The World Wide Web is a prime facilitator of free speech; many people rely on it to voice their views and to gain access to information those traditional publishing venues may be loath to publish. However, over the past few years, many countries, political regimes, and corporations have attempted to monitor and often restrict access to portions of the Web by clients who use networks they control. Many of these attempts have been successful, and the use of the Web as a free-flowing medium for information exchange is being severely compromised. Several countries filter Internet content at their borders, fearful of alternate political views or external influences. For example, China forbids access to many news sites that have been critical of the country?s domestic policies. Saudi Arabia is currently soliciting content filter vendors to help block access to sites that the government deems inappropriate for political or religious reasons . Germany censors all Nazi-related material. Australia?s laws ban pornography. In addition, Internet censorship repeatedly threatens to cross political boundaries. For example, the U.S. Supreme Court recently rejected France?s request to censor Nazi-related material on Yahoo?s site . Censorship and surveillance also extend into free enterprise, with several companies in the U.S. reportedly blocking access to sites that are not related to conducting business. In addition to blocking sites, many companies routinely monitor their employees?. This paper focuses on the challenging technical problems of circumventing Web censorship and largely ignores the many related political, legal, and policy issues. In particular, we investigate how to leverage Web communication with accessible server?s inorder to surreptitiously retrieve censored content, while simultaneously maintaining plausible deniability against receiving that content. To this end, we develop a covert communication tunnel that securely hides the exchange of censored content in normal, innocuous Web transactions.Our system, called Infranet, consists of requesters and responders communicating over this covert tunnel. A requester, running on a user?s computer, first uses the tunnel to request censored content. Upon receiving the request, the responder, a standard public Web server running Infranet software retrieves the sought content from the Web and returns it to the requester via the tunnel.1The covert tunnel protocol between an Infranet requester and responder must be difficult to detect and block. More specifically, a censor should not be able to detect that a Web server is an Infranet responder or that a client is an In-franet requester. Nothing in their HTTP transactions sought to arouse suspicion. The Infranet tunnel protocol uses novel techniques for covert upstream communication. It modulates covert messages on standard HTTP requests for uncensored content using a confidentially negotiated function which maps URLs to message fragments that compose requests for censored protocol leverages existing data hiding techniques, such as steganography. While steganography provides little defense against certain attacks, we are confident that the ideas we present can be used in conjunction with other data hiding techniques.