Opportunistic communication in MANET's reduce resource starvation and enhances the stability of a network by decreasing high routing overhead. But the frequent opportunistic contact among the devices is prone to security threats. This article proposes a novel cognitive opportunistic computing-based security scheme (COSS) to ensure secure in opportunistic network. The COSS provides multilevel security with different levels of severity. It recommends the security-collaboration-sensitivity parameter(ScS) with collaboration- sensitivity parameter for route handling. Based on the recommended ScS, the type of security scheme is derived from the database and is implemented for that transaction. The scheme involves the following processes for security: contact analysis, belief formulation and security collaboration logic. A COSS scheme is applied in a military attack scenario in which nodes are constructed as a hierarchical model with an access control for communication. Experimental results show that the scheme improves performance in terms of convergence time, energy efficiency and reliability.

In Manet's Dynamics and Robustness are the key features of the nodes and are governed by several routing protocols such as AODV, DSR and so on. However in the network the growing resource demand leads to resource scarcity. The Node Mobility often leads to the link breakages and high routing overhead decreasing the stability and reliability of the network connectivity. In this context, the paper proposes a novel opportunistic AODV routing scheme which implements a cognitive agent based intelligent technique to set up a stable connectivity over the Manet. The Scheme computes the routing metric (rf) based on the collaboration sensitivity levels of the nodes obtained based through the knowledge-based decision. This