A smart choice for both novice and experienced professionals looking to broaden their knowledge of contemporary cryptography, this newly revised edition of an Artech House classic puts all aspects of this important topic into perspective. Delivering an accurate introduction to the current state-of-the-art in modern cryptography, this book offers an in-depth understanding of essential tools and applications to help professionals with their daily work. The second edition has been reorganized and expanded, providing mathematical fundamentals and important cryptography principles in the appropriate appendixes, rather than summarized at the beginning of the book. Now readers find all the details they need to fully master the material in the relevant sections. Covering unkeyed, secret key, and public key cryptosystems, this authoritative reference provides solid working knowledge of the latest and most critical concepts, techniques, and systems in contemporary cryptography.