Countermeasures for layered security attacks on cognitive radio networks based on modified digital signature scheme

Wireless technologies and services have been witnessed a rapid growth in the past few years, due to this development, spectrum scarcity and shortage has become a major concern, several spectrum portions of the static allocated licensed bands are under-utilized, Cognitive radio networks (CRNs) the most encouraging solution in enhancing the spectrum utilization by providing licensed spectrum portions to unlicensed users, however due to nature of these networks, CRNs are exposed to different types of security threats and attacks from different malicious users, which can affect the network availability and performance, in this paper a proposed countermeasures based on authentication mechanisms and digital signature scheme introduced to provide a defend strategy from the well-known attacks that could be launched by malicious and selfish users in CRNs.