Digital Fortress - 6 mistakes

Factual error: The director in the story, Leland Fontaine, is a civilian, and we are told that he worked his way up through the ranks of the NSA. However, this would not occur in real life, as since the NSA was founded, the director has always been a military officer of three star rank.

Factual error: The whole book is about a computer breaking a very strong code, and that for every code a large enough computer can be built to break it. That's simply not true: The "one time pad" cannot be broken by brute force, only by traditional stealing of the key.

Plot hole: Early on in the book the NSA is described as a top secret agency, an agency very few Americans know exist. However throughout the rest of the book there are many references to groups who openly protest against the NSA, bad widespread publicity, and the majority of Americans being against the agency. If hardly anybody knows about the NSA then how can there be so much open debate about it?

Factual error: At one point, an underground chamber is described as having a 40-by-30 foot video wall at one end, and having been built by excavating 250 metric tons of earth. Assuming the earth to be of average density, the room would be less than 2 meters long.

Continuity: In Chapter 120, the main characters discover what they realize is an 8-by-8 Caesar box code. The first two times we see the letters of this code, the fourth sequence of four letters reads MFHA. The first letter, M, is a typo - it should actually be P. When the letters are grouped in an 8-by-8 grid in Chapter 121, this sequence has now changed to the correct PFHA. The correct letter P gives you the word "responsible"; the incorrect letter M would yield "resmonsible".

Factual error: Towards the end of the book the protagonist is being chased up the Giralda, but manages to escape by pushing his pursuer down the stairs. There are no stairs in the Giralda, however. The inside is ramped.