This book offers complete coverage of all aspects of computer security, including users, software, devices, operating systems, networks, law, and ethics. Reflecting rapidly evolving attacks, countermeasures, and computing environments, it introduces up-to-the-minute best practices for authenticating users, preventing malicious code execution, using encryption, protecting privacy, implementing firewalls, detecting intrusions, and more. Cryptography is critical to computer security; it is an essential tool that students and professionals must know, appreciate and understand. But as with most tools, the user does not need to be a maker: using a screwdriver successfully is entirely separate from knowing how to forge the metal from which it is made. This edition will separate the use of cryptography from its underlying mathematical principles.