Semantic Security for Indoor THz-Wireless Communication

TL;DR

This paper investigates physical-layer security in indoor THz wireless communication, analyzing secure communication scenarios and revealing trade-offs between security levels and receiver accessibility, with insights on improving security through code and antenna design.

Contribution

It provides the first analysis of semantic security guarantees for indoor THz wireless links using finite-blocklength models, highlighting security trade-offs and design directions.

Findings

Weakly directed antennas create large insecure regions.

Large distances between transmitter and receiver increase insecurity.

Secrecy code and antenna parameters significantly affect security levels.

Abstract

Physical-layer security (PLS) for industrial indoor terahertz (THz) wireless communication applications is considered. We use a similar model as being employed for additive white Gaussian noise (AWGN) wireless communication channels. A cell communication and a directed communication scenario are analyzed to illustrate the achievable semantic security guarantees for a wiretap channel with finite-blocklength THz-wireless communication links. We show that weakly directed transmitter (Alice) antennas, which allow cell-type communication with multiple legitimate receivers (Bobs) without adaptation of the alignment, result in large insecure regions. In the directed communication scenario, the resulting insecure regions are shown to cover a large volume of the indoor environment only if the distance between Alice and Bob is large. Thus, our results for the two selected scenarios reveal that there is a stringent trade-off between the targeted semantic security level and the number of reliably and securely accessible legitimate receivers. Furthermore, the effects of secrecy code parameters and antenna properties on the achievable semantic security levels are illustrated to show directions for possible improvements to guarantee practically-acceptable security levels with PLS methods for industrial indoor THz-wireless communication applications.