Those who know how to fix know how to destroy as well

From Stephen J. Dubner’s interview with Bruce Schneier in “Bruce Schneier Blazes Through Your Questions” (The New York Times: 4 December 2007):

This is true in many aspects of our society. Here’s what I said in my book, Secrets and Lies (page 389): “As technology becomes more complicated, society’s experts become more specialized. And in almost every area, those with the expertise to build society’s infrastructure also have the expertise to destroy it. Ask any doctor how to poison someone untraceably, and he can tell you. Ask someone who works in aircraft maintenance how to drop a 747 out of the sky without getting caught, and he’ll know. Now ask any Internet security professional how to take down the Internet, permanently. I’ve heard about half a dozen different ways, and I know I haven’t exhausted the possibilities.”