A mobile ad-hoc network is an autonomous group of mobile users that communicate over reasonably slow wireless links. The network topology may vary rapidly over time because the nodes are mobile. The network is decentralized, where all network activity, including discovering the topology and delivering messages must be executed by the nodes themselves. Due to absence of centralized control, multi-hop communications and dynamic network topology, the provision of making routing secure in mobile ad hoc networks is much more challenging than the security in wired network or infrastructure based networks.