Energy-Efficient Defensive Strategy Against Hybrid SSDF/Eavesdropping Attacks Over Nakagami- ${m}$ Channels

During cooperative spectrum sensing (CSS) in cognitive radio networks, malicious users (MUs) not only launch spectrum sensing data falsification (SSDF) attack, but also wiretap legitimate users (LUs) during the reporting phase. In this letter, an energy-efficient defensive strategy against hybrid SSDF/eavesdropping attacks is proposed, to achieve both energyefficiency and physical layer security. Secure CSS reporting/ eavesdropping channels are modeled as Nakagami-m fading channels. The optimal MUs and LUs are determined via the achievement of maximum energy-efficiency that is subject to the optimal report bits, report distance as well as report error rate. Furthermore, intercept performance of the proposed strategy in the presence of multiple MUs is also investigated. Simulation results reveal that, the proposed strategy is immune to MU numbers, report distance as well as report error rate. Moreover, the intercept probability can be reduced in multiple MUs scenario when the legitimate-to-malicious ratio is high and the channel fading factor ratio is large.