11-11-2014, 10:34 AM
Abstracts: Mobile Ad Hoc Network (MANET) is a multi-hop wireless network of mobile nodes, forming a temporary network without the aid of any established infrastructure or centralized administration. Due to the absence of any dedicated routers, every node requires to contribute towards the configuration and maintenance of the routing framework. Since there are no centrally administered secure routers, attackers can easily exploit the network. Moreover, open peer-to-peer architecture, shared wireless medium, dynamic topology also adds on to the challenges in the security design of Mobile Ad Hoc Networks. These constrain make traditional secured routing schemes meant for wired networks unsuitable for mobile ad hoc environment. Routing in MANET is a challenging task receiving great amount of attention from researchers. Ad-hoc On-demand Distance Vector (AODV) is one the widely used routing protocols that is currently undergoing extensive research and development. In this paper we present the AODV protocol and survey various security enhancements that have been proposed for AODV by different researchers. We design and formulate a novel trust-based routing protocol for secure transactions, such as military and disaster relief operations, in mobile ad hoc networks (MANETs). The innovative approach is employing the idea of a trust model in the network layer of MANET so as to achieve security in mobile ad hoc networks cost-effectively. A salient feature of this approach is that, by establishing formal trust relationships among nodes, computation-intensive digital signature authorization and verification are not required for most of the secure transactions in the MANET, and hence the computation cost of the whole network can be considerably reduced. Specifically, in our trust model, trust among nodes is represented by opinion, a term derived from the subjective logic. The values of opinions are updated during a routing information exchange process. If a node performs healthy behaviors, its credibility from the viewpoints of other nodes is increased; otherwise, the credibility will be decreased, and this node will be eventually denied by the whole network. We also devise an effective recommendation mechanism to exchange the trust information among nodes. The performance of our protocol is evaluated through analyses and simulations. The results demonstrate that the whole MANET system can be maintained at a satisfactory security level with reasonable short convergence time and significant lower computation overheads. More importantly, the security level can be easily customized to meet the diverse demands from applications over ad hoc networks.