Eavesdropping Risk Evaluation on Terahertz Wireless Channels in Atmospheric Turbulence

TL;DR

This paper evaluates the eavesdropping risks of terahertz wireless channels affected by atmospheric turbulence, developing models to predict signal leakage and proposing design strategies to enhance physical layer security.

Contribution

It introduces a comprehensive physical layer model for THz channels considering turbulence effects and analyzes eavesdropping risks and mitigation strategies.

Findings

Secrecy capacity decreases with increased turbulence strength.

Signal leakage regions expand with atmospheric turbulence.

Design guidelines to minimize eavesdropping risk are proposed.

Abstract

Wireless networks operating at terahertz (THz) frequencies have been proposed as a promising candidate to support the ever-increasing capacity demand, which cannot be satisfied with existing radio-frequency (RF) technology. On the other hand, it likely will serve as backbone infrastructure and could therefore be an attractive target for eavesdropping attacks. Compared with regular RF spectrum, wireless channels in the THz range could be less vulnerable to interceptions because of their high beam directionality and small signal coverage. However, a risk for eavesdropping can still exist due to the multipath effects caused by unintended scattering. In this work, an eavesdropping risk for THz channel passing atmospheric turbulences and producing compromising emissions is investigated from a physical layer perspective. A model combining signal attenuation due to turbulence, gaseous absorption and beam divergence, is developed for prediction of deterministic and probabilistic signal leakages. The secrecy capacity and outage probability of the THz channel are derived and analyzed with respect to variations of the turbulence strength and other channels characteristics. The dependence of the channel performance on the eavesdropper's position is investigated with respect to the maximum safe data transmission rate (MSR) and the signal leakage region. Design results for THz channels are provided to minimize an eavesdropping risk at physical layer.