The field of network security and management is constantly undergoing changes in technology and applications. Therefore, there is a need to acquire continuously changing skill set on the part of students. This fully revised and updated text, now in its third edition, discusses in detail important concepts and major developments in network security and management. It discusses security infrastructure and provides a concise survey of the cryptographic algorithms and protocols underlying network security application. In addition, the book also dwells upon hardware and software security, information system security, wireless security and internet banking systems. The book contains 250 questions and answers and a glossary of important terms. It is designed for a one-semester course for undergraduate students of Computer Science, Information Technology, and undergraduate and postgraduate students of computer applications.