ABSTRACT
This chapter provides an overview of the security problem in cognitive radio networks (CRNs). It discusses trust as the metric used to determine if users in the network are good or bad. The chapter examines three types of threats. The first threat is route-disrupting attacks. Route diversity can protect against route-disrupting attacks. Honesty, adaptivity, diversity, observer, and friendship technique is described as a good defense mechanism against these attacks. The second threat is jamming attacks. Jamming attacks occur when multiple malicious users try to interrupt the communications of secondary users (SUs), by injecting interference into their signal. The third threat concerns primary user emulation (PUE) attacks. In PUE attacks, the attackers only transmit in idle bands, as the malicious users need to avoid interfering with legitimate primary users (PUs). Therefore, the malicious attacker prevents other SUs from using that band by emulating the signal characteristics of a legitimate PU.
