To those unfamiliar with cryptography and network security, this book serves as a primer. Due to the nature of cryptography, even rudimentary testing might reveal a security flaw in the system. Network security is enforced via the use of cryptographic algorithms and certain protocols, both of which are thoroughly covered in this book. Cryptography, Network Security Applications, Security Systems and System Security make up the book’s four sections. The basics of cryptography and network security are explained with many illustrations and examples throughout the book. Because of progress in cryptography and network security, more accessible and useful tools for enforcing network security have become available. This book covers the fundamentals of cryptography and network security as well as their practical applications. Initially, an introduction and overview of cryptography and network security technologies are presented, with a focus on the fundamental concerns that need to be solved by a network security capability. Then, actual, functioning network security applications from the real world are examined.