SlyFi
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SlyFi: Improving Wireless Privacy with an Identifier-Free Link Layer Protocol
SlyFi is 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,
we greatly increase the difficulty of identifying or profiling users from their transmissions in ways that are otherwise straightforward. Our design 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 higher than that added by WPA-CCMP encryption
(10% vs. 3% decrease in throughput).
Publications
Improving Wireless Privacy with an Identifier-Free Link Layer Protocol. Ben Greenstein, Damon McCoy, Jeffrey Pang, Tadayoshi Kohno, Srinivasan Seshan, David Wetherall. MobiSys '08: 6th International Conference on Mobile Systems, Application, and Services, 2008, Breckenridge, CO. Best Paper Award. [1]
