This exciting new resource provides a comprehensive overview of the field of cryptography and the current state of the art. It delivers an overview about cryptography as a field of study and the various unkeyed, secret key, and public key cryptosystems that are available, and it then delves more deeply into the technical details of the systems. It introduces, discusses, and puts into perspective the cryptographic technologies and techniques, mechanisms, and systems that are available today. Random generators and random functions are discussed, as well as one-way functions and cryptography hash functions. Pseudorandom generators and their functions are presented and described. Symmetric encryption is explored, and message authentical and authenticated encryption are introduced. Readers are given overview of discrete mathematics, probability theory and complexity theory. Key establishment is explained. Asymmetric encryption and digital signatures are also identified. Written by an expert in the field, this book provides ideas and concepts that are beneficial to novice as well as experienced practitioners.