Privacy Boost Protocol

Onchain Privacy Infrastructure for Enterprises

Website · Docs · Apache 2.0

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Privacy Boost enables private deposits, transfers, and withdrawals of ERC-20 tokens on any EVM chain. Zero-knowledge proofs (Groth16/BN254) hide sender, recipient, amount, and token type -- while preserving full self-custody.

This repository contains the smart contracts and ZK circuits that make up the core protocol.

Overview

contracts/
  src/
    PrivacyBoost.sol        Core shielded pool
    AuthRegistry.sol        EdDSA key registry
    TokenRegistry.sol       Token ID mapping
    PortalDelegate.sol      EIP-7702 delegate for portal deposit addresses
    gateway/                External call gateway
    verifier/               Groth16 proof verifiers
    hash/                   Poseidon2 and authorization-tree hashing
    interfaces/             Shared types, constants and contract interfaces
    lib/                    Epoch, deposit, portal, gift, digest and BabyJubJub libraries

frontend/
    epoch_circuit.go        Batched transfer & withdrawal circuit
    deposit_epoch_circuit.go  Batched deposit circuit
    forced_withdraw_circuit.go  Emergency exit circuit (client-side)

Circuit source

The circuit source matches backend release ceremony/v0.0.5 (commit b19e261440c38af65498a3e1aed0fab6e2428282), apart from the public Go module import path. It uses gnark v0.16.3 and gnark-crypto v0.21.0 and requires Go 1.25.13 or later. This identifies the circuit source for ceremony round 3, not a new contract deployment or a re-audit of this repository.

Key Properties

• Self-custodial -- Users can always exit via forced withdrawal using only their keys and onchain data, no server needed
• Private -- UTXO commitments hide all transfer details
• High throughput -- Epoch batching amortizes proof verification across many transactions
• EVM compatible -- Works with existing wallets and ERC-20 tokens

License

Apache 2.0 -- Copyright 2026 Sunnyside Labs Inc.