This project studies Internet censorship as practiced by some of today's nation-states. The effort emphasizes analyzing the techncial measures used by censors to perform censorship, the extent to which their operations inflict collateral damage (unintended blocking, or blocking of activity wholly outside the censoring nation), and vulnerabilities due to the specifics of how censorship operates. Regarding this latter, we analyze flaws in either how the censorship monitoring detects particular network traffic to suppress, or in how the monitor then attempts to block or disrupt the target traffic. This facet of the research focuses on forms of monitoring that eavesdrop on network links, analyze copies of transmitted traffic, and then inject forged traffic, seemingly sent from one of the communication endpoints to the other, instructing the other party to cease communication. Such "on-path" monitoring is subject to a number of potential manipulations and evasions due to the inexact view the monitor has of the comunication as actually seen by the communicating parties. We in particular then work towards developing tools and changes to Internet technology that can resist these forms of disruption and thus enable users to access the Internet freely.
