Introduction - Security services, security services, security mechanisms Finite fields - group, ring, fields, modular arithmetic, The Euclidean algorithm. Symmetric Cipher Model, Cryptography, Cryptanalysis and Attacks; Substitution and Transposition techniques. (Chapter - 1) 2. Stream ciphers and block ciphers, Block Cipher structure, Data Encryption standard (DES) with example, strength of DES, Design principles of block cipher, AES with structure, its transformation functions, key expansion, example and implementation. (Chapter - 2) 3. Multiple encryption and triple DES, Electronic Code Book, Cipher Block Chaining Mode, Cipher Feedback mode, Output Feedback mode, Counter mode. (Chapter - 3) 4. Public Key Cryptosystems with Applications, Requirements and Cryptanalysis, RSA algorithm, its computational aspects and security, Diffie-Hillman Key Exchange algorithm, Man-in-Middle attack. (Chapter - 4) 5. Cryptographic Hash Functions, their applications, Simple hash functions, its requirements and security, Hash functions based on Cipher Block Chaining, Secure Hash Algorithm (SHA). (Chapter - 5) 6. Message Authentication Codes, its requirements and security, MACs based on Hash Functions, Macs based on Block Ciphers. (Chapter - 6) 7. Digital Signature, its properties, requirements and security, various digital signature schemes (Elgamal and Schnorr), NIST digital Signature algorithm. (Chapter - 7) 8. Key management and distribution, symmetric key distribution using symmetric and asymmetric encryptions, distribution of public keys, X.509 certificates, Public key infrastructure. (Chapter - 8) 9. Remote user authentication with symmetric and asymmetric encryption, Kerberos. (Chapter - 9) 10. Web Security threats and approaches, SSL architecture and protocol, Transport layer security, HTTPS and SSH. (Chapter - 10)