Security in mobile AD HOC networks

Security is paramount in mobile ad hoc networks (MANETs) since a MANET is neither conducive to centralized authorities nor suitable for inheriting the solutions that have been proposed for wired networks. Given that end-to-end communication between applications relies on the self-organized characteristics of MANETs, most if not all the proposed security solutions concentrate on securing communication through multi-hop trustworthy nodes. In this chapter, we present state-of-the-art security in MANETs and the survey comprises MANET-based secure routing, key management, and trust management systems. However, we confine ourselves to a few well-regarded proposals due to the exhaustive list of proposals available in each of the above-mentioned categories. First, we discuss the features inherent in MANETs and their impact on the design of security mechanisms, in addition to the threats and attacks that are common in MANETs. Second, we describe a few well-known solutions in the area of secure routing and key management to demonstrate their role as a prevention system. We then discuss the limitations of those systems such as their inability to react to dynamically changing attack patterns and their assumption that nodes will cooperate for routing and network management. Finally, we address the recent advancements in security systems, where a defense-in-depth approach is adopted to incorporate trust management systems as the second layer of defense to prevention systems. Trust management systems complement prevention systems by measuring the trustworthiness of nodes and promptly react to dynamically changing attack patterns. We then detail the limitations of trust management systems and discuss possible research directions to address those limitations.