Best-selling author and two-time winner of the TEXTY award for the best Computer Science and Engineering text, William Stallings provides a practical survey of both the principles and practice of cryptography and network security. This text, which won the 1999 TAA Award for the best computer science and engineering textbook of the year, has been completely updated to reflect the latest developments in the field. It has also been extensively reorganized to provide the optimal sequence for classroom instruction and self-study.