Infranet: Circumventing web censorship and surveillance

TitleInfranet: Circumventing web censorship and surveillance
Publication TypeJournal Articles
Year of Publication2002
AuthorsFeamster N, Balazinska M, Harfst G, Balakrishnan H, Karger D
JournalProceedings of the 11th USENIX Security Symposium
Pagination247 - 262
Date Published2002///
Abstract

An increasing number of countries and companies routinely block or monitor access to parts of the Internet. To counteract these measures, we propose Infranet, a system that enables clients to surreptitiously retrieve sensitive content via cooperating Web servers distributed across the global Internet. These Infranet servers provide clients access to censored sites while continuing to host normal uncensored content. Infranet uses a tunnel protocol that provides a covert communication channel between its clients and servers, modulated over standard HTTP transactions that resemble innocuous Web browsing. In the upstream direction, Infranet clients send covert messages to Infranet servers by associating meaning to the sequence of HTTP requests being made. In the downstream direction, Infranet servers return content by hiding censored data in uncensored images using steganographic techniques. We describe the design, a prototype implementation, security properties, and performance of Infranet. Our security analysis shows that Infranet can successfully circumvent several sophisticated censoring techniques.