Computer security refers to the protection of computers from any theft or damage to their software, hardware and data. It is also concerned with safeguarding computer systems from any disruption or misdirection of the services that they provide. Some of the threats to computer security can be classified as backdoor, denial-of-service attacks, phishing, spoofing and direct-access attacks, among many others. Computer security is becoming increasingly important due to the increased reliance on computer technology, Internet, wireless networks and smart devices. The countermeasures that can be employed for the management of such attacks are security by design, secure coding, security architecture, hardware protection mechanisms, etc. This book aims to shed light on some of the unexplored aspects of computer security. Most of the topics introduced herein cover new techniques and applications of computer security. This textbook is an essential guide for students who wish to develop a comprehensive understanding of this field.