Cryptography in C and C++

Cryptography in C and C++ mainly focuses on the practical aspects involved in implementing public key cryptography methods, such as the RSA algorithm that was recently released from patent protection. It also gives both a technical overview and an implementation of the Rijndael algorithm that was selected as the Advanced Encryption Standard by the U.S. government. Author Michael Welschenbach avoids complexities by explaining cryptography and its mathematical basis in terms a programmer can easily understand.

This book offers a comprehensive yet relentlessly practical overview of the fundamentals of modern cryptography. It contains a wide-ranging library of code in C and C++, including the RSA algorithm, completed by an extensive Test Suite that proves that the code works correctly. Readers will learn, step by step, how to implement a platform-independent library for the all-important multiprecision arithmetic used in modern cryptography. This is followed by an implementation of the cryptographic algorithms themselves.

The CD-ROM includes all the programs presented in the book, x86 assembler programs for basic arithmetical operations, implementations of the new Rijndael Advanced Encryption Standard algorithm in both C and C++, and more.

User review
Good book with valuable source code
This book is really good for beginners in cryptography. However, the most useful thing in the book is the source code, which can be used for programming your own crypto protocols. I would give this 5/5 rating.

User review
practical guide to software implementation of cryptography
This book offers a practical and relatively easy to read description of implementing cryptography algorithms, especially RSA, in software. Most books in the field are highly mathematical. This book covers all of the necessary mathematics, but also explains how to efficiently implement the mathematics in C. It covers many of the real-life issues in building security software. As a researcher in the field, I found the book very helpful.

User review
Excellent!
Don't even try to do crypto routines in C/C++ without this book.

It will save you a lot of heartache.

Read it!

User review
Good book -- Wrong title
If truth in titling were a crime, someone would be in leg-irons over this one. This book should be entitled, `A Detailed Account of the Construction of a Large-Precision Number Library of the Sort that can be Used for RSA and Similar Cryptographic Systems, with a few Examples.` The book fulfills this latter title exceptionally well.

The great majority of this book is a detailed, step-by-step account of the how the author constructed a C-language big-number library. It treats wrapping the C-libraries with C++ classes as a separate chapter -- nice touch. This treatise is thorough, well-written, and engaging. Nicely done. It is written from a mathematicians perspective, and its mathematical underpinnings may repel some programmers, but they need not fear. In the end the C-code is well-explained.

The only `cryptography` of note is a chapter on implementing RSA with the library. Indeed, the great majority of implementing RSA and similar ciphers is creating the big-number libraries. The RSA chapter is, fortunately, much more than a simple example. It is an excellent treatise of the pitfalls in implementing RSA. That is, RSA is more than a `simple example.` If you are implemeting RSA with any big-number library, this chapter alone is worth the cost of admission.

There is a chapter on AES (Rijndael) cipher, but it is out of place here and an obvious paste-on, probably a last minute, hot-button item required by the publisher. It really has nothing you can't get from the original NIST documents on AES.

I'm willing to believe that the title and AES paste-on are the fault of the publisher, because otherwise Welschenbach did an excellent job -- lots of hard and careful work, well documeted. With a title-change, I'd give it a 5-star.

The question in the end is: Why would you want this book? Apart from general interest, the audiences that come to my mind are those who are constructing such libraries on their own, and those who need to use the software included with the book (on a non-commercial basis -- the software license prohibits commercial use).

User review
a book that takes the abstract and makes it practical
This book will only be appealing to avid crypto fans. The book takes the abstract concept of contemporary algorithms and provides mechanisms for the user to contstruct concrete examples in C & C++ computer code. A rare advanced crypto book that also provides the reader with the mechanisms to explore the various aspects of contemporary advanced crypto ideas in programs. Welschenbach provides the boilerplate code for integrating these highly esoteric functions in C. Invaluable if you have both crypto knowledge and programming acumen.