Governments can censor access to the web, but how do they restrict access? Sheharbano Khattak, Research Assistant at the University of Cambridge Computer Laboratory takes us through the methods. EXTRA BITS: https://youtu.be/nqbyS_Z74nc http://www.facebook.com/computerphile https://twitter.com/computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: http://bit.ly/nottscomputer Computerphile is a sister project to Brady Haran's Numberphile. More at http://www.bradyharan.com