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The Path Less Travelled: Overcoming Tor’s Bottlenecks with Traffic Splitting

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Privacy Enhancing Technologies (PETS 2013)

Part of the book series: Lecture Notes in Computer Science ((LNSC,volume 7981))

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Abstract

Tor is the most popular low-latency anonymity network for enhancing ordinary users’ online privacy and resisting censorship. While it has grown in popularity, Tor has a variety of performance problems that result in poor quality of service, a strong disincentive to use the system, and weaker anonymity properties for all users. We observe that one reason why Tor is slow is due to low-bandwidth volunteer-operated routers. When clients use a low-bandwidth router, their throughput is limited by the capacity of the slowest node.

With the introduction of bridges—unadvertised Tor routers that provide Tor access to users within censored regimes like China—low-bandwidth Tor routers are becoming more common and essential to Tor’s ability to resist censorship. In this paper, we present Conflux, a dynamic traffic-splitting approach that assigns traffic to an overlay path based on its measured latency. Because it enhances the load-balancing properties of the network, Conflux considerably increases performance for clients using low-bandwidth bridges. Moreover, Conflux significantly improves the experience of users who watch streaming videos online.

Through live measurements and a whole-network evaluation conducted on a scalable network emulator, we show that our approach offers an improvement of approximately 30% in expected download time for web browsers who use Tor bridges and for streaming application users. We also show that Conflux introduces only slight tradeoffs between users’ anonymity and performance.

An extended version of this paper is available [1].

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Authors and Affiliations

  1. Cheriton School of Computer Science, University of Waterloo, Canada

    Mashael AlSabah, Kevin Bauer, Tariq Elahi & Ian Goldberg

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  1. Mashael AlSabah
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  2. Kevin Bauer
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  3. Tariq Elahi
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  4. Ian Goldberg
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Editors and Affiliations

  1. Palo Alto Research Center (PARC), 3333 Coyote Hill Road, 94034, Palo Alto, CA, USA

    Emiliano De Cristofaro

  2. Department of Computer Science and Engineering, University of Texas at Arlington, 500 UTA Boulevard, 76019, Arlington, TX, USA

    Matthew Wright

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AlSabah, M., Bauer, K., Elahi, T., Goldberg, I. (2013). The Path Less Travelled: Overcoming Tor’s Bottlenecks with Traffic Splitting. In: De Cristofaro, E., Wright, M. (eds) Privacy Enhancing Technologies. PETS 2013. Lecture Notes in Computer Science, vol 7981. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-39077-7_8

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  • DOI: https://doi.org/10.1007/978-3-642-39077-7_8

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