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HD Wallet with Passkey Authentication

A hierarchical deterministic (HD) wallet implementation with passkey authentication, supporting Ethereum and ERC20 tokens on the Sepolia network.

Table of Contents

• Features
• Project Structure
• Prerequisites
• Installation
• Configuration
• Running the Project
• API Documentation
• Frontend Documentation

Features

• BIP32 Hierarchical Deterministic Wallet implementation
• BIP39 Mnemonic code generation
• Passkey authentication for enhanced security
• Multiple account derivation
• ETH and ERC20 token support
• Sepolia testnet integration
• Modern React frontend with shadcn/ui components

Project Structure

hd-wallet/
├── backend/
│   ├── src/
│   │   ├── main.rs          # API server implementation
│   │   ├── wallet.rs        # Core wallet implementation
│   │   └── erc20_abi.json   # ERC20 contract ABI
│   ├── Cargo.toml
│   └── .env
├── frontend/
│   ├── src/
│   │   ├── app/
│   │   │   └── page.tsx     # Main page component
│   │   ├── components/
│   │   │   └── WalletDashboard.tsx
│   │   └── lib/
│   ├── package.json
│   └── .env.local
└── README.md

Prerequisites

• Rust 1.70 or higher
• Node.js 18 or higher
• npm or yarn
• An Infura account for Sepolia testnet access

Installation

1. Clone the repository:

git clone 
cd hd-wallet

2. Install backend dependencies:

cd backend
cargo build

3. Install frontend dependencies:

cd frontend
npm install

Configuration

1. Backend Configuration (.env):

RUST_LOG=debug
SERVER_PORT=8080
INFURA_PROJECT_ID=your_infura_project_id
INFURA_PROJECT_SECRET=your_infura_project_secret

2. Frontend Configuration (.env.local):

NEXT_PUBLIC_API_URL=http://localhost:8080
NEXT_PUBLIC_INFURA_PROJECT_ID=your_infura_project_id

Running the Project

1. Start the backend server:

cd backend
cargo run

2. Start the frontend development server:

cd frontend
npm run dev

The application will be available at http://localhost:3000

API Documentation

Endpoints

POST /wallet/create

Creates a new HD wallet with passkey authentication.

Request body:

{
  "passkey": "string"
}

POST /wallet/derive

Derives a new account from the HD wallet.

POST /wallet/send

Sends ETH or ERC20 tokens.

Request body:

{
  "from_index": 0,
  "to": "0x...",
  "amount": "1.0",
  "token_address": "0x..." // optional, for ERC20 transfers
}

GET /wallet/balances

Retrieves all account balances.

Frontend Documentation

Component Structure

• WalletDashboard: Main component handling wallet functionality
• Tabs:
  • Accounts: Displays derived accounts and balances
  • Send: Interface for sending transactions

Features

1. Wallet Creation:

   • Click "Create Wallet" button
   • Complete passkey registration
   • Wallet is created and stored securely

2. Account Management:

   • View all derived accounts
   • Add new accounts
   • View ETH and token balances

3. Sending Transactions:

   • Select source account
   • Choose token (ETH or ERC20)
   • Enter recipient address
   • Specify amount
   • Confirm transaction

Styling

The project uses:

• Tailwind CSS for utility-first styling
• shadcn/ui for component library
• Lucide icons for iconography

Security Considerations

1. Passkey Authentication:

   • Uses WebAuthn standard
   • Keys never leave the user's device
   • Resistant to phishing attacks

2. Private Key Security:

   • Private keys are derived on-demand
   • Never stored in plaintext
   • Protected by hardware security when available

3. Transaction Security:

   • All transactions require explicit user confirmation
   • Support for hardware wallet integration (future feature)

Development Guidelines

1. Code Style:

   • Follow Rust formatting guidelines
   • Use ESLint for TypeScript/React code
   • Document all public functions and types

2. Testing:

   • Write unit tests for all Rust functions
   • Include integration tests for API endpoints
   • Test frontend components with React Testing Library

3. Pull Requests:

   • Include detailed description
   • Add tests for new features
   • Update documentation as needed

Troubleshooting

Common issues and solutions:

1. Connection Issues:

   • Verify Infura API credentials
   • Check network connectivity
   • Ensure correct network (Sepolia) is selected

2. Transaction Failures:

   • Verify sufficient balance
   • Check gas price and limits
   • Confirm network congestion

3. Passkey Issues:

   • Ensure browser supports WebAuthn
   • Check device compatibility
   • Verify correct origin settings

Contributing

1. Fork the repository
2. Create a feature branch
3. Commit your changes
4. Push to the branch
5. Create a Pull Request

License

This project is licensed under the MIT License.