JavaScript anticensorship proxies

Censorship is an everyday reality for many of the world's Internet users. Users turn to circumvention systems like Tor; censors respond by blacklisting the addresses of those systems. This talk will cover the use of "flash proxies" to evade such blacklisting. Flash proxies-which despite the name, do not use Adobe Flash-are miniature proxies implemented in JavaScript running in web browsers. Browsers can become temporary circumvention proxies just by viewing a web page, and stop being a proxy just by closing a tab. Browsers provide a large, diverse pool of IP addresses, which change too quickly to be effectively blocked by blacklisting. The system, originally a research idea, is now deployed on the Internet. The talk will discuss the overall design of the flash proxy system, and how it fits into a larger circumvention scheme. It will include challenges in implementation and deployment, and highlight some future directions for development. Flash proxies were the subject of a research paper, "Evading Censorship with Browser-Based Proxies" by David Fifield, Nate Hardison, Jonathan Ellithorpe, Emily Stark, Roger Dingledine, Phil Porras, and Dan Boneh; and the system now has more contributors from the Tor Project.

Speaker: David Fifield, Stanford