Circumventing censorship with collage

TitleCircumventing censorship with collage
Publication TypeConference Papers
Year of Publication2010
AuthorsBurnett S, Feamster N, Vempala S
Conference NameProceedings of the ACM SIGCOMM 2010 conference
Date Published2010///
Conference LocationNew York, NY, USA
ISBN Number978-1-4503-0201-2
KeywordsAvailability, censorship

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. We explore 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 use the vast deployment of sites that host user-generated content to breach these firewalls. We have developed Collage, which allows users to exchange messages through hidden channels in sites that host user-generated content. To send a message, a user embeds it into cover traffic and posts the content on some site, where receivers retrieve this content. Collage makes it difficult for a censor to monitor or block these messages by exploiting the sheer number of sites where users can exchange messages and the variety of ways that a message can be hidden. We have built a censorship-resistant news reader using Collage that can retrieve from behind a censorship firewall and show Collage's effectiveness with a live demonstration of its complete infrastructure.