On the Secrecy Evaluation of a Reconfigurable Intelligent Surfaces-Aided Terahertz Network

Reconfigurable intelligent surfaces (RIS) tech-nology has shown great potential in achieving inherently secure transmissions due to its beamsteering capabilities, particularly at higher frequency bands, e.g., Terahertz (THz). However, such a communication band is impaired by atmospheric attenuation and molecular absorption, in addition to free-space path loss and small-scale fading. In this paper, a secrecy performance analysis of a RIS-aided THz wireless communication system is carried out. The considered system consists of a legitimate transmission between a pair of nodes, assisted by a RIS for enhanced communication, under the presence of a malicious eaves-dropper. Furthermore, the RIS phase shifts are assumed to be subject to phase quantization errors. An approximate secrecy outage probability (SOP) expression is computed for the considered system in terms of the key system and channel parameters. Indicative results show that the system's secrecy is slightly affected by rainy conditions, particularly in strong eavesdropping cases, while fog den-sity impacts the transmission's secrecy, particularly at higher carrier frequency values.