Thanks for the reference!  I read Singh's book myself a few years ago and found it very entertaining and informative.  If I recall correctly, he also discusses the future of cryptology:  'quantum cryptology'.  Unfortunately I've lost my copy (I think I loaned it to someone and never got it back), so I didn't reference it for this article; but I'd definitely recommend it to anyone who wants to know more about the history of cryptology.  Here's a link to it at Amazon:  http://www.amazon.com/exec/obidos/tg/detail/-/0385495323/qid=1123680339/sr=8-2/ref=pd_bbs_sbs_2/103-0153168-7501472?v=glance&s=books&n=507846

He also has another book, "Fermat's Enigma", about how one of the world's hardest mathematical problems was solved.  It's very good as well.  Here's that link:  http://www.amazon.com/exec/obidos/tg/detail/-/0385493622/qid=1123680339/sr=8-3/ref=pd_bbs_sbs_3/103-0153168-7501472?v=glance&s=books&n=507846

Thanks again!