UNIT - I Security Concepts : Introduction, The need for security, Security approaches, Principles of security, Types of Security attacks, Security services, Security Mechanisms, A model for Network Security Cryptography Concepts and Techniques : Introduction, plain text and cipher text, substitution techniques, transposition techniques, encryption and decryption, symmetric and asymmetric key cryptography, steganography, key range and key size, possible types of attacks. (Chapter-1) UNIT - II Symmetric key Ciphers : Block Cipher principles, DES, AES, Blowfish, RC5, IDEA, Block cipher operation, Stream ciphers, RC4. Asymmetric key Ciphers : Principles of public key cryptosystems, RSA algorithm, Elgamal Cryptography, Diffie-Hellman Key Exchange, Knapsack Algorithm. (Chapter-2) UNIT - III Cryptographic Hash Functions : Message Authentication, Secure Hash Algorithm (SHA-512), Message authentication codes : Authentication requirements, HMAC, CMAC, Digital signatures, Elgamal Digital Signature Scheme. Key Management and Distribution : Symmetric Key Distribution Using Symmetric and Asymmetric Encryption, Distribution of Public Keys, Kerberos, X.509 Authentication Service, Public - Key Infrastructure (Chapter-3) UNIT - IV Transport-level Security : Web security considerations, Secure Socket Layer and Transport Layer Security, HTTPS, Secure Shell (SSH) Wireless Network Security : Wireless Security, Mobile Device Security, IEEE 802.11 Wireless LAN, IEEE 802.11i Wireless LAN Security (Chapter-4) UNIT - V E-Mail Security : Pretty Good Privacy, S/MIME IP Security : IP Security overview, IP Security architecture, Authentication Header, Encapsulating security payload, Combining security associations, Internet Key Exchange. Case Studies on Cryptography and security : Secure Multiparty Calculation, Virtual Elections, Single sign On, Secure Inter-branch Payment Transactions, Cross site Scripting Vulnerability. (Chapter-5)