Secure routing in ad hoc networks and a related intrusion detection problem

The intrinsic nature of wireless ad hoc networks makes them vulnerable to various passive or active attacks. Thus, there is no guarantee that a routed communication path is free of malicious nodes that will not comply with the employed protocol and attempt to interfere the network operations. In this paper, we survey the problem of secure routing in ad hoc wireless networks, and discuss the related techniques of cryptographic key distribution. However, no matter how secure the routing protocol is, it is still possible that some nodes are compromised and become malicious. The presence of compromised nodes, especially in nodes that are communication bottlenecks, limit the effectiveness of the described secure routing protocols. We therefore consider the problem of intrusion detection for such nodes. The intrusion detection problem and some solutions are described in detail for a concrete queueing model of medium access. The extensions of the solutions to address the problem in more general scenarios are also discussed.