Research On Secure Routing Protocols For MANET

The Mobile Ad Hoc networks is a self-organized network composed of mobile host with wireless equipments . Unlike traditional mobile wireless networks, ad hoc networks do not rely on any fixed infrastructure and are managed by distributed way, all hosts act as routers and communicate through multi-hop routing,the Ad Hoc networks is a self-created,self-organized and self-managed networks.Ad hoc networks are a new paradigm of wireless communication for mobile nodes. In an ad hoc network, there is no fixed infrastructure such as base stations or mobile switching centers. Mobile nodes that are within each other's radio range communicate directly via wireless links, while those that are far apart rely on other nodes to relay messages as routers. Because of self-organization, dynamic topology and openness of wireless links, ad hoc networks suffer more attacks than conventional networks. Especially, as one of the core functions, the routing protocols' security takes very important part.Compared with the commom mobile networks and fixed networks, the Ad Hoc networks is more possibly to be attacked because the wireless channel is open, the hostile behavior is difficult to detect and the Ad Hoc network is dynamic,so the secure routing protocol is very important for the Ad Hoc networks. The main contributions are as follows:Aiming at the characteristics of Ad Hoc networks, a distributed CA solution is proposed,which is composed of the initializing processing, user certificates updating and the private key updating and indicates that pure threshold cryptography have the application problem in practice. By introducing a prime field into the solution,the practicability is improved.The self-organized public key management framework is discussed, a fully self-organized public-key management based on absolute trust model without any centralized authority is proposed ,which allows users to generate their public-private key pairs, to issue certificates, and the trust relation spreads rationally according to the truly human relations. In contrast with the traditional self-Organized Public-Key Management, the average certificates paths get more short,the authentication pass rates gets more high and the most important is that the absolute based model fits the trust requirement of each host better.A bridge nodes based secure link state routing scheme-BSOLSR is proposed to solve the asymmetrical link problem. At first the security problems in OLSR are analysed, a secure SOLSR framework is built, neighbour authenticating protocol, verifying mechanism and trust evaluating is introduced to enhance the OLSR security. The existing secure routing protocols are mainly based on bi-directional and symmetrical links, however, because of the special digital signals transmission equipments, which have different physical characteristic such as power range, there are many asymmetrical links in true wireless networks, so the successful authentication ratio is limited, even they can't work in some extreme circumstance. This paper proposes a bridge nodes based secure link state routing scheme-BSOLSR to solve the asymmetrical link problem. The simulation presents that the successful authentication ratio is enhanced and the average length of routing paths is more short than that of SOLSR, which is important to the communication efficiency and networks performance.Moving characteristic is a important factor in secure routing for Ad Hoc networks. Most secure routing protocols are difficult to finish the authenticating processing and can't build the secure routing in a mutative and high speed moving network because authenticating is a continuous processing for messages exchanging and the moving characteristic can't ensure the continuity. This paper proposes the trust preserving based secure routing protocol based on OLSR, the trust preserving method is adopted to accomplish the authenticating and resolve the high speed moving authenticating problem, which is proved with the formal language. Aiming at the low flexibility of most trust evaluating system, a novely evaluating system is proposed, by which the nodes get the trust information, identify and limit the vicious nodes, at the same time, it can resist the associated attacks,such as worm-hole attack. The simulations shows that in a high speed moving network, The TPSRP's authenticating performance is more better than that of the traditional and can isolate the attacking nodes effectively.Anonymous and controllable routing is a important problem on Ad Hoc routing security. The controllable routing is not considered in current Ad Hoc anonymous routing, however, which is a effect way to improve the routing security and the bandwidth usage ratio. SPKI certificates have anonymity characteristics. In this paper, this kind of certificates are introduced into Ad Hoc Anonymous routing, the anonymity is not impaired, as result, the controllability and security performance about routing are improved.