Architecture

System Overview

┌─────────────┐     ┌──────────────┐     ┌───────────────┐
│   Frontend   │────→│   Relayer    │────→│  Smart        │
│   (Browser)  │     │   Network    │     │  Contracts    │
└─────────────┘     └──────────────┘     └───────────────┘
       │                                        │
       │           ┌──────────────┐             │
       └──────────→│  ZK Prover   │─────────────┘
                   │  (Browser)   │
                   └──────────────┘

Core Contracts

Contract	Description
MainPool	Central pool — handles deposits, withdrawals, Merkle tree
ERC1967Proxy	Upgradeable proxy for MainPool
WithdrawVerifier	Groth16 ZK proof verifier (auto-generated)
DepositFactory	Creates one-time deposit addresses
RelayerRegistry	Relayer registration, staking, fee tracking
OFFToken	Governance and utility token (100M fixed supply)
Governance	On-chain proposal and voting system
Timelock	Treasury and execution delay for governance
Staking	Revenue share staking with lock multiplier (1x–2.5x)
TokenVesting	Vesting schedules for Treasury and Team allocations
PriceOracleV2	ETH→OFF price conversion — reads spot price directly from Uniswap V4 PoolManager via extsload (no oracle hooks needed)
Echoer	Utility for off-chain note relay

Fee Model

Relayers collect 100% of the ETH withdrawal fee from users. The protocol charges 0.3% of each withdrawal amount in OFF tokens, deducted from the relayer's stake. This OFF is distributed to stakers as revenue share.

ZK Circuit

The withdraw circuit (Groth16) proves:

• Knowledge of a valid (secret, nullifier) pair
• The corresponding leaf exists in the Merkle tree
• Public inputs: root, nullifier, recipient, token, amount, relayer, fee, newCommitment, changeAmount

9 public inputs • ~6,500 constraints • Poseidon hash

Token Support

Currently ETH only. ERC-20 tokens (USDT, USDC, DAI) planned for future release.