When bitcoin is spent, remainders are re-encoded & combined - how do you separate out any ill-gotten gains from the legitimate hard-earned lucre? Outlining his team's solution: Professor Ross Anderson of the Computer Laboratory, University of Cambridge. NB comments disabled purely due to huge amounts of spam. Why Bitcoin isn't cash: Coming Soon Elliptic Curve Backdoor: https://www.youtube.com/watch?v=nybVFJVXbww https://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: https://bit.ly/nottscomputer Computerphile is a sister project to Brady Haran's Numberphile. More at http://www.bradyharan.com/