A secure, decentralized system for managing academic question papers using blockchain technology, ensuring integrity, traceability, and role-based access control.
- Secure Upload: Encrypted question paper storage with IPFS integration
- Role-Based Access: Admin, Moderator, Examiner, and Student roles with specific permissions
- Approval Workflow: Moderator review and approval process for all papers
- Audit Trail: Immutable blockchain logging of all system activities
- Search & Filter: Advanced filtering by subject, difficulty, status, and more
- AI-Assisted Paper Generation: Gemini-powered solution schemes and mixed question papers for different difficulty levels
- Student Chatbot: “Clear Doubts” academic assistant for conceptual queries with persistent conversation history
- End-to-End Encryption: Files encrypted before leaving the browser
- Blockchain Integrity: Smart contract verification for all operations
- Access Control: Granular permissions based on user roles
- Immutable Logs: All activities recorded permanently on blockchain
- Secure PDF Viewer: Custom viewer with watermarking, and disabled download/print for student access
Frontend (React) → Backend (Node.js/Express) → Blockchain (Ethereum)
↓ ↓
Encryption Smart Contracts
↓ ↓
IPFS Storage Metadata & Logs
- Ethereum with Solidity smart contracts
- Hardhat for development and testing
- Ganache for local blockchain
- Web3.js for blockchain interaction
- Node.js with Express.js
- MongoDB for off-chain metadata
- JWT for authentication
- Multer for file handling
- Crypto-js for encryption
- Google Gemini (via
@google/generative-ai) for solution schemes, paper generation, and chatbot
- React.js with Material-UI
- Axios for API communication
- React Router for navigation
- PDF.js-based secure viewer with watermarking and restricted actions
- Node.js (v16 or higher)
- MongoDB
- Ganache or local Ethereum node
- Git
git clone <repository-url>cd blockchain-question-paper-security# Install backend dependencies
npm install
# Install frontend dependenciescd client
npm install
cd ..# Copy environment template
cp .env.example .env
# Edit .env with your configuration# Update MongoDB URI, JWT secret, etc.# On Windows
net start MongoDB
# On macOS/Linux
sudo systemctl start mongod- Open Ganache GUI and create a new workspace
- Or use Ganache CLI:
ganache-cli
npm run compile
npm run deployAfter deploying the smart contract, you need to create an initial admin user:
# Create initial admin user in MongoDB
curl -X POST http://localhost:5000/api/init-adminThis creates an admin user with credentials:
- Email: admin@system.com
- Password: admin123
After creating the initial admin user, you need to register them in the blockchain:
# Login to get authentication token
curl -X POST http://localhost:5000/api/login \
-H "Content-Type: application/json" \
-d '{"email":"admin@system.com","password":"admin123"}'# Use the token from the response to register the user in blockchain
curl -X POST http://localhost:5000/api/register-existing \
-H "Content-Type: application/json" \
-H "Authorization: Bearer YOUR_JWT_TOKEN" \
-d '{"address":"0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266","name":"System Admin","email":"admin@system.com","role":"Admin"}'# Terminal 1 – Start blockchain (Ganache)
ganache --port 7545 --accounts 10 --mnemonic "test test test test test test test test test test test junk"# Terminal 2 – Deploy contracts (after Ganache is running)
npm run deploy
# Terminal 3 – Backend API
npm run dev
# Terminal 4 – Frontend
npm run client- Frontend: http://localhost:3000
- Backend API: http://localhost:5000
After contract deployment and following the setup steps above, you can log in with:
- Email: admin@system.com
- Password: admin123
All users must be registered in both MongoDB and the blockchain:
- Create users in MongoDB through the admin interface or API
- Register users in the blockchain using the admin panel or
/api/register-existingendpoint
- Full system access
- User management (create, activate, deactivate)
- Upload question papers
- View all papers and audit logs
- Review and approve/reject papers
- View audit logs
- Download approved papers
- Upload question papers
- Download approved papers
- View and download approved papers only
npm run testUse the provided Postman collection or test endpoints manually:
# Health check
curl http://localhost:5000/api/health
# Login (after creating users)
curl -X POST http://localhost:5000/api/login \
-H "Content-Type: application/json" \
-d '{"email":"user@example.com","password":"password"}'├── contracts/ # Solidity smart contracts
│ └── QuestionPaperSecurity.sol
├── scripts/ # Deployment scripts
│ └── deploy.js
├── test/ # Smart contract tests
│ └── QuestionPaperSecurity.test.js
├── client/ # React frontend
│ ├── src/
│ │ ├── components/ # React components
│ │ ├── contexts/ # React contexts
│ │ └── App.js
│ └── package.json
├── server.js # Express backend server
├── hardhat.config.js # Hardhat configuration
├── package.json # Backend dependencies
└── README.md
- File Encryption: AES encryption before IPFS storage
- Access Control: Smart contract role-based permissions
- Input Validation: Server-side validation for all inputs
- JWT Authentication: Secure session management
- Audit Logging: Immutable activity tracking
- Use HTTPS in production
- Implement rate limiting
- Add input sanitization
- Use environment-specific configurations
- Regular security audits
Follow the installation steps above.
- Set production environment variables
- Use PM2 for process management
- Configure reverse proxy (Nginx)
- Set up SSL certificates
cd client
npm run build
# Deploy build folder to web server- Deploy to testnet (Ropsten, Goerli)
- Update contract addresses in configuration
- For mainnet: Comprehensive security audit required
POST /api/login- User loginPOST /api/register- Register new user (Admin only)GET /api/profile- Get user profile
POST /api/upload- Upload question paperGET /api/papers- Get all papers (filtered by role)POST /api/papers/:id/approve- Approve paper (Moderator)POST /api/papers/:id/reject- Reject paper (Moderator)GET /api/papers/:id/download- Download paper
GET /api/health- System health checkGET /api/audit-logs- Get audit logs (Admin/Moderator)
- Ensure Ganache is running
- Check network configuration in hardhat.config.js
- Verify sufficient ETH in deployer account
- Verify MongoDB is running
- Check connection string in .env
- Ensure database permissions
- Clear node_modules and reinstall
- Check Node.js version compatibility
- Verify all dependencies are installed
This error occurs when a user exists in MongoDB but is not registered in the blockchain. To fix:
- Ensure the user is registered in the blockchain using the admin panel or API
- The user's address must match between MongoDB and blockchain
If you're getting this generic error:
- Check that the user is properly registered in both MongoDB and blockchain
- Verify that Ganache is running and accessible
- Check the server logs for more detailed error information
- IPFS Integration: Full decentralized storage
- Multi-signature Approval: Multiple moderator approval
- Paper Versioning: Track paper revisions
- Notification System: Email/SMS notifications
- Analytics Dashboard: Usage statistics and insights
- Mobile App: React Native mobile application
- Layer 2 Solutions: Polygon/Arbitrum integration
- Microservices: Service decomposition
- Caching: Redis implementation
- CDN: Content delivery optimization
This project is licensed under the MIT License - see the LICENSE file for details.
- Fork the repository
- Create a feature branch
- Commit your changes
- Push to the branch
- Create a Pull Request
For support and questions:
- Create an issue in the repository
- Contact the development team
- Check the troubleshooting section
- Ethereum Foundation for blockchain technology
- OpenZeppelin for smart contract security patterns
- React team for the frontend framework
- All contributors and testers