Securing cooperative spectrum sensing against ISSDF attack using dynamic trust evaluation in cognitive radio networks

Cooperative spectrum sensing CSS for vacant spectrum is one of the key techniques in cognitive radio networks. However, most of CSS schemes assume secondary users SUs to always tell the truth, and thus offering opportunities for malicious SUs to launch the spectrum-sensing data falsification attack SSDF attack. To combat such vicious behaviors, recent efforts have been made to trust evaluation. In this paper, we argue that powering CSS with traditional trust schemes is not enough. The intermittent SSDF attack ISSDF attack is found in this paper. Unlike SSDF, ISSDF attackers can maintain high trustworthiness in an alternant process of reporting true or false sensing data, resulting in difficultly detecting malicious SUs in trust schemes. To defend against ISSDF attack for CSS, a novel-trust scheme using dynamic evaluation is proposed in this paper. Simulation results show that this scheme can successfully reduce the power of ISSDF and thus can ensure the performance of CSS.