Threat on Physical Layer Security: Side Channel vs. Wiretap Channel

The location-specific channel state information can be exploited to generate secret keys for wireless system services, In the multipath wireless environment. Its secrecy capacity was usually studied with the wiretap channel model. This paper proposes a side channel model which is even more threatening to the security of the physical layer randomness based secret keys. We present the information-theoretic analysis of the side channel model, and compare it with the wire-tap model. The analysis indicates that the secret key capacity of the side-channel will be lower than that of the wire-tap channel, especially with a fading scenario. We conduct MATLAB simulation of physical layer randomness based key generation and SPICE simulation of key extraction to observe the side channel leakage of the circuit. The simulation results confirm the consistency of the key bits, thus verifying the feasibility of our proposed side-channel attack scheme against the physical layer security.