Principles of computer systems and network security. Topics include network attacks and defenses, botuet, malware, social engineering attacks, privacy, and digital rights management. Techniques for achieving security in multi-user computer systems and distributed computer systems; cryptography: secret-key, public-key, digital signatures; authentication and identification schemes; intrusion detection: viruses; firewalls; and risk assessment. Prerequisite: ITS 20263 Introduction to Networking.