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Circumvention Publications

The Evolving Landscape of Internet Control
By Hal Roberts, Ethan Zuckerman, Rob Faris, Jillian York, and John Palfrey
This paper summarizes the results of the studies we have undertaken in order to better understand the control of the Internet in less open societies. It provides an overview of our research in the context recent changes in the methods used to control online speech, and some thoughts on the challenges to online speech in the immediate future.

International Bloggers and Internet Control
By Hal Roberts, Ethan Zuckerman, Jillian York, Rob Faris, and John Palfrey
Infringements on Internet freedom, particularly through Internet filtering and surveillance, have inspired activists and technologists to develop technological counter-measures, most notably circumvention tools to defeat Internet filters and anonymity tools to help protect user privacy and avoid online surveillance efforts. However, despite the perceived importance of this field, relatively little is known about the demand for and usage patterns of these tools. In December 2010, we surveyed a sample of international bloggers to better understand how, where, why, and by whom these tools are being used.

Circumvention Tool Evaluation
By Hal Roberts, Ethan Zuckerman, and John Palfrey
This paper evaluates 19 circumvention tools tested in five countries. In this report, we focus on questions of utility—the ability for a tool to be installed and used in a particular location, and the accuracy and speed of the tool. Additionally, we address concerns about security, usability and openness when appropriate.

2010 Circumvention Tool Usage Report
By Hal Roberts, Ethan Zuckerman, Jillian York, Rob Faris, John Palfrey
Circumvention tools allow users to bypass Internet filtering to access content otherwise blocked by governments, workplaces, schools, or even the blocked sites themselves. There are a number of different types of these tools: blocking-resistant tools, simple web proxies, virtual private network (VPN) services, and open HTTP/SOCKS proxies. But every type of circumvention tool provides the same basic functionality — proxying user connections to provide access to otherwise blocked sites. In the following report, we use a variety of methods to evaluate the usage of the first three of these four types of tools to test two hypotheses. First, even though much of the media attention on circumvention tools has been given to a handful of tools — notably Freegate, Ultrasurf, Tor, and Hotspot Shield — we find that these tools represent only a small portion of overall circumvention usage and that the attention paid to these tools has been disproportionate to their usage, especially when compared to the more widely used simple web proxies. Second, even when including the more widely-used simple web proxies, we find that overall usage of circumvention tools is still very small in proportion to the number of Internet users in countries with substantial national Internet filtering.

2007 Circumvention Landscape Report: Methods, Uses, and Tools
By Hal Roberts, Ethan Zuckerman, John Palfrey
As the Internet has exploded over the past fifteen years, recently reaching over a billion users, dozens of national governments from China to Saudi Arabia have tried to control the network by filtering out content objectionable to the countries for any of a number of reasons. A large variety of different projects have developed tools that can be used to circumvent this filtering, allowing people in filtered countries access to otherwise filtered content. In this report, we describe the mechanisms of filtering and circumvention and evaluate ten projects that develop tools that can be used to circumvent filtering: Anonymizer, Ultrareach, DynaWeb Freegate, Circumventor/CGIProxy, Psiphon, Tor, JAP, Coral, and Hamachi. We evaluated these tools in 2007 -- using both tests from within filtered countries and tests within a lab environment -- for their utility, usability, security, promotion, sustainability, and openness. We find that all of the tools use the same basic mechanisms of proxying and encryption but that they differ in their models of hosting proxies. Some tools use proxies that are centrally hosted, others use proxies that are peer hosted, and others use re-routing methods that use a combination of the two. We find that, in general, the tools work in the sense that they allow users to access pages that are otherwise blocked by filtering countries but that performance of the tools is generally poor and that many tools have significant, unreported security vulnerabilities.