I recommend the following book on data encryption:
Applied Cryptography:
Protocols, Algorithms and Source Code in C
Second Edition
Bruce Schneier
ISBN 0-471-11709-9
$43.96 at Amazon.com, $43.95 at FatBrain.com
Excellent book. The writer's style in explaining cryptography is quite
effective. I highly recommend it, as does one of my friends that provides
NIS-certified cryptographic and security analysis for a living.
Rick Gilligan
Senior Software Specialist
Computer And Software Enterprises, Inc.