CRC Press
ISBN: 0-8493-8523-7
October 1996, 816 pages
By Alfred J. Menezes, Paul C. van Oorschot and Scott A. Vanstone.

The Handbook of Applied Cryptography is one of the best general cryptography references there is. The treatment is much more mathematical than most books on the topic that are suitable as an introduction. The downside is it's much more expensive than, say, Applied Cryptography. However, their publisher has allowed them to put the book up in postscript and pdf on the author's web page* (be sure to read and follow the copyright notice**.)

To give you an idea of how the book is laid out, here is a brief table of contents blatantly stolen from the book's web page.

  1. Overview of Cryptography
  2. Mathematical Background
  3. Number-Theoretic Reference Problems
  4. Public-Key Parameters
  5. Pseudorandom Bits and Sequences
  6. Stream Ciphers
  7. Block Ciphers
  8. Public-Key Encryption
  9. Hash Functions and Data Integrity
  10. Identification and Entity Authentication
  11. Digital Signatures
  12. Key Establishment Protocols
  13. Key Management Techniques
  14. Efficient Implementation
  15. Patents and Standards

* http://cacr.math.uwaterloo.ca/hac/
** http://cacr.math.uwaterloo.ca/hac/about/copyright-notice.html