Research On Secure Routing Protocols In Mobile Ad Hoc Networks

Recently, as advances in capability of mobility, wireless communication and storage of portable devices such as laptop computers, palmtop computers, mobile ad hoc networks (MANETs) have got wide and deep application, especially in military fields. Since the openness of wireless links and the particularity of military application, secure routing in MANETs is much more important.MANETs are a kind of multi-hop wireless networks without centralized administration, in which nodes perform routing discovery and routing maintenance in a self-organized way. According the scale of different networks, MANETs have two kinds of structure: flat structure and hierarchy structure. Routing protocols in MANETs have some special requirements, such as distributed operation, loop freedom, sleep period operation, unidirectional link support, etc. There are mainly two types of MANETs routing protocols: table-driven routing protocols and on-demand routing protocols, and the later is more suitable for MANETs.Due to some of its characteristics such as the absence of infrastructure, frequent changes in network topology, openness of wireless links, no way to detect and isolate misbehaving nodes, and lack of self-stabilization property, MANETs are prone to be unstable and vulnerable. Possible attacks in MANETs routing protocols are modification, impersonation and fabrication, etc. Consequently, their security issues become more urgent requirements and it is more difficult to design and implement security solutions for MANETs than for wired networks. Trusted Routing Protocol (TRP) is a trust model based routing protocol for secure MANETs, which extends the widely used AODV (Ad hoc On-demand Distance Vector) routing protocol and employs the idea of a trust model to protect routing behaviors in the network layer of MANETs. In the TRP, trust among nodes is represented by opinion, which is an item derived from subjective logic. The opinions are dynamic and updated frequently as the protocol specification. A trust recommendation mechanism is also designed to exchange trust information among nodes. Thus, a node can make objective judgment about another node's trustworthiness to maintain the whole system at a certain security level. The salient feature of TRP is that using trust relationships among nodes, there is no need for a node to request and verify certificates all the time. This greatly reduces the computation overheads. Security Association Routing Protocol (SARP) can be applied as an extension of DSR (Dynamic Source Routing) in a natural way. The proposed scheme needs the existence of a security association (SA) between the node initiating the query and the sought destination, which can be established by IKE (Internet Key Exchange) protocol. Since DSS (Digital Signature Standard) public key signature needs too many computations of exponentiation, a new authenticated key agreement protocol named MQV is introduced into IKE identification authentication techniques, which improves the efficiency of IKE key negotiation. The features introduced by SARP require the addition of SARP Header, which is integrated into the underlying protocol header structure. SARP generates a random Query Identifier to prevent packets from replay attacks and DoS attacks, and generates MAC (Message Authentication Code) to prevent packets being tampered. The protocol responsiveness is safeguarded under different types of attacks.