ZeroLedger Contracts

A privacy-preserving ERC20 token vault system using zero-knowledge proofs for confidential transactions on Ethereum and compatible blockchains.

Overview

ZeroLedger enables private ERC20 token transfers by using cryptographic commitments and zero-knowledge proofs. Users can deposit, spend, and withdraw tokens while maintaining transaction privacy through the use of Circom circuits and PLONK proving system.

Key Features

• 🔒 Private Deposits: Deposit tokens with cryptographic commitments using Poseidon hashes
• 🔄 Confidential Spends: Transfer tokens between commitments using ZK proofs without revealing amounts
• 📊 Multiple Input/Output Support: Flexible transaction structures supporting various combinations (1-1, 1-2, 1-3, 2-1, 2-2, 2-3, 3-1, 3-2, 3-3, 8-1, 16-1)
• 💰 Fee Support: Configurable fees for transactions with dedicated fee recipients
• 🔐 Metadata Encryption: Optional encrypted metadata for commitments
• ⚡ PLONK Proving System: Efficient zero-knowledge proof generation and verification
• 🌐 Multi-Network Support: Deployable on Ethereum and compatible L2 networks
• 🛡️ Security: Built with OpenZeppelin contracts and comprehensive testing

Architecture

Smart Contracts

The ZeroLedger system consists of three main contracts designed for modularity and security:

• Vault: Core contract that stores and manages cryptographic commitments. Handles deposits, spends, and withdrawals while maintaining privacy through zero-knowledge proofs.

• Forwarder: Supports meta-transactions and batching operations. This contract is permissionless and enables users to execute transactions without paying gas fees directly, improving user experience and enabling complex transaction batching.

• ProtocolManager: Manages protocol-level parameters like fees and max protocol tvl.

• Administrator: Manages protocol contracts administrative functions like upgrades or emergency pausing

Management & Security

Multisig Governance: All administrative functions, including fee updates, contract upgrades, and security measures, are managed through multisig wallets. This ensures that no single entity can make critical changes to the protocol.

• Admin Multisig: Controls protocol roles management
• Maintainer Multisig: Controls protocol contracts upgrades
• Security Council Multisig: Manages emergency pauses and security functions
• Treasury Manager Multisig: Controls fee parameters and treasury operations

Zero-Knowledge Circuits

• Deposit Circuit: Validates 3 input commitments sum to total deposit amount
• Spend Circuits: Multiple variants supporting different input/output combinations:
  • spend_11: 1 input, 1 output
  • spend_12: 1 input, 2 outputs
  • spend_13: 1 input, 3 outputs
  • spend_21: 2 inputs, 1 output
  • spend_22: 2 inputs, 2 outputs
  • spend_23: 2 inputs, 3 outputs
  • spend_31: 3 inputs, 1 output
  • spend_32: 3 inputs, 2 outputs
  • spend_33: 3 inputs, 3 outputs
  • spend_82: 8 inputs, 1 outputs
  • spend_161: 16 inputs, 1 output

Requirements

• Git
• Node.js (v18 or higher)
• Foundry for unit testing and development
• Hardhat for integration tests & deployment

Quick Start

1.Clone and install dependencies:

git clone https://github.com/zeroledger/contracts.git
cd contracts
npm install
npx husky install

2.Install Foundry dependencies:

forge install foundry-rs/forge-std

3.Set up environment variables:

cp .env.example .env
# Edit .env with your configuration

Available Scripts

Development

• npm run compile - Compile contracts with Hardhat
• npm run format - Format Solidity code with Forge
• npm run lint - Lint Solidity code with Solhint
• npm run gas - Generate gas report

Testing

• npm run test - Run all tests (Foundry + Hardhat)
• npm run unit - Run all Foundry unit tests
• npm run int - Run Hardhat integration tests

Deployment

• npm run deploy {network} - Initial deploy to specified network

Maintenance

• npm run clean - Clean all build artifacts and dependencies
• VERSION_TAG={Version} npx hardhat ignition deploy ./ignition/modules/{Vault|Forwarder|ProtocolManager}.module.ts --network {network} - Deploy new module version
• FEES_CONFIG="{deposit};{spend};{withdraw}" TOKEN={token} npm run prepareFeesParams {network} - create ready-to-set fees config for erc20 token

Project Structure

contracts/
├── src/                      # Smart contract source files
│   ├── Administrator.sol     # Contract to admin roles for Forwarder, Vault, ProtocolManager contract administration
│   ├── Forwarder.sol         # Forwarder contract with ERC6492 support
│   ├── ProtocolManager.sol   # Contract to manage protocol parameters
│   ├── Vault.sol             # Main vault contract
│   ├── Vault.types.sol       # Vault types & interfaces
│   ├── Verifiers.sol          # ZK proof verifiers umbrella contract
│   ├── Roles.lib.sol         # Roles constants
│   └── Inputs.lib.sol        # Input utilities
├── helpers/                  # Helpers contracts
│   ├── MockERC20.sol         # Test token
│   └── Proxy.sol/            # ERC1967Proxy import
├── ignition/                 # Zero-knowledge circuits
│   ├── modules/              # hardhat ignition deployment modules
│   └── deployments/          # deployments artifacts
├── test/                     # Foundry unit tests
├── integration/              # Hardhat integration tests
├── circuits/                 # Zero-knowledge circuits (git module)
├── lib/                      # Foundry dependencies (git module)
└── abi/                      # Contract ABIs

Environment Variables

Create a .env based on .env.example

Supported Networks

• Local Development: Hardhat, Localhost
• Testnets: BaseSepolia

Networks are configurable via hardhat.config.js

Security

• Audited Dependencies: Uses OpenZeppelin & solady contracts
• Reentrancy Protection: Built-in guards against reentrancy attacks
• Access Control: Proper authorization mechanisms with multisig governance
• Zero-Knowledge Proofs: Cryptographic privacy guarantees
• Comprehensive Testing: Extensive test coverage: In progress

Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Resources

• ZeroLedger Protocol Documentation
• Foundry Documentation
• Hardhat Documentation
• Circom Documentation
• OpenZeppelin Contracts
• Solady Documentation
• Solidity Documentation

License

This project is licensed under the GNU v3.0 License - see the LICENSE file for details.

Support

If you encounter any issues or have questions:

• Open an issue
• Check the documentation
• Join our community discussions telegram

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Note: This is experimental software. Always audit your smart contracts before deploying to production networks.