Final Year Project: Decentralized Online Banking (Backend)

This repository contains the backend services for a modern, blockchain-integrated banking platform. It serves as the high-performance bridge between the traditional client interface (Cyter) and the decentralized ledger (Ethereum Smart Contracts).

🏗️ Project Architecture

backend/
├── config/            # Database connection and environment setup
├── controllers/       # Business logic and request handlers
├── middleware/        # Authentication, validation, and error handling
├── models/            # Mongoose schemas (User, Account, etc.)
├── routes/            # API route definitions
├── services/          # Core logic for banking operations
└── server.ts          # Application entry point (Fastify/Express)

🚀 Key Features

• User Management: Secure registration, login, and profile management.
• Blockchain Integration: Connects to Ethereum (Sepolia) via Web3.js.
• Banking Operations:
  • Wallets: Create and manage crypto wallets.
  • Transfers: Peer-to-peer (P2P) token transfers.
  • Bridge: Deposit/Withdrawal functions for interacting with smart contracts.
• Real-time Notifications: Socket.IO for live updates on transaction status.
• Scalability:
  • Fastify framework for high-performance routing.
  • Redis/BullMQ for background job processing and queue management.
• Data Layer:
  • PostgreSQL database for off-chain data.
  • Prisma ORM for type-safe database interactions.

🔧 Setup & Installation

Prerequisites

• Node.js (v14+ recommended)
• PostgreSQL (Local or Remote)
• Redis (Local or Remote)
• npm or yarn

1. Install Dependencies

npm install
# or
yarn install

2. Database Configuration

Create a .env file in the backend/ directory with the following variables:

# Server Port
PORT=9001
NODE_ENV=development

# PostgreSQL
DATABASE_URL=postgresql://user:password@localhost:5432/bank_db

# Redis
REDIS_URL=redis://localhost:6379

# JWT
JWT_SECRET=your_jwt_secret
JWT_EXPIRE=1d

# CORS
CORS_ORIGINS=http://localhost:5173,http://localhost:3000

# Ethereum (Smart Contract)
ETH_RPC_URL=https://eth-sepolia.g.alchemy.com/v2/your_alchemy_key
ETH_PRIVATE_KEY=your_private_key
ETH_DBANK_CONTRACT_ADDRESS=0x...
ETH_ACCOUNT_CONTRACT_ADDRESS=0x...

3. Database Migration

Run the Prisma migrations to create the necessary tables:

npx prisma migrate dev --name init

4. Seed the Database

Run the seed script to create initial data (e.g., admin user):

npx tsx prisma/seed.ts

5. Start the Server

npm run dev
# or
yarn dev

The server will start on http://localhost:9001.

📋 API Endpoints

The following API endpoints are available (prefixed with /api or no prefix):

🔐 Auth

• POST /auth/register - Register a new user.
• POST /auth/login - Login and get JWT token.
• POST /auth/logout - Logout user.
• POST /auth/refresh - Refresh access token.

👤 Users

• GET /users - Get all users (Admin).
• GET /users/:id - Get user by ID.
• GET /user/me - Get current user profile.
• PUT /users/:id - Update user details.

💼 Wallet

• GET /wallet/private-key - Get wallet (Admin only).
• POST /wallet/generate-random - Generate random wallet (Admin only).
• POST /wallet/generate-linked - Generate wallet linked to user.
• DELETE /wallet/delete-linked - Delete linked wallet (Admin only).

🏦 Account

• POST /account/create - Create account.
• GET /account/list - List accounts.
• GET /account/:walletAddress - Get account by wallet address.

💸 Transfer

• POST /transfer/deposit - Deposit funds.
• POST /transfer/withdraw - Withdraw funds.
• POST /transfer/p2p - Send P2P transfer.
• GET /transfer/transaction - Get transaction history.
• GET /transfer/history/:walletAddress - Get user's transaction history.

🌉 Bridge

• POST /bridge/deposit-eth - Deposit ETH to contract.
• POST /bridge/withdraw-eth - Withdraw ETH from contract.
• POST /bridge/deposit-cgn - Deposit CNGN to contract.
• POST /bridge/withdraw-cgn - Withdraw CNGN from contract.
• POST /bridge/mint - Mint CNGN tokens (Admin).
• POST /bridge/burn - Burn CNGN tokens.

📊 Ledger

• GET /ledger/balance/:walletAddress - Get wallet balance.
• GET /ledger/cgn-balance/:walletAddress - Get CNGN token balance.
• GET /ledger/supply - Get total token supply.

👥 Admin

• GET /admin/users - Get all users.
• DELETE /admin/users/:id - Delete a user.
• PUT /admin/users/:id/role - Update user role.

🧩 Smart Contracts

The frontend interacts with Ethereum smart contracts deployed on the Sepolia Testnet:

1. Account.sol: Manages account registration and state.
2. Transfer.sol: Handles business logic for deposits, withdrawals, and P2P transfers.

🛠️ Development Commands

• Run Development Server: npm run dev
• Build for Production: npm run build
• Start Production Server: npm run start
• Run Tests: npm run test (if available)
• Database Migrate: npx prisma migrate dev
• Seed Database: npx tsx prisma/seed.ts