2 — ZK-UTXO Privacy Pool

• Arbitrary amounts — no fixed denominations for deposits/withdrawals
• 2-in-2-out UTXO circuit — 12,420 R1CS constraints, FFLONK proof system
• 2-in-8-out split circuit — 32,074 R1CS constraints, breaks withdrawals into common denomination chunks for amount privacy
• Denomination engine — auto-splits ETH withdrawals into chunks from a standard set (10, 5, 3, 2, 1, 0.5, ... down to 0.01 ETH)
• Batch deposits — up to 8 commitments per transaction
• Batch withdrawals — relayer shuffles execution order with timing jitter to prevent FIFO correlation
• Off-chain Merkle tree (depth 20, ~1M capacity) maintained by relayer with checkpoint persistence
• IndexedDB note encryption — AES-256-GCM via Web Crypto API, key derived from spending key

Compliance & Sanctions Screening

• Deposit screening — configurable compliance oracle (Chainalysis on mainnet, configurable oracle on testnet)
• Post-deposit cooldown — 1-hour standby period after deposit (Unshield-Only Standby pattern)
• ZK exclusion proofs — proves a commitment is NOT in the sanctions exclusion set without revealing the commitment
  • DustV2Compliance circuit: 13,543 R1CS constraints, FFLONK proof, 2 public signals (exclusionRoot, nullifier)
  • Sparse Merkle Tree (20 levels) of flagged commitments, maintained off-chain by relayer
  • Pre-call compliance pattern: verifyComplianceProof() sets flag, withdraw()/withdrawSplit() consumes it
  • BN254 field element guards on all public signals to prevent field overflow attacks
• View keys & selective disclosure — signed disclosure statements with CSV/PDF export for auditors

Privacy Swaps (DustSwap)

• Uniswap V4 hook — ZK proof verification in beforeSwap / afterSwap callbacks
• Atomic swap + proof verification — no intermediate step between proof and swap execution
• Separate pools — ETH and USDC with fixed denominations
• Chain ID binding — cross-chain replay prevention via public signal
• Relayer fee range check — prevents field wrap bypass attacks

Security Hardening

• Pausable — owner can pause all deposits/withdrawals
• Ownable2Step — two-step ownership transfer prevents accidental loss
• Chain ID as public signal — all circuits include block.chainid to prevent cross-chain replay
• Solvency tracking — totalDeposited per asset, prevents pool drain beyond deposits
• Duplicate commitment protection — each commitment can only be deposited once
• Null nullifier guard — prevents permanent slot poisoning via nullifier0 == bytes32(0)
• Persistent rate limiting — relayer cooldowns survive restarts via /tmp persistence
• Cross-chain nullifier guard — prevents same nullifier submission across chains

---

How It Works

Stealth Key Derivation

wallet_signature = sign("Dust Protocol stealth key", walletAddress)
entropy = PBKDF2(wallet_signature + PIN, salt_v2, 100000 iterations, SHA-512)
spendKey = entropy[0:32]   // secp256k1 scalar
viewKey  = entropy[32:64]  // secp256k1 scalar
metaAddress = (spendKey * G, viewKey * G)  // registered on ERC-6538

DustPool V2 — UTXO Model

Deposit:

• Browser generates spendingKey, nullifierKey from wallet signature + PIN
• commitment = Poseidon(amount, asset, spendingKey, nullifierKey, randomBlinding)
• Commitment queued on-chain, relayer inserts into off-chain Merkle tree

Withdraw (2-in-2-out):

• Browser fetches Merkle proof from relayer
• Generates FFLONK proof: proves ownership of 2 input UTXOs, creates 2 output UTXOs
• 9 public signals: [merkleRoot, nullifier0, nullifier1, outCommitment0, outCommitment1, publicAmount, publicAsset, recipient, chainId]
• Relayer submits on-chain — contract verifies proof, marks nullifiers spent, transfers funds

Split Withdraw (2-in-8-out):

• Same as above but creates up to 8 output commitments
• 15 public signals: [merkleRoot, null0, null1, outCommitment[8], publicAmount, publicAsset, recipient, chainId]
• Denomination engine auto-selects optimal split for maximum anonymity set overlap

Compliance Flow:

• Relayer maintains Sparse Merkle Tree of flagged (sanctioned) commitments
• Before withdraw, relayer calls verifyComplianceProof(exclusionRoot, nullifier, proof) per nullifier
• Circuit proves: (1) prover knows nullifier preimage, (2) commitment is NOT in exclusion set
• Contract sets complianceVerified[nullifier] = true, consumed by subsequent withdraw()/withdrawSplit()

ERC-4337 Claim Flow

1. Scanner detects stealth payment via ERC-5564 announcement log
2. Browser derives stealth private key (ECDH + spendKey)
3. POST /api/bundle — server builds UserOperation, DustPaymaster signs for gas
4. Browser signs userOpHash with stealth key (never leaves browser)
5. POST /api/bundle/submit — server calls entryPoint.handleOps()
6. EntryPoint deploys StealthAccount (CREATE2) and drains funds — one tx

---

Supported Networks

Network	Chain ID	Currency	Explorer
Ethereum Sepolia	11155111	ETH	sepolia.etherscan.io
Thanos Sepolia	111551119090	TON	explorer.thanos-sepolia.dustamak.network

.dust name registry is canonical on Ethereum Sepolia. DustSwap (privacy swaps) is currently on Ethereum Sepolia only.

Contract addresses: docs/CONTRACTS.md

---

Quick Start

npm install
cp .env.example .env.local
npm run dev

Environment Variables

# Required — relayer key for gas sponsorship
RELAYER_PRIVATE_KEY=<private-key>

# Optional — Alchemy for higher rate limits on Sepolia
NEXT_PUBLIC_ALCHEMY_SEPOLIA_RPC=https://eth-sepolia.g.alchemy.com/v2/<key>

# Optional — The Graph for faster name lookups
NEXT_PUBLIC_SUBGRAPH_URL_SEPOLIA=https://api.studio.thegraph.com/query/<id>/dust-protocol-sepolia/version/latest
NEXT_PUBLIC_USE_GRAPH=true

Running Tests

# Solidity (Foundry) — 126 tests
cd contracts/dustpool && forge test

# TypeScript — 301+ tests
npx vitest run

# Type check
npx tsc --noEmit

---

Project Structure

src/
├── app/
│   ├── page.tsx              # Landing page
│   ├── dashboard/            # Unified balance + pool UI
│   ├── onboarding/           # PIN setup + name registration
│   ├── swap/                 # Privacy swaps UI
│   ├── pools/                # Pool stats + contract info
│   ├── activities/           # Transaction history
│   ├── links/                # Payment link management
│   ├── settings/             # Account settings
│   ├── pay/[name]/           # Public pay page
│   └── api/
│       ├── v2/               # V2 relayer API routes
│       │   ├── withdraw/     # ZK withdrawal relay
│       │   ├── split-withdraw/ # Split withdrawal relay
│       │   ├── batch-withdraw/ # Batch withdrawal (shuffled + jittered)
│       │   ├── transfer/     # Internal pool transfer
│       │   ├── compliance/   # Exclusion compliance witness + proof
│       │   ├── tree/         # Merkle tree root + proof queries
│       │   ├── deposit/      # Deposit status
│       │   └── health/       # Relayer health check
│       ├── bundle/           # ERC-4337 UserOp build + submit
│       ├── resolve/[name]    # Stealth address generation
│       └── sponsor-*/        # Gas sponsorship endpoints
├── components/
│   ├── layout/               # Navbar
│   ├── dashboard/            # Balance cards, withdraw modal
│   ├── dustpool/             # V2 deposit/withdraw modals
│   ├── onboarding/           # OnboardingWizard
│   └── swap/                 # SwapInterface, PoolStats
├── hooks/
│   ├── stealth/              # useStealthScanner, useUnifiedBalance
│   ├── dustpool/v2/          # useV2Deposit, useV2Withdraw, useV2Compliance, useV2Disclosure
│   └── swap/                 # useDustSwap, usePoolQuote
├── lib/
│   ├── stealth/              # Core ECDH cryptography
│   ├── dustpool/v2/          # V2 contracts, relayer client, exclusion tree, compliance, disclosure
│   └── swap/zk/              # Privacy swap proof generation
└── contexts/
    └── AuthContext.tsx        # Wallet, stealth keys, PIN auth

contracts/
├── wallet/                   # StealthWallet + StealthAccount (48 tests)
├── dustpool/                 # DustPoolV2 + FFLONK verifiers (126 tests)
│   ├── src/
│   │   ├── DustPoolV2.sol           # Main privacy pool contract
│   │   ├── FFLONKVerifier.sol       # Transaction proof verifier (2-in-2-out, 9 signals)
│   │   ├── FFLONKSplitVerifier.sol  # Split proof verifier (2-in-8-out, 15 signals)
│   │   ├── FFLONKComplianceVerifier.sol  # Exclusion proof verifier (2 signals)
│   │   ├── ChainalysisScreener.sol  # Mainnet sanctions oracle wrapper
│   │   └── TestnetComplianceOracle.sol   # Configurable oracle for testnets
│   └── circuits/v2/
│       ├── DustV2Transaction.circom  # 2-in-2-out UTXO circuit (12,420 constraints)
│       ├── DustV2Split.circom        # 2-in-8-out split circuit (32,074 constraints)
│       └── DustV2Compliance.circom   # ZK exclusion proof circuit (13,543 constraints)
└── dustswap/                 # DustSwapHook + DustSwapPool + PrivateSwap circuit

---

Security Model

Layer	Mechanism
Stealth address generation	ECDH on secp256k1 — only the recipient can derive the private key
Key derivation	PBKDF2 (SHA-512, 100k iterations) over wallet signature + PIN — both required
Key isolation	Keys in React ref, never serialized, never sent to server
Gasless claim	Client signs userOpHash locally, server relays — key never leaves browser
ZK pool privacy	FFLONK proof — withdrawal is cryptographically unlinkable to deposit
Denomination privacy	2-in-8-out split into common chunks — defeats amount fingerprinting
Sanctions compliance	ZK exclusion proof against SMT of flagged commitments — no commitment reveal
Deposit screening	Chainalysis oracle integration with 1-hour post-deposit cooldown
Double-spend prevention	Nullifier stored on-chain, reuse rejected by contract
Cross-chain replay	Chain ID as public signal in all circuits + on-chain block.chainid check
Pool solvency	Per-asset deposit tracking, withdraw cannot exceed total deposits
Note encryption	AES-256-GCM (Web Crypto API) for IndexedDB note storage

---

Tech Stack

• Frontend: Next.js 14, React 18, Tailwind CSS
• Blockchain: wagmi v2, viem v2, ethers.js v5
• ZK: circom, snarkjs (FFLONK + Groth16 on BN254), circomlibjs (Poseidon, SMT)
• Contracts: Foundry, Solidity 0.8.20, Uniswap V4
• Account Abstraction: ERC-4337, EIP-7702
• Auth: Privy (social logins + embedded wallets), wagmi connectors (MetaMask, WalletConnect)
• Indexing: The Graph
• Standards: ERC-5564, ERC-6538, ERC-4337

---

Research

• Interactive No-Opt-In Stealth Addresses — zemse
• ERC-5564: Stealth Addresses
• ERC-6538: Stealth Meta-Address Registry
• Privacy Pools — Buterin et al.
• An Incomplete Guide to Stealth Addresses — Vitalik
• Uniswap V4 Hooks

---

License

MIT