Which is the book I'm reading now.
I really don't have much time to read, as you can imagine working on MAME eats up most of my spare time. However I try to read something even if it means just a couple of pages per day.
I had read the bestseller The Da Vinci Code previously, and didn't feel any urge to read another book from the same author, especially after I noticed that all bookstores are now prominently displaying his previous works, which had went entirely unnoticed until the success of The Da Vinci Code.
Digital Fortress in particular was written in 1998. The publisher must have been unable to find any positive review to reprint on the back cover, because they resorted to quoting "Praise for The Da Vinci Code". However I was intrigued bu the theme of the book, which is cryptography - and I was able to borrow it from a friend, so I gave it a try :)
The problem with fiction is that you must be able to suspend disbelief to immerse in the story. This isn't easy if what is being thrown at you makes no sense at all. This was also a problem with The Da Vinci Code, of course, but not knowing much about art history it was easier to fool me. Mathematics is supposed to be my field, so fooling me gets a little bit harder.
Right at the beginning of the book, on page 29, the author introduces Julius Caesar as "the first code-writer in history", and talks about a "'perfect square' cipher box" he supposedly use. This is a transposition cipher, which consists of arranging the cleartext in a square and reading it by columns to get the ciphertext.
Well, I had never heard of this "Caesar's box" cipher. The encryption commonly associated with Caesar is the one called "Caesar's cipher", and it is a substitution cipher: replace every letter with the one k places after it in the alphabet, so e.g. A becomes D, B becomes E, and so on.
A transposition cipher similar to the one mentioned by Dan Brown was used in Sparta, a few centuries before Caesar's birth.
OK, never mind. After all, I might just be ignorant not knowing about the Caesar's Box. Unfortunately, on page 34 Dan Brown talks about public-key encryption, and what he says makes little sense.
The comment that modern codes are "computer-generated has functions that employed chaos theory and multiple symbolic alphabets" was also funny - it reminded me of this :)