The fifth edition of Computer Security: Principles and Practice captures the continued innovations, improvements, and challenges in computer and network security while maintaining its comprehensive coverage of basic principles. In addition to covering new topics such as multi-factor authentication, supply-chain and business email compromise attacks, and recent security incidents such as the SolarWinds cyberattack, it includes updated lists such as the top 25 most dangerous software errors and NIST security controls. Intended for both students and professionals, it is designed to support various certifications and curricula, including the Certified Information Systems Security Professional (CISSP), National Centers of Academic Excellence in Cybersecurity (NCAE-C), and the ACM/IEEE Cybersecurity Curricula 2017. An extensive suite of resources for instructors and students provides hands-on experience to reinforce concepts. Hacking Exercises help students gain an understanding of issues in intrusion detection and prevention; Laboratory Exercises involve implementing security functions and applications; and Firewall Projects include a portable network firewall visualization simulator and related exercises that teach the fundamentals of firewalls. The text is supported by real-world Case Studies, which set theory into context, and Review Questions and Problems, which help students revise the topics covered in each chapter.