A Secure Enhanced NonCooperative Cognitive Division Multiple Access for VehicletoVehicle Communication The growth of the Internet has led to the increasing usage of smart infotainment applications on the vehicular adhoc network (VANET). Preserving privacy and security regarding the provision of smart infotainment applications while on the go is most desired. Thus, a secure authentication scheme is required. Many privacypreserving security schemes have been developed in recent times using cryptography approaches. However, these incur key management and communication overhead. The usage of thirdparty servers incurs the overhead of key computation, storage and distribution. Post completion of the initialization phase, the message is secured using cryptography and is shared among vehicles. The design of the proposed secure enhanced noncooperative cognitive division multiple access (    S xe2x88x92 ENCCMA    ) aims to eliminate the need for the local message available with the parties to be released for provisioning secure safetyrelated applications. To overcome the research challenges, this work presents a novel security scheme, namely secure noncooperative cognitive medium access (    S xe2x88x92 ENCCMA    ). The experiment is conducted to evaluate the overhead incurred in provisioning security to      ENCCMA     . The outcome shows that the overhead incurred by     S xe2x88x92 ENCCMA     over     ENCCMA     was negligible to provide the realtime security requirements of smart infotainment applications, which is experimentally shown in this paper in terms of throughput, collision and successful packet transmission considering varied environmental models such as cities, highways and rural areas.

Secrecy Outage Probability of a NOMA Scheme and Impact Imperfect Channel State Information in Underlay Cooperative Cognitive Networks Security performance and the impact of imperfect channel state information (CSI) in underlay cooperative cognitive networks (UCCN) is investigated in this paper. In the proposed scheme, relay R uses nonorthogonal multiple access (NOMA) technology to transfer messages     e 1    ,     e 2     from the source node S to User 1 (U     1    ) and User 2 (U     2    ), respectively. An eavesdropper (E) is also proposed to wiretap the messages of     U 1     and U     2    . The transmissionxe2x80x99s security performance in the proposed system was analyzed and performed over Rayleigh fading channels. Through numerical analysis, the results showed that the proposed systemxe2x80x99s secrecy performance became more efficient when the eavesdropper node E was farther away from the source node S and the intermediate cooperative relay R. The secrecy performance of U     1     was also compared to the secrecy performance of U     2    . Finally, the simulation results matched the Monte Carlo simulations well.