CENS Technical Seminar Series

Improving Wireless Privacy with an Identifier-Free Link Layer Protocol

Invited Speaker: Dr. Ben Greenstein, Intel Corporation
Date: April 4, 2008
Time: 1:00 PM - 2:00 PM
Venue: Boelter Hall 4760

Abstract

In this talk, I’ll present the design of an 802.11-like wireless link layer protocol that obfuscates all transmitted bits to increase privacy. This includes explicit identifiers such as MAC addresses, the contents of management messages, and other protocol fields that the existing 802.11 protocol relies on to be sent in the clear. By obscuring these fields, I’ll show how we can we greatly increase the difficulty of identifying or profiling users from their transmissions in ways that are otherwise straightforward. Our design, called SlyFi, is nearly as efficient as existing schemes such as WPA for discovery, link setup, and data delivery despite its heightened protections; transmission requires only symmetric key encryption and reception requires a table lookup followed by symmetric key decryption. Experiments, using our implementation on Atheros 802.11 drivers, show that SlyFi can discover and associate with networks faster than 802.11 using WPA-PSK. The overhead SlyFi introduces in packet delivery is only slightly more than that added by WPA-CCMP encryption (10% vs. 3% decrease in throughput).

Biography

Ben Greenstein is a Research Scientist at Intel Research’s Seattle lablet and leads its Trustworthy Wireless project. He’s interested in developing wireless, distributed and potentially ubiquitous systems that improve everyday life. He received his doctorate in computer science from the University of California, Los Angeles, where he studied software systems for wireless embedded sensing devices with Deborah Estrin and Eddie Kohler. He holds a bachelor’s degree in history from the University of Pennsylvania. Ben has worked at AT&T, Intel Research Berkeley, and ICSI.