As the first book of Dan Brown, DIGITAL FORTRESS is quite an OK triller. Let's say his bestselling novel THE DA VINCI CODE is more focused on religion, then DIGITAL FORTRESS talks mainly about cryptography and computer science, which are quite favorable topics to me too.

 

Looking at the big picture, DIGITAL FORTRESS has represented the fierce battle over digital privacy from both sides, NSA and EFF. On one hand, we've got Commander Strathmore saying that they are striving for national security and honor. Just to protest their people do they need limitless access to all digital information over the world. On the other hand, we've got EFF and individuals like Dr. Tankado claiming that it is human right to privacy even if that means unbreakable encryption. Before reading Digital Fortress, I couldn't choose a side. After reading it, I still can't choose a side. At least Brown wasn't blatantly biased (although I detected a hint of pro-NSA bias).

 

Obviously, everything else about the book was great and the author just happened to be math challenged. There are so many fatal "bugs" here and there about the idea of TRANSLTR and DIGITAL FORTRESS. Eventually it turns out the so-called unbreakable code is just simply a worm. The whole NSA is tricked by Dr. Tankado. The Bergofsky's Principle still stands. However, after google-ing I can't find any clue about The Bergofsky's Principle but instead, I discovered the "one-time pad", a cipher that cannot be broken. The point is, any plaintext of the same length is a possible decryption of a ciphertext.

 

Not only that, the idea that TRANSLTR can brute force any encrypted text, without knowing the algorithm used, is absurd. Never mind the time for breaking a code usually doesn't grow linearly with key length, as suggested in the book, but exponentially. Therefore there exists such a code can be considered "practically safe" (say 256 bit), simply because the time to decode it is beyond universe limit. Unless the quantum computer science makes ground-breaking progress in future. And unless there is some backdoor.  

 

My conclusion is, the moral of the story is excellent, though it lacks of basic mathematical/cryptographic knowledge. It is quite pleasant if you treat it as simple as a romance or suspending triller. However, if you are sincere to learn more about cryptography, I would suggest THE CODE BOOK by Simon Singh is a better choice.