IoT Security Project

Efficient Methods for Securing IoT Devices Against Cyberattacks

This project implements a lightweight and secure communication system for IoT devices using encryption and authentication.

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Features

• ChaCha20 encryption (confidentiality)
• HMAC-SHA256 authentication (integrity)
• MQTT communication protocol
• Protection against tampered or fake messages

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Architecture

IoT Device (Sender) → MQTT Broker → Receiver

• Sender encrypts and signs data
• Receiver verifies and decrypts
• Invalid messages are rejected

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Testing

Test Case	Result
Valid message	✅ Accepted
Tampered message	❌ Rejected
Fake HMAC	❌ Rejected

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▶ How to Run

Install Dependencies

Make sure Python is installed, then run:

pip install -r requirements.txt

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Run the Receiver (Listener)

Open a terminal and start the receiver:

python iot_receiver.py

You should see: 📡 Listening...

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Run the Sender (IoT Device)

Open a second terminal and run:

python iot_device.py

You will see encrypted messages being sent: 📡 Sent: <encrypted_data>|

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Observe Secure Communication

In the receiver terminal, you should see:

✅ Decrypted: Temperature: 22C

This confirms that:

• Data is encrypted before transmission
• Message integrity is verified using HMAC

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Simulate an Attack (Optional)

Open a third terminal and run:

python attacker.py

The receiver will reject the fake message:

🚨 Tampered or fake message rejected!

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What This Demonstrates

• Secure communication using lightweight encryption (ChaCha20)
• Message integrity verification with HMAC-SHA256
• Protection against tampering and unauthorized message injection

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Notes

• Uses a public MQTT broker: test.mosquitto.org
• Internet connection is required
• Run sender and receiver at the same time for proper operation