Has anyone mentioned Dan Brown's "Digital Fortress"?
If your son knows even a little bit about cryptography then stay away from this book. It's full of factual errors. Dan Brown doesn't seem to grasp even the basic understanding of exponential complexity. I was ready to toss the book across the room after reading only a few pages. I finished it but only because I was curious how much more he can mess it up.
If you want a good intro into crypto, then try some books by Neal Stephenson. Neal was a GT kid himself. Neal weaves in culture, ethinicity, history, language, computers, and crypto into his a books.
http://en.wikipedia.org/wiki/Neal_Stephenson
