DeFi Lending Protocol on Oasis Sapphire Network

A production-ready DeFi lending and borrowing protocol built on the Oasis Sapphire Network with privacy features and confidential computing capabilities.

🌟 Features

Core Functionality

• Multi-Asset Support: Deposit and borrow ETH, USDC, DAI, and other ERC20 tokens
• Interest-Bearing Tokens: Receive aTokens that automatically accrue interest
• Dynamic Interest Rates: Rates adjust based on utilization and market conditions
• Collateral Management: Multi-collateral support with configurable LTV ratios
• Liquidation Engine: Automated liquidation of unhealthy positions
• Flash Loans: Execute flash loans for arbitrage and other DeFi strategies

Privacy Features (Sapphire-Specific)

• Confidential Balances: User balances are encrypted and private
• Hidden Collateral Ratios: Collateral ratios are not publicly visible
• MEV Protection: Transactions are protected from front-running
• Private Health Factors: Health factors are calculated confidentially
• Confidential Liquidations: Liquidation processes maintain privacy

Security Features

• Upgradeable Contracts: UUPS proxy pattern for future upgrades
• Access Control: Role-based permissions for admin functions
• Pause Mechanism: Emergency pause functionality
• Reentrancy Protection: Secure against reentrancy attacks
• Oracle Integration: Chainlink price feeds with fallback mechanisms

🏗️ Architecture

defi-sapphire-lending/
├── contracts/
│   ├── core/
│   │   └── LendingPool.sol          # Main lending pool contract
│   ├── interfaces/
│   │   ├── ILendingPool.sol         # Lending pool interface
│   │   ├── IPriceOracle.sol         # Price oracle interface
│   │   └── IInterestRateModel.sol   # Interest rate model interface
│   ├── libraries/
│   │   ├── DataTypes.sol            # Data structures
│   │   └── Math.sol                 # Mathematical operations
│   ├── oracles/
│   │   └── ChainlinkPriceOracle.sol # Price oracle implementation
│   └── tokens/
│       └── aToken.sol               # Interest-bearing token
├── scripts/
│   └── deploy.js                    # Deployment script
├── test/                            # Test files
├── hardhat.config.ts               # Hardhat configuration
└── package.json                    # Dependencies

🚀 Quick Start

Prerequisites

• Node.js (v16 or higher)
• npm or yarn
• Hardhat
• Sapphire testnet ETH

Installation

1. Clone the repository

   git clone <repository-url>
   cd defi-sapphire-lending

2. Install dependencies

   npm install

3. Set up environment variables

   cp .env.example .env

   Edit .env with your configuration:

   PRIVATE_KEY=your_private_key_here
   SAPPHIRE_API_KEY=your_sapphire_api_key_here

4. Compile contracts

   npm run compile

Deployment

Local Development

npm run deploy:local

Sapphire Testnet

npm run deploy:sapphire-testnet

Sapphire Mainnet

npm run deploy:sapphire-mainnet

📖 Usage

Basic Operations

1. Deposit Assets

// Deposit USDC
await lendingPool.deposit(
    usdcAddress,
    ethers.parseUnits("1000", 6), // 1000 USDC
    userAddress,
    0 // referral code
);

2. Borrow Assets

// Borrow DAI against USDC collateral
await lendingPool.borrow(
    daiAddress,
    ethers.parseEther("500"), // 500 DAI
    2, // variable rate mode
    0, // referral code
    userAddress
);

3. Repay Debt

// Repay borrowed DAI
await lendingPool.repay(
    daiAddress,
    ethers.parseEther("100"), // 100 DAI
    2, // variable rate mode
    userAddress
);

4. Withdraw Assets

// Withdraw USDC
await lendingPool.withdraw(
    usdcAddress,
    ethers.parseUnits("500", 6), // 500 USDC
    userAddress
);

Advanced Operations

Flash Loans

// Execute flash loan
await lendingPool.flashLoan(
    receiverAddress,
    [usdcAddress],
    [ethers.parseUnits("10000", 6)],
    [0], // no debt mode
    userAddress,
    "0x", // params
    0 // referral code
);

Liquidation

// Liquidate unhealthy position
await lendingPool.liquidationCall(
    collateralAsset,
    debtAsset,
    userAddress,
    debtToCover,
    false // receive aToken
);

🔧 Configuration

Reserve Parameters

Each reserve can be configured with the following parameters:

• Collateral Factor: Maximum percentage of collateral value that can be borrowed (e.g., 80%)
• Liquidation Threshold: Health factor threshold for liquidation (e.g., 85%)
• Borrow Factor: Maximum percentage of available liquidity that can be borrowed
• Interest Rate Parameters: Base rate, kink rate, and multiplier for dynamic rates

Oracle Configuration

• Heartbeat: Maximum time between price updates
• Deviation Threshold: Maximum allowed price deviation
• Staleness Threshold: Maximum age of price data
• Price Confidence: Confidence interval for price accuracy

🧪 Testing

Run Tests

npm test

Test Coverage

npm run coverage

Gas Optimization

npm run gas-report

🔒 Security

Audit Status

• External audit pending
• Internal review completed
• Bug bounty program planned

Security Features

• Reentrancy protection on all external calls
• Access control with role-based permissions
• Emergency pause functionality
• Oracle manipulation protection
• Flash loan attack prevention

Best Practices

• Use latest OpenZeppelin contracts
• Follow Solidity security guidelines
• Implement proper access controls
• Use safe math operations
• Validate all inputs

📊 Monitoring

Key Metrics

• Total Value Locked (TVL)
• Utilization rates
• Interest rates
• Liquidation events
• Flash loan volume

Health Checks

• Reserve health factors
• Oracle price staleness
• Protocol solvency
• Gas usage optimization

🚨 Emergency Procedures

Pause Protocol

// Pause all operations
await lendingPool.pause();

Emergency Withdraw

// Emergency withdraw (admin only)
await lendingPool.emergencyWithdraw(asset, amount, to);

Oracle Fallback

// Switch to fallback oracle
await priceOracle.setFallbackOracle(fallbackOracleAddress);

🔄 Upgrades

Upgrade Process

1. Deploy new implementation
2. Verify implementation
3. Upgrade proxy
4. Verify upgrade

// Upgrade LendingPool
await upgrades.upgradeProxy(lendingPoolAddress, newLendingPoolImpl);

📈 Analytics

Integration

• The Graph for indexing
• Dune Analytics for dashboards
• Custom analytics dashboard

Key Queries

• User deposit/withdrawal patterns
• Borrowing trends
• Liquidation analysis
• Interest rate evolution

🤝 Contributing

Development Setup

1. Fork the repository
2. Create feature branch
3. Make changes
4. Add tests
5. Submit pull request

Code Standards

• Follow Solidity style guide
• Add comprehensive tests
• Update documentation
• Include gas optimization

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🆘 Support

Documentation

• Technical Documentation
• API Reference
• Integration Guide

Community

• Discord
• Telegram
• Twitter

Bug Reports

• GitHub Issues
• Security Issues

🙏 Acknowledgments

• OpenZeppelin for secure contract libraries
• Chainlink for price oracle infrastructure
• Oasis Foundation for Sapphire Network
• Hardhat team for development tools

📝 Changelog

v1.0.0 (Current)

• Initial release
• Core lending functionality
• Privacy features
• Sapphire Network integration

Upcoming

• Governance token
• Yield farming
• Cross-chain bridges
• Advanced analytics

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⚠️ Disclaimer: This software is provided "as is" without warranty. Use at your own risk. This is experimental software and should not be used with real funds without thorough testing.