algorithms

This is a fairly strong book on crypto, with heavy detail on the math involved. The upside is that the second chapter is devoted to most of the important mathematical theory you'll need to understand for the rest of the book. The downside? That chapter tries to cover just about the same breadth of information as a semester long course in Number Theory.

If you don't have a ton of mathematical background and are scared of having to take a crash course in number theory, or are looking for a higher level view of things, I'd suggest something more along the lines of Bruce Schneier's 'Applied Cryptography' (ASIN 0471117099). If you have some mathematical background, but want to get into things in detail, this is probably for you.

If you're not sure whether you'll like the book, you should definitely take a look at it. While Amazon currently doesn't have sample pages, if you do a Web Search on "Handbook of Applied Cryptography", you can find Sample Chapters hosted online to give you a good feel for the book's style.

A thorough coverage of topics in cryptography is only one of many features which make this book invaluable to computer scientists. While not intended to be a textbook, this handbook includes enough background information to be of use to those with minimal theoretical computer science knowledge. The chapter organization is logical and very modular so that after reading the introductory chapters, one can skip ahead to the chapters of interest with little difficulty.
The second chapter provides a concise review of probability theory, information theory, complexity theory, and number theory. This chapter would be helpful to anyone in computer science who already has some discrete math background. For readers with no discrete math background I would recommend first reading "Discrete Mathematics and Its Applications" by Kenneth Rosen, the editor of the series this book belongs to.
The coverage of number-theoretic problems in chapter 3 is very easy to follow and provides a handy reference to the average case performance of the best known algorithms for each.
The next few chapters are very math-intensive and outline the most common encryption algorithms and standards with examples. The chapter on block ciphers includes a section on classical ciphers and cryptanalysis which, as a sidenote, might be of interest to students of linguistics.
The later chapters present protocols for authentication, digital signing, and key management which build on the algorithms of the previous chapters, but can be understood independently.
One of the final chapters presents methods of effecient computation which again would be useful to anyone in computer science, not just those who are interested in cryptography.
Overall, the development of the topics in the book is complete (although by no means rigorous) and concise, including examples only where necessary. I highly recommend this book to students who want to learn more about cryptography, anyone whose job requires some knowledge of standards for authentication, digital signing, etc., such as internet security, and any computer scientist who has an academic interest in algorithms and their applications.

This very detailed work is not for the light hearted. It's an in depth look at the mathmatics behind cryptography. If you're looking for a book to help you program then look for Applied Cryptography by Bruce the crypto king instead. If you're looking for something to help you learn cryptoanalysis and how to break codes then this is the first step.