01/01/2001

77 Mass Ave

Continued from page 3

By Technology Review

Subverting Internet Censorship

Researchers in the Computer Science and Artificial Intelligence Laboratory are developing software that allows users to covertly browse blocked or censored content on the Web. Foreign governments censors would have a tough time detecting it. Intelligence agencies could use the software to gather information, and workers could browse blocked sites without their employers knowledge.

The project, called Infranet, is the brainchild of Professors David Karger and Hari Balakrishnan, who started it in 2001. Infranet software connects a computer to a cooperating, unblocked Web server and requests blocked content through a special sequence of what appear to be requests for innocent pages. To censors, it all looks like normal Web browsing. In reality, the server retrieves content from a blocked website and delivers it to the users computer hidden within picture files. An adversary that can see all traffic from a client should not even be able to tell that anything out of the ordinary is going on, says Nick Feamster 00, Mng 01, a graduate student working on Infranet.

According to Feamster, most commercially available applications that protect Web browsing use a kind of encryption that is itself noticeable to censors, who can simply block traffic to encrypted sites, even if they cant tell what information is being exchanged. The MIT researchers are currently testing a working version of Infranet on PlanetLab, an international platform for the development of Internet applications.