Security Aspects in Wireless and Mobile Networks

Heesook Choi (The Pennsylvania State University)

Monday, April 2nd, 2007
10 am - SENSQ 5317

Refreshments at 9:30 a.m

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Abstract

Wireless and mobile networks play an important role in realizing the vision of ubiquitous computing. In this talk I address two important security issues in mobile ad hoc and mobile IP networks. In wireless environments, privacy concerns grow because it is easy for nodes to eavesdrop on communications. In both military and civilian applications of mobile ad hoc networks, users may find any exposure of information unacceptable. For instance, a user may not want others to know with whom (s)he is talking or where (s)he is. To address these issues, I present a Privacy Preserving Communication System (PPCS) which provides a comprehensive solution to anonymize communication end-points, keep the location and identifier of a node unlinkable, and mask the existence of communication flows. To evaluate the effectiveness of PPCS, we define the optimal guessing strategy that may be used by one or more compromised nodes in cooperation and show that with PPCS, the probability of correctly guessing the source or destination of a flow is independent of the number of compromised nodes on the path. Even with collaboration, the adversary cannot confirm that it has guessed correctly, and it cannot learn the real identifier of the source or destination.

Second, to achieve high throughput in wireless networks, smart packet processing in the access routers has been proposed to overcome the effects of the wireless interface. However, this service cannot be provided if data sessions are protected using end-to-end encryption as with IPsec. A previously proposed protocol, called Multi-layered IPsec (ML-IPsec), modifies IPsec in a way so that certain portions of the datagram may be exposed to intermediate network elements, enabling these elements to provide performance enhancements. I present Mobile Multi-Layered IPsec (MML-IPsec) in which we extend ML-IPsec to deal with mobility in Mobile IP and make it suitable for wireless networks. We define and implement an efficient key distribution protocol to enable fast ML-IPsec session initialization, and two mobility protocols that are compatible with Mobile IP and maintain ML-IPsec sessions. We find the resulting protocol greatly increases throughput, while protecting data sessions using MML-IPsec.

Biography of Speaker

Heesook Choi received her B.S. degree in Computer Science and Statistics and M.S. degree in Computer Science from the Chungnam National University, Korea, in 1990 and 1992 respectively. She was a senior research staff in Electronics and Telecommunications Research Institute (ETRI) in Korea before she enrolled in the Ph.D. program at the Pennsylvania State University in August 2002. Her research interests lie in security and privacy in distributed systems and wireless mobile networks, focusing on designing algorithms and conducting system research.