TRUST A WARE DYNAMIC SOURCE ROUTING PROTOCOL FOR AD HOC NETWORKS

The inherent properties of ad hoc networks make them vulnerable to security threats that arise from dynamic topology, open medium of communication. and the lack of conventional identification and authentication techniques. Network nodes are cooperative in nature and hence can be easily misguided by internal malicious nodes which can launch various types of attacks. Although security issues in ad hoc neru:orks have drawn considerable attention over the pastfew years, little work has been done to secure the network against internal malicious attacks. Encryption techniques can not prevent these types of attack, since once a node is compromised and under adversarial control, all the cryptographic materials are available to the attacker. These attacks are very serious and difficult to detect as they arise from trusted nodes. Thus new security mechanism is needed to provide effective solution against such attacks. Routing protocols always tend to find the shortest path between source and destination irrespective of the presence of malicious nodes in between. To overcome this problem, this paper proposes a trust aware routing protocol to secure network against internal attack, by building a trust relationship among nodes, confining the interactions to direct neighbors. The nodes evaluate the trustworthiness of their neighbors by monitoring the packet forwarding activities and by receiving reputation reports from them. The proposed protocol is integrated with DSR to identify and isolate malicious nodes. The performance of the defenseless DSR and the trusted DSR are analyzed through simulation and compared when varying the number of malicious nodes. Through simulations. it has been found that the performance of the trusted routing protocol is significantly improved compared with the defenseless routing protocol.