A refresher on the basics and a guide to doing cryptography with Java.
For an excellent explanation of cryptography, including some history, you can't do better than the popular Code Book by Simon Singh.
This book does briefly describe the concepts involved in cryptography, but quickly moves on to explaining the relevant APIs in Java, giving lots of code examples. I'm not looking for the security features of the Java platform, but I am looking for information about how to encrypt data on disc, secure network connections, generate public and private keys, and so on... and that is the topic of this book.
My rating: Good