📸 QR-Based Attendance System 🧑‍🎓

A secure, geolocation-verified student attendance management system using QR codes, device fingerprinting, and real-time GPS validation. Built using Node.js, MongoDB, and Tailwind CSS for modern web-based attendance tracking.

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🚀 Features

• ✅ Secure QR Code Generation (valid for 15 minutes)
• 📍 Geofencing: Marks attendance only if within 100 meters of class
• 🧠 Device Fingerprinting to prevent multiple entries
• 📅 Attendance Dashboard with analytics
• 🛡 Rate-limited QR generation to prevent abuse
• 🎨 Clean, responsive UI with Tailwind CSS
• 🧾 MongoDB-based persistent storage

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📂 Project Structure

📦 qr-attendance-system/
├── backend/
│   ├── server.js
│   ├── qr-generator.js
│   ├── models/
│   └── routes/
├── frontend/
│   ├── index.html
│   ├── qr-scanner.html
│   ├── script.js
│   └── styles/
└── README.md

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🛠 Tech Stack

Layer	Tech/Library
Frontend	HTML, TailwindCSS, JavaScript
Backend	Node.js, Express.js
Database	MongoDB (via Mongoose)
Security	Helmet.js, SHA-256 (crypto), CORS
Features	QR Code (qrcode), Geo Validation
Extras	Device FingerprintJS, Haversine Algo

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🔐 Core Algorithms

• Haversine Formula – Validates student is within campus radius
• SHA-256 Hashing – Signs QR code session payload
• Canvas Fingerprinting – Tracks device identity
• Rate Limiting – Protects QR endpoint (max 5/minute/IP)
• Session Validation – Ensures QR isn't reused or expired

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📸 How It Works

1. Admin generates a time-limited QR code via /qr-scanner.html
2. Student scans the QR → redirected to /index.html?sessionId=...
3. System captures:
   • GPS coordinates
   • Device fingerprint
   • Student details
4. Backend checks:
   • If student is near classroom
   • If attendance already marked today
   • If QR session is valid
5. Attendance is stored and can be viewed from the dashboard.

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📦 Setup Instructions

🖥 Prerequisites

• Node.js & npm
• MongoDB (local or Atlas)
• .env file with the following:

PORT=5000
MONGO_URI=mongodb://localhost:27017/attendance
QR_SECRET_KEY=supersecret123

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📁 Installation

# Clone the repo
git clone https://github.com/yourusername/qr-based-attendance-system.git
cd qr-based-attendance-system

# Install dependencies
npm install

# Start the backend server
node server.js

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🌐 Frontend Access

Open these in your browser:

• http://localhost:5000/qr-scanner.html → Generate QR code
• http://localhost:5000/index.html?sessionId=... → Mark attendance

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📊 Dashboard (Optional)

You can extend the system with a dashboard page (dashboard.html) to visualize:

• Attendance %
• Dates present
• Department vs student average

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🧪 Testing Tips

• Spoof location with browser dev tools
• Use different devices or browsers to check fingerprint tracking
• Try scanning expired QR to validate session handling

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🤝 Contributing

Pull requests are welcome! For major changes, open an issue first to discuss what you’d like to improve.

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📃 License

This project is open source and available under the MIT License.

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👩‍💻 Author

Vaishnavi Khandelwal B.Tech CSE Student | QR Attendance System Developer

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📌 Academic Relevance

This project is part of a DAA-based PBL focusing on:

• Secure Hashing (SHA-256)
• Haversine Formula (spatial validation)
• Algorithm optimization (QR reuse prevention, rate limiting)

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