Managing Security Levels in a Cognitive Radio Network

Abstract

The open network architecture commonly envisioned for cognitive radio networks (CRNs), while offering flexibility, increases vulnerability from a security standpoint. Therefore, understanding and managing the trade-off between CRN performance and secu- rity is critical for practical operation. In this paper, we attempt to design a secure CRN by optimizing the total throughput performance subject to constraints on expected security level. We employ block cipher as the security mechanism, vulnerability level as the security metric, and consider an exponential adversary attack model. In order to balance physical layer security and throughput in CRNs, we propose a security level adjustment (SLA) algorithm based on the idea of water-filling. The SLA algorithm can distribute the optimal security levels as well as the optimal cipher block length for each communication link in the CRN depending on the corresponding channel quality. Simulation results for throughput show that our SLA algorithm outperforms conventional fixed block length cipher. Keywords-Cognitive Radio Networks; Physical Layer Security; Encryption; Optimization.