I n April 1999, Bruce Schneier, mathematician, digital security expert and unlikely hacker-scene hero, had an epiphany. It prodded him to reorganize his company, Counterpane Internet Security, and altered his view of securing computer systems. Schneier, the creator of two widely used data-scrambling formulas and author of the definitive Applied Cryptography , realized that he and his colleagues were trained to view security as a hopeless prophylactic, a passive approach that relies too heavily on complex technologies to keep hackers and criminals out. Add a firewall and a pinch of encryption, and eventually you'll have a secure system. He concluded that technology, no matter how complex, can't solve all our problems.
Security is rooted in the physical world.
The physical world is not logical. People don't play along. Schneier provides a series of cognitive exercises designed to get crime-inspiring synapses firing. We can pay with a fake credit card, a fake check or counterfeit cash. We can persuade another patron to leave the restaurant without eating and eat his food.