DefenestraTor: Throwing out windows in Tor

Mashael Alsabah, Kevin Bauer, Ian Goldberg, Dirk Grunwald, Damon McCoy, Stefan Savage, Geoffrey M. Voelker

Research output: Chapter in Book/Report/Conference proceedingConference contribution

23 Citations (Scopus)

Abstract

Tor is one of the most widely used privacy enhancing technologies for achieving online anonymity and resisting censorship. While conventional wisdom dictates that the level of anonymity offered by Tor increases as its user base grows, the most significant obstacle to Tor adoption continues to be its slow performance. We seek to enhance Tor's performance by offering techniques to control congestion and improve flow control, thereby reducing unnecessary delays. To reduce congestion, we first evaluate small fixed-size circuit windows and a dynamic circuit window that adaptively re-sizes in response to perceived congestion. While these solutions improve web page response times and require modification only to exit routers, they generally offer poor flow control and slower downloads relative to Tor's current design. To improve flow control while reducing congestion, we implement N23, an ATM-style per-link algorithm that allows Tor routers to explicitly cap their queue lengths and signal congestion via back-pressure. Our results show that N23 offers better congestion and flow control, resulting in improved web page response times and faster page loads compared to Tor's current design and other window-based approaches. We also argue that our proposals do not enable any new attacks on Tor users' privacy.

Original languageEnglish
Title of host publicationLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Pages134-154
Number of pages21
Volume6794 LNCS
DOIs
Publication statusPublished - 2011
Externally publishedYes
Event11th International Symposium on Privacy Enhancing Technologies, PETS 2011 - Waterloo, ON
Duration: 27 Jul 201129 Jul 2011

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume6794 LNCS
ISSN (Print)03029743
ISSN (Electronic)16113349

Other

Other11th International Symposium on Privacy Enhancing Technologies, PETS 2011
CityWaterloo, ON
Period27/7/1129/7/11

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ASJC Scopus subject areas

  • Computer Science(all)
  • Theoretical Computer Science

Cite this

Alsabah, M., Bauer, K., Goldberg, I., Grunwald, D., McCoy, D., Savage, S., & Voelker, G. M. (2011). DefenestraTor: Throwing out windows in Tor. In Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) (Vol. 6794 LNCS, pp. 134-154). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 6794 LNCS). https://doi.org/10.1007/978-3-642-22263-4_8