Deploying multi-hop wireless ad hoc networks in mission critical operations will potentially improve the effectiveness and reduce the cost of these operations. In such environments, the availability of ad hoc networks will be utmost important.

In this paper, we devise mechanisms that can strengthen the resilience of an ad hoc network against attacks, failures, accidents, and selfishness. The adversary is an insider that controls an unknown subset of the nodes or routers. Our objective is to prevent the adversary from interfering with the "healthy" portion of the network. In this direction, we advocate the use of a tool, called Byzantine detection, to identify the adversarial locations at a fine granularity so that these locations can be subsequently bypassed. Our main contribution is a Byzantine detection protocol that achieves a significant reduction in the per-packet computational and communication overhead.