Towards a Scalable Censorship-Resistant Overlay Network based on WebRTC Covert Channels

Diogo Barradas, Nuno Santos

Abstract: In many regions of the world, nation-states enforce Internet censorship policies that prevent unrestricted access to information and services by their citizens. Over the years, many censorship circumvention tools have been proposed which, however, require either the deployment of a dedicated infrastructure within trusted ISPs, or are vulnerable to state-of-the-art traffic analysis techniques. To fill this gap, we propose to build a practical censorship-circumvention service that exhibits strong resistance against traffic analysis attacks. By relying on a recent proposal for creating covert channels through WebRTC streams, we discuss the design of a distributed system named Censorship-Resistant Overlay Network (CRON). CRON aims at offering to the users located in censored regions a set of services that allow them to locate proxies positioned in the free Internet region, and set up secure covert tunnels for accessing arbitrary sites on the Internet. We present the key challenges and explore the solutions in making CRON robust against state-level attacks.