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TorBricks: Blocking-Resistant Tor Bridge Distribution

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Stabilization, Safety, and Security of Distributed Systems (SSS 2017)

Part of the book series: Lecture Notes in Computer Science ((LNTCS,volume 10616))

Abstract

Tor is currently the most popular network for anonymous Internet communication. It critically relies on volunteer nodes called bridges to relay Internet traffic when a user’s ISP blocks connections to Tor. Unfortunately, current methods for distributing bridges are vulnerable to malicious users who obtain and block bridge addresses. In this paper, we propose TorBricks, a protocol for privacy-preserving distribution of Tor bridges to n users, even when an unknown number \({t < n}\) of these users are controlled by a malicious adversary. TorBricks distributes \(O(t\log {n})\) bridges and guarantees that all honest users can connect to Tor with high probability after \(O(\log {t})\) rounds of communication with the distributor. Our empirical evaluations show that TorBricks requires at least 20x fewer bridges and two orders of magnitude less running time than the state-of-the-art.

M. Zamani—This work was done when the author was a student at the University of New Mexico.

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Notes

  1. 1.

    By honest users, we mean the users that are not controlled by the censor to obtain the bridge addresses assigned to them.

  2. 2.

    Completely blocking a service such as email would likely impose significant economic consequences for censors. However, unfortunately, email alone does not enable real-time interaction with the Web.

  3. 3.

    We are not aware of any efficient decentralized algorithm to partition a set of n elements into k randomly-chosen disjoint subsets.

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Authors and Affiliations

  1. Visa Research, Palo Alto, CA, USA

    Mahdi Zamani

  2. University of New Mexico, Albuquerque, NM, USA

    Jared Saia & Jedidiah Crandall

Authors
  1. Mahdi Zamani
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  2. Jared Saia
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  3. Jedidiah Crandall
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Correspondence to Mahdi Zamani .

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Editors and Affiliations

  1. University of Liverpool, Liverpool, United Kingdom

    Paul Spirakis

  2. Chalmers University of Technology, Gothenburg, Sweden

    Philippas Tsigas

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Zamani, M., Saia, J., Crandall, J. (2017). TorBricks: Blocking-Resistant Tor Bridge Distribution. In: Spirakis, P., Tsigas, P. (eds) Stabilization, Safety, and Security of Distributed Systems. SSS 2017. Lecture Notes in Computer Science(), vol 10616. Springer, Cham. https://doi.org/10.1007/978-3-319-69084-1_32

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  • DOI: https://doi.org/10.1007/978-3-319-69084-1_32

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  • Publisher Name: Springer, Cham

  • Print ISBN: 978-3-319-69083-4

  • Online ISBN: 978-3-319-69084-1

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