Timestamp-based AES Key Refresh for IoT Security

This repository contains the implementation of a lightweight timestamp-driven AES key refresh mechanism for secure data transmission in IoT environments.
The approach dynamically regenerates AES-256 keys using system timestamps, ensuring forward secrecy with negligible performance overhead.

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🔑 Abstract

Secure data transmission in IoT networks often faces challenges of key compromise and synchronization.
This work proposes a timestamp-based AES key refresh mechanism, where session keys are derived as:

$$ K_t = f(K_{master}, T) $$

• K_t → time-dependent session key
• K_master → shared master secret
• T → timestamp truncated to granularity (seconds/minutes)

Results demonstrate that:

• 10s refresh interval achieved 98.5% success with minimal latency overhead.
• Frequent refresh (5s) increases mismatch but boosts security.
• Performance overhead < 10%, making it feasible for real-time IoT use cases.
• The honeypot successfully detected 100% of replay attempts during controlled tests (10 attempts, 30s TTL).
• Bucket drift tolerance (±1) allowed for minor clock skew without false negatives.
• AES-GCM decryption overhead was <3% CPU on a standard IoT edge board (10s interval, 100 messages).

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📂 Repository Structure

├── timestamp code.ipynb # Jupyter notebook with implementation & experiments ├── requirements.txt # Python dependencies ├── results/ # Graphs & tables from experiments ├── LICENSE # Open-source license └── README.md # Project overview

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⚙️ Installation & Usage

Clone the repo and install dependencies:

git clone https://github.com/SunnYNehrA01/TimeStamp-AES-Refresh.git cd timestamp-aes-refresh pip install -r requirements.txt

Run the notebook: jupyter notebook timestamp code.ipynb

📊 Results

Simulation results (packet success vs. refresh interval):

Refresh Interval Success Rate (%) Mismatch Rate (%) Avg Latency (ms) 30s 100.0 0.0 0.08 10s 98.3 1.7 0.06 5s 95.0 5.0 0.01

Honeypot Simulation Detection Results [Key Refresh] active bucket=1757164160 (2025-09-06 18:39:20)[Honeypot] started (refresh_interval=10s, drift_buckets=±1) [Honeypot] Decrypted (kid=1757164160) mid=471bde4e5ee7e550: replay-test-payload [Demo Callback] meta: {'key_bucket': 1757164160, 'mid': '471bde4e5ee7e550'} payload preview: 7265706c61792d746573742d7061796c [Honeypot] Replay detected (mid=471bde4e5ee7e550). Discarding. [Honeypot] stopped

🔒 Security Notes

Replay attacks fail after key refresh.

Effective keyspace refreshes every interval.

Preserves AES-level security while reducing reliance on costly public-key cryptography.

📜 Citation

If you use this work, please cite:

Author: Sunny Nehra, Lakshya Soni

Title: Timestamp-based AES Key Refresh for IoT Security

Year: 2025

Repository: https://github.com/SunnYNehrA01/TimeStamp-AES-Refresh

📌 Future Work

Adaptive refresh intervals based on network load

Blockchain-based timestamp synchronization

Post-quantum key derivation integration

Hardware implementation on IoT boards (Raspberry Pi, ESP32)