Bruce Schneier is one of the most famous security specialist of the current era. He was a "nerdy guy" at the beginning of his career but later he became a brilliant intellectual man able to give one of the most valuable talk on security I heard so far. Fantastic speech for IT course students and experienced professionals alike!
I so agree with Bruce, that I'm planning to change my first lesson on security following his idea of "three blocks". I'll think about it. PS, I want to thank also TED which always provides the greatest talks on the web.