research-article

BridgeSPA: improving Tor bridges with single packet authorization

Authors:

Urs HengartnerAuthors Info & Claims

WPES '11: Proceedings of the 10th annual ACM workshop on Privacy in the electronic society

Pages 93 - 102

https://doi.org/10.1145/2046556.2046569

Published: 17 October 2011 Publication History

Abstract

Tor is a network designed for low-latency anonymous communications. Tor clients form circuits through relays that are listed in a public directory, and then relay their encrypted traffic through these circuits. This indirection makes it difficult for a local adversary to determine with whom a particular Tor user is communicating. In response, some local adversaries restrict access to Tor by blocking each of the publicly listed relays. To deal with such an adversary, Tor uses bridges, which are unlisted relays that can be used as alternative entry points into the Tor network. Unfortunately, issues with Tor's bridge implementation make it easy to discover large numbers of bridges. An adversary that hoards this information may use it to determine when each bridge is online over time. If a bridge operator also browses with Tor on the same machine, this information may be sufficient to deanonymize him. We present BridgeSPA as a method to mitigate this issue. A client using BridgeSPA relies on innocuous single packet authorization (SPA) to present a time-limited key to a bridge. Before this authorization takes place, the bridge will not reveal whether it is online. We have implemented BridgeSPA as a working proof-of-concept, which is available under an open-source licence.

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Cited By

Zang YCai CDong WXu LWang C(2024)HiddenTor: Toward a User-Centric and Private Query System for Tor BridgeDB2024 IEEE 44th International Conference on Distributed Computing Systems (ICDCS)10.1109/ICDCS60910.2024.00119(1260-1271)Online publication date: 23-Jul-2024
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Jia ZWu WJia ZYang XWang QLi H(2022)Enhanced Mobile IoT Security Protection Method Based on CPK and Zero Trust2022 IEEE 22nd International Conference on Communication Technology (ICCT)10.1109/ICCT56141.2022.10073095(911-916)Online publication date: 11-Nov-2022
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Index Terms

BridgeSPA: improving Tor bridges with single packet authorization
1. Security and privacy
  1. Network security

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cover image ACM Conferences

WPES '11: Proceedings of the 10th annual ACM workshop on Privacy in the electronic society

October 2011

192 pages

ISBN:9781450310024

DOI:10.1145/2046556

General Chair:
Yan Chen
Northwestern University, USA
,
Program Chair:
Jaideep Vaidya
Rutgers University, USA

Copyright © 2011 ACM.

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Published: 17 October 2011

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October 17, 2011

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Overall Acceptance Rate 106 of 355 submissions, 30%

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https://doi.org/10.1109/ICDCS60910.2024.00119
Jia ZWu WJia ZYang XWang QLi H(2022)Enhanced Mobile IoT Security Protection Method Based on CPK and Zero Trust2022 IEEE 22nd International Conference on Communication Technology (ICCT)10.1109/ICCT56141.2022.10073095(911-916)Online publication date: 11-Nov-2022
https://doi.org/10.1109/ICCT56141.2022.10073095
Chen YZhang YZou JTan ZHuang YHu N(2022)Stealth: A Heterogeneous Covert Access Channel for Mix-net2022 7th IEEE International Conference on Data Science in Cyberspace (DSC)10.1109/DSC55868.2022.00023(118-125)Online publication date: Jul-2022
https://doi.org/10.1109/DSC55868.2022.00023
Wang HLuo XSun Y(2020)An Obfs-based Tor Anonymous Communication Anline Identification Method2020 6th International Conference on Big Data and Information Analytics (BigDIA)10.1109/BigDIA51454.2020.00064(361-366)Online publication date: Dec-2020
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Khan SShiraz MBoroumand LGani AKhan M(2017)Towards port-knocking authentication methods for mobile cloud computingJournal of Network and Computer Applications10.1016/j.jnca.2017.08.01897:C(66-78)Online publication date: 1-Nov-2017
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Ensafi RFifield DWinter PFeamster NWeaver NPaxson VCho KFukuda KPai VSpring N(2015)Examining How the Great Firewall Discovers Hidden Circumvention ServersProceedings of the 2015 Internet Measurement Conference10.1145/2815675.2815690(445-458)Online publication date: 28-Oct-2015
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Winter PPulls TFuss JSadeghi AForesti S(2013)ScrambleSuitProceedings of the 12th ACM workshop on Workshop on privacy in the electronic society10.1145/2517840.2517856(213-224)Online publication date: 4-Nov-2013
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