Circumvention of censorship of internet access and publication

Abstract

Internet censorship of one form or another affects on the order of half of all internet users. Previous work has studied this censorship, and proposed techniques for circumventing it, ranging from making proxy servers available to censored users, to tunneling internet connections through services such as voice or video chat, to embedding censorship circumvention in cloud platforms' front-end servers or even in ISP's routers.

This dissertation describes a set of techniques for circumventing internet censorship building on and surpassing prior efforts. As is always the case, there are tradeoffs to be made: some of this work emphasizes deployability, and some aims for unstoppable circumvention with the assumption of significant resources. However, the latter techniques are not merely academic thought experiments: this dissertation also describes the experience of successfully deploying such a technique, which served tens of thousands of users.

While the solid majority of previous work, as well as much of the work presented here, is focused on governments blocking access to sites and services hosted outside of their country, the rise of social media has created a new form of internet censorship. A country may block a social media platform, but have its own domestic version, on which it tightly controls what can be said. This dissertation describes a system for enabling users of such a platform to monitor for post deletions, and distribute the contents to other users.