I just got done with reading 'Digital Fortress' by Dan Brown. Picked it up with huge expectations after reading The Da Vinci Code, only to be extremely disappointed.
The end was the most tortuous, imagine the top guys at the NSA (supposedly the accumulation of the brightest minds on the planet, according to the novel), not knowing their seventh standard chemistry. I'd expect them to figure out the difference between the isotopes of Uranium, an element we hear and read more than we do about others, O2 for example.
If you're reading this book, be ready to be told the "very basic" facts of cryptography, in a way so as to demo the "superlative" cryptography knowledge of the lead characters.
The Da Vinci Code was good. Digital Fortress isn't.