Research On Trust Evaluation Based Secure Routing Protocol In Mobile Ad Hoc Networks

Mobile Ad Hoc Network (MANET) is a special wireless network formed by a group of mobile nodes with wireless transceiver. It is self-organized by some distributed protocols. Due to the absence of infrastructure, dynamic topology, wireless communication, lack of self-stability and so on. Routing protocols in MANET, compare to those in traditional networks, are more likely to suffer some kinds of attacks and security threats.Firstly, the thesis describes several typical routing protocols of MANET, analyzes their security vulnerabilites and generalizes the security threats presented by active attacks and passive attacks. Then summarizes some typical existing secure routing protocols based on cryptography or trust model. To satisfy the security requirements of hierarchical MANET, the thesis presents a new trust evaluation model which gives the quantitative description of trust based on fuzzy set, introduces vector closeness degree for computing of the recommendation trust weights, and also discusses the transfer and synthetic calculations of trust, emphasizing the system's scalability, accuracy and robustness. Finally, the thesis presents a secure routing protocol based on the proposed trust model and CBRP protocol. In order to distinguish trusted nodes from untrusted ones, all nodes running the protocol perform the trust evaluation modules cooperately, compute the trust degree of nodes by the interaction experience and active observation, thus to guide and encourage nodes to implement normal routing operation, isolate nodes with abnormal behavior from routing. Simulation results show that the proposed routing protocol can effectively address the impact of bad nodes on the network, and has better dynamic adaptability.