Security Concepts and Definitions (Risks, Threats, Security Policy, Safeguards, Services) - Four Layer Security Model - Symmetric Key Cryptographic Techniques - Key Management Techniques for Symmetric Key Cryptography - Asymmetric Key Cryptographic Techniques - Digital Signature - Key Management Techniques for Asymmetric Key Cryptography - PKI – Practical Security Protocols - Security in Mobile Networks – Security in Wireless Networks.