Architecture Technology Corporation (ATC) has developed a new approach for building intrusion resistant ad hoc networks called TIARA (Techniques for Intrusion-Resistant Ad Hoc Routing Algorithms). The approach, developed with funding from DARPA's Fault Tolerant Networks program, relies on extending the capabilities of existing ad hoc routing algorithms to handle intruders without modifying these algorithms. TIARA implements new network layer survivability mechanisms for detecting and recovering from intruder induced malicious faults that work in concert with existing ad hoc routing algorithms and augment their capabilities. The TIARA implementation architecture is designed to allow these survivability mechanisms to be "plugged" into existing wireless routers with little effort.