The awesome article exploring and testing the protection mechanisms, with pictures, from ~2009 (actually earlier probably, that's the "last modified" date of th

The awesome article exploring and testing the protection mechanisms, with pictures, from ~2009 (actually earlier probably, that's the "last modified" date of the article): http://www.cl.cam.ac.uk/~sjm217/projects/currency/ http://www.cl.cam.ac.uk/~sjm217/projects/currency/ (author notes his own earlier presentations on this topic starting 2004)