Research On Intrusion Detection And Reseponse In Mobile Ad Hoc Networks

Mobile Ad hoc networks is wildly used in the military and disaster first aid and civilian communication as it's flexibility and mobility and self-organization. But so far the protocols and standards for the Ad hoc networks were drafted under the precondition of the networks haven't attackers, Which made some hidden troubles for the realistic application, so improving the security of the Ad Hoc networks is imperative and necessary.The thesis studied the documents about the security of Ad hoc networks, specially researched on the security routing protocols and reputation mechanism which used to improve the security and the intrusion detection. At present, most of the scholars' schemes can improve the performance of the existing attacker networks, but there still are some shortages, such as adding new mechanism increased the burden of networks or took new defects in protocols. Taking these problems the thesis takes deep research on the security structure of the networks layer and the intrusion detection for routing protocols.The major duty of the Ad hoc's networks layer is to emerge routing messages and forward the routing messages and data packets, in the progress, modifying the messages by any way will make the communication mistakes or failure, so in order to guarantee the success of communication we need to defense the attacker's breakage effectively. Now there are two kind of defense way, active defense and passive defense, if we just use one of them, it can't be effective to make the attacker away from the networks. The thesis combined the both of defense means to form a security framework for networks layer, that combined the security routing protocols, neighbor nodes monitoring, intrusion detections and intrusion response, the four module cooperation to defense the intrusion.We need to build reputation mechanism in nodes to detection the intrusion in the Ad Hoc networks that the node is independent and self-organization. But the reputation judgments need consult some more factors of nodes, adding or subtracting and weighted average for these factors is not in line with the conditions of networks. So in the thesis, it proposed to use the fuzzy comprehensive evaluation to the reputation mechanism that can get appropriate trust state. In this mechanism, the performance of a node is divided into six factors, when there are communication the neighbor nodes listen and record the value of the factors, and use the comprehensive evaluation to evaluate these factors, the result of the evaluation is the reputation of a node that is used to measure whether the node can be trusted or not. And the simulation result proved this way can improve the performance of the networks, and have good effect for intrusion detection.