RIS-assisted Physical Layer Security

2025-01-30

AI Summary

This work addresses the limited physical-layer secrecy capacity in multi-eavesdropper scenarios. We propose a reconfigurable intelligent surface (RIS)-aided semantic security enhancement scheme. By modeling the RIS-assisted eavesdropping channel, we exploit the RIS to achieve spatial beam separation at the transmitter and employ an orthogonal combiner at the legitimate receiver to jointly process direct and reflected signals. For the first time under the semantic security framework, we derive the achievable secrecy rate for RIS-enabled channels and design a joint optimization algorithm to maximize the secrecy rate by co-designing the RIS phase-shift matrix and the receiver’s combining weights. Simulation results demonstrate that the proposed scheme significantly improves secrecy capacity—particularly under low signal-to-noise ratio (SNR) and in multi-eavesdropper settings—while exhibiting robustness against variations in eavesdropper count, location, and total transmit power.

Technology Category

• Intelligent Robots: Multi-Robot Systems
• Search and Optimization: Metareasoning and Metaheuristics
• Machine Learning: Semi-Supervised Learning

Application Category

• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs

Abstract

We propose a reconfigurable intelligent surface (RIS)-assisted wiretap channel, where the RIS is strategically deployed to provide a spatial separation to the transmitter, and orthogonal combiners are employed at the legitimate receiver to extract the data streams from the direct and RIS-assisted links. Then we derive the achievable secrecy rate under semantic security for the RIS-assisted channel and design an algorithm for the secrecy rate optimization problem. The simulation results show the effects of total transmit power, the location and number of eavesdroppers on the security performance.

Problem

• Reconfigurable Intelligent Surface (RIS)
• Physical Layer Security
• Multiple Eavesdroppers

Innovation

• Reconfigurable Intelligent Surfaces (RIS)
• Physical Layer Security
• Intelligent Mirror-Assisted Information Path