Introduction. Overview on Modern Cryptography. Introduction to Number Theory. Probability and Information Theory. Classical Cryptosystems. Cryptanalysis of Classical Ciphers. Shannons Theory. Shannons Theory (Contd...1). Shannons Theory (Contd...2). Symmetric Key Ciphers. Block Cipher Standards (DES). Block Cipher Standards (AES). Block Cipher Standards (AES) (Contd.). Linear Cryptanalysis. Differential Cryptanalysis. Few other Cryptanalytic Techniques. Overview on S-Box Design Principles. Modes of Operation of Block Ciphers. Stream Ciphers. Stream Ciphers (Contd...1). Stream Ciphers (Contd...2). Pseudorandomness. Cryptographic Hash Functions. Cryptographic Hash Functions (Contd...1). Cryptographic Hash Functions (Contd...2). Message Authentication Codes. More Number Theoretic Results. The RSA Cryptosystem. Primality Testing. Factoring Algorithms. Some Comments on the Security of RSA. Discrete Logarithm Problem (DLP). The Diffie-Hellman Problem and Security of ElGamal Systems. An Introduction to Elliptic Curve Cryptography. Application of Elliptic Curves to Cryptography. Implementation of Elliptic Curve Cryptography. Secret Sharing Schemes. A Tutorial on Network Protocols. System Security. Firewalls and Intrusion Detection Systems. Side Channel Analysis of Cryptographic Implementations.