Covers the concepts of information assurance, explicit and implicit policy design, use of basic computer security mechanisms, authentication, access control, policy types. Topics include: Design and use of basic network security mechanisms, asset identification and valuation, determining threats to assets and their vulnerabilities, prioritizing and selecting countermeasures, implementing and deploying countermeasures, and continuing maintenance and assessment of security mechanisms, Classical cryptography (Shift cipher, Affine cipher, Vigenere cipher, Hill cipher, and Permutation (transposition) cipher. Introduces firewalls, network intrusion detection, Viruses, Worms, Trojan horses, and other forms of malicious code.