Thwarting web censorship with untrusted messenger discovery

Nick Feamster, Magdalena Balazinska, Winston Wang, Hari Balakrishnan, David Karger

Research output: Chapter in Book/Report/Conference proceedingChapter

16 Scopus citations

Abstract

All existing anti-censorship systems for the Web rely on proxies to grant clients access to censored information. Therefore, they face the proxy discovery problem: how can clients discover the proxies without having the censor discover and block these proxies? To avoid widespread discovery and blocking, proxies must not be widely published and should be discovered in-band. In this paper, we present a proxy discovery mechanism called keyspace hopping that meets this goal. Similar in spirit to frequency hopping in wireless networks, keyspace hopping ensures that each client discovers only a small fraction of the total number of proxies. However, requiring clients to independently discover proxies from a large set makes it practically impossible to verify the trustworthiness of every proxy and creates the possibility of having untrusted proxies. To address this, we propose separating the proxy into two distinct components - the messenger, which the client discovers using keyspace hopping and which simply acts as a gateway to the Internet; and the portal, whose identity is widely-published and whose responsibility it is to interpret and serve the client's requests for censored content. We show how this separation, as well as in-band proxy discovery, can be applied to a variety of anti-censorship systems.

Original languageEnglish (US)
Title of host publicationLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
EditorsRoger Dingledine
PublisherSpringer Verlag
Pages125-140
Number of pages16
ISBN (Print)9783540409564
DOIs
StatePublished - 2003

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume2760
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • Computer Science(all)

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  • Cite this

    Feamster, N., Balazinska, M., Wang, W., Balakrishnan, H., & Karger, D. (2003). Thwarting web censorship with untrusted messenger discovery. In R. Dingledine (Ed.), Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) (pp. 125-140). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 2760). Springer Verlag. https://doi.org/10.1007/978-3-540-40956-4_9