Chipping Away at Censorship Firewalls with User-Generated Content

Oppressive regimes and even democratic governments restrict Internet access. Existing anti-censorship systems often require users to connect through proxies, but these systems are relatively easy for a censor to discover and block. This paper offers a possible next step in the censorship arms race: rather than relying on a single system or set of proxies to circumvent censorship firewalls, we explore whether the vast deployment of sites that host user-generated content can breach these firewalls. To explore this possibility, we have developed Collage, which allows users to exchange messages through hidden channels in sites that host user-generated content. Collage has two components: a message vector layer for embedding content in cover traffic; and a rendezvous mechanism to allow parties to publish and retrieve messages in the cover traffic. Collage uses user-generated content (e.g., photo-sharing sites) as "drop sites" for hidden messages. To send a message, a user embeds ...

• Type: Journal
• Year: 2010
• Where: USS
• Authors: Sam Burnett, Nick Feamster, Santosh Vempala
• Keywords: Collage, Cover Traffic, Operating System, User-generated Content, USS 2010