This thesis considers primary user emulation attacks (PUEA) in cognitive radio networks operating in the white spaces of the digital TV (DTV) band. We propose a reliable AES-assisted DTV scheme, in which an AES-encrypted reference signal is generated at the TV transmitter and used as the sync bits of the DTV data frames. By allowing a shared secret between the transmitter and the receiver, the reference signal can be regenerated at the receiver and used to achieve accurate identification of the authorized primary users. Moreover, when combined with the analysis on the auto-correlation of the received signal, the presence of the malicious user can be detected accurately no matter the primary user is present or not. We analyze the effectiveness of the proposed approach through both theoretical analysis and simulation examples. It is shown that with the AES-assisted DTV scheme, the primary user, as well as malicious user, can be detected with high accuracy under primary user emulation attacks. It should be emphasized that the proposed scheme requires no changes in hardware or system structure except of a plug-in AES chip. Potentially, it can be applied directly to today's DTV system under primary user emulation attacks for more efficient spectrum sharing.
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