How to Read this Book
Practical Cryptography is more a narrative than a reference. It follows the design of a cryptographic system from the specific algorithm choices, outwards through concentric rings to the infrastructure required to make it work. We discuss a single cryptographic problem—one of establishing a means for two people to communicate securely—that's at the heart of almost every cryptographic application. By focusing on one problem and one design philosophy for solving that problem, it is our belief that we can teach more about the realities of cryptographic engineering.
We think cryptography is just about the most fun you can have with mathematics. We've tried to imbue this book with that feeling of fun, and we hope you enjoy the results. Thanks for coming along on our ride.
Niels Ferguson
Bruce Schneier
January 2003