Sheharbano Khattak, Tariq Elahi, Laurent Simon, Colleen M. Swanson, Steven J. Murdoch and Ian Goldberg
An increasing number of countries implement Internet censorship at different scales and for a variety of reasons. Several censorship resistance systems (CRSs) have emerged to help bypass such blocks. The diversity of the censor’s attack landscape has led to an arms race, leading to a dramatic speed of evolution of CRSs. The inherent complexity of CRSs and the breadth of work in this area makes it hard to contextualize the censor’s capabilities and censorship resistance strategies. To address these challenges, we conducted a comprehensive survey of CRSs-deployed tools as well as those discussed in academic literature-to systematize censorship resistance systems by their threat model and corresponding defenses. To this end, we first sketch a comprehensive attack model to set out the censor’s capabilities, coupled with discussion on the scope of censorship, and the dynamics that influence the censor’s decision. Next, we present an evaluation framework to systematize censorship resistance systems by their security, privacy, performance and deployability properties, and show how these systems map to the attack model. We do this for each of the functional phases that we identify for censorship resistance systems: communication establishment, which involves distribution and retrieval of information necessary for a client to join the censorship resistance system; and conversation, where actual exchange of information takes place. Our evaluation leads us to identify gaps in the literature, question the assumptions at play, and explore possible mitigations.
Hans Hanley, Yixin Sun, Sameer Wagh and Prateek Mittal
on Computer and communications security , pages 380–389. ACM, 2009.
 Tariq Elahi, Kevin Bauer, Mashael AlSabah, Roger Dingle-dine, and Ian Goldberg. Changing of the guards: A framework for understanding and improving entry guard selection in Tor. In Proceedings of the 2012 ACM Workshop on Privacy in the Electronic Society , pages 43–54. ACM, 2012.
 Nick Feamster and Roger Dingledine. Location diversity in Anonymity Networks. In Proceedings of the 2004 ACM workshop on Privacy in the electronic society , pages 66–76. ACM, 2004.
Gerry Wan, Aaron Johnson, Ryan Wails, Sameer Wagh and Prateek Mittal
, Mashael AlSabah, Roger Dingledine, and Ian Goldberg. Changing of the Guards: A Framework for Understanding and Improving Entry Guard Selection in Tor. In Proceedings of the 2012 ACM Workshop on Privacy in the Electronic Society , WPES ’12, 2012.
 Nick Feamster and Roger Dingledine. Location Diversity in Anonymity Networks. In Proceedings of the 2004 ACM Workshop on Privacy in the Electronic Society , WPES ’04, 2004.
 Lixin Gao and Jennifer Rexford. Stable Internet Routing Without Global Coordination. IEEE/AM Transactions on Networking , 9(6), 2001
Gilad Asharov, Daniel Demmler, Michael Schapira, Thomas Schneider, Gil Segev, Scott Shenker and Michael Zohner
 S. Machiraju and R. H. Katz. Leveraging BGP dynamics to reverse-engineer routing policies. Technical Report UCB/EECS-2006-61, EECS Department, University of California, Berkeley, May 2006.
 V. Giotsas and S. Zhou. Inferring AS relationships from BGP attributes. CoRR , abs/1106.2417, 2011.
 D. Gupta, A. Segal, A. Panda, G. Segev, M. Schapira, J. Feigenbaum, J. Rexford, and S. Shenker. A new approach to interdomain routing based on secure multi-party computation. In Workshop on Hot Topics in Networks (HotNets’12) , pages 37