Physical layer security (PLS) offers a promising alternative to traditional cryptographic methods, particularly for resource-constrained devices such as IoT sensors. However, secret key generation (SKG) techniques typically rely on channel variations caused by mobility—making them less effective in low-mobility or static environments. This paper addresses this limitation by introducing a method that injects additional randomness into the system through locally generated pilot signals. Instead of relying on mobility, both communicating parties independently randomize their transmitted pilot signals, creating highly correlated observations that can be used as a shared source for secret key generation.
The approach is evaluated using real-world measurement data collected at the Nokia campus in Stuttgart. As illustrated in the results on page 3 (Fig. 2), the proposed method significantly improves both mutual information and secret key rate compared to relying solely on natural channel variations. Gains of up to 30% in mutual information and 50% in secret key rate are observed at high signal-to-noise ratios. Importantly, the method does not require multiple antennas or external helpers, making it suitable for lightweight and practical deployments. The results also show that controlled randomness introduced via pilot signals can have a stronger impact than environmental dynamics alone, particularly in low-mobility scenarios.
Overall, this work demonstrates a practical way to enable reliable secret key generation in static or low-mobility environments, paving the way for efficient and scalable security solutions in future wireless and IoT systems.
Enhancing_Secret_Key_Generation_in_Low-Mobility_Scenarios_by_Locally_Generated_Pilots