Products used for managing network traffic and restricting access to Web content represent a dual-use technology. While they were designed to improve performance and protect users from inappropriate content, these products are also used to censor the Web by authoritarian regimes around the globe. This dual use has not gone unnoticed, with Western governments placing restrictions on their export.Our contribution is to present methods for identifying installations of URL filtering products and confirming their use for censorship. We first present a methodology for identifying externally visible installations of URL filtering products in ISPs around the globe. Further, we leverage the fact that many of these products accept user-submitted sites for blocking to confirm that a specific URL filtering product is being used for censorship. Using this method, we are able to confirm the use of McAfee SmartFilter in Saudi Arabia and the United Arab Emirates (UAE) and Netsweeper in Qatar, the UAE, and Yemen. Our results show that these products are being used to block a range of content, including oppositional political speech, religious discussion and gay and lesbian material, speech generally protected by international human rights norms.

In this study, we take another look at 5 years of web censorship data gathered by the OpenNet Initiative in 77 countries using user-based testing with locally relevant content. Prior to our work, this data had been analyzed with little automation, focusing on what content had been blocked, rather than how blocking was carried out. In this study, we use more rigorous automation to obtain a longitudinal, global view of the technical means used for web censorship. We also identify blocking that had been missed in prior analyses. Our results point to considerable variability in the technologies used for web censorship, across countries, time, and types of content, and even across ISPs in the same country. In addition to characterizing web censorship in countries that, thus far, have eluded technical analysis, we also discuss the implications of our observations on the design of future network measurement platforms and circumvention technologies.

In this paper, we present an analysis of over one year and a half of data from tracking the censorship and surveillance keyword lists of two instant messaging programs used in China. Through reverse engineering of TOM-Skype and Sina UC, we were able to obtain the URLs and encryption keys for various versions of these two programs and have been downloading the keyword blacklists daily. This paper examines the social and political contexts behind the contents of these lists, and analyzes those times when the list has been updated, including correlations with current events.

No abstract

Information controls are actions intended to deny, disrupt, monitor, or secure information for political ends. They can be implemented using a wide variety of technical and nontechnical means. Political contests over the control of information are heightened around important events, such as major anniversaries, armed conflicts, protests, and elections. In this paper, we offer a comparative case study of online censorship of the circumvention tool Psiphon during the Iranian elections in 2016 and 2013, drawing on unique access to analytics data from Psiphon. We find that the Iranian regime developed its censorship approach in two ways, deploying blocking that was more targeted and strategically timed in the more recent case. Evidence suggests that the regime relaxed censorship of Psiphon during the official campaign period for the 2016 election. The apparent objective of this new approach was to control access to information while minimizing the political consequences of doing so.