He received his PhD from the University of Maryland, College Park in 1993. His research interests are in ad hoc and sensor networks, network security and performance evaluation of computer systems. In recent years, he has worked extensively on security mechanisms and protocols for ad hoc and sensor networks. He was the founder of the ACM Workshop on Security in Ad hoc and Sensor Networks (SASN) and served as its co-organizer 2003 and 2004. His research has been funded by NSF, NASA and DARPA.