Cognitive radios have been identified as a solution to the crowded spectrum issue. With the
realization of cognitive radio networks came the recognition that both new and old security
threats are relevant. The cognitive radio network is still vulnerable to many of the
denial of service, wormhole, routing, and jamming attacks that plague other wireless technologies.
In addition, the cognitive radio network is vulnerable to new attacks based on
cognitive radio innovations, such as spectrum sharing, spectrum sensing, cognitive capability,
and radio reconfigurability. The scope of this survey is to present an overview of security
threats and challenges to the cognitive radio network, especially focusing on new
solutions from 2012 and the first half of 2013. Included are prior mitigation techniques that
are adaptive to the new technology, as well as new mitigation techniques specifically targeted
at new cognitive radio vulnerabilities. The threats provided are organized according
to the protocol layer at which the attack is targeted.
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