Encryption and decryption-What is cryptography? –Conventional cryptography -Public key cryptography- How PGP works - Keys- Digital signatures - Digital certificates- Validity and trust - Certificate Revocation - What is a passphrase? - Key splitting - Technical details

The OSI Security Architecture– Security Attacks – Security Services – Security Mechanisms – A Model for Network Security - Classical Encryption Techniques– Symmetric Cipher Model – Substitution Techniques - Transposition Techniques – Rotor Machines - Steganography

Block Cipher Principles – The Data Encryption Standard - The Strength of DES –Advanced Encryption Standard (AES) – Evaluation Criteria for AES – The AES Cipher – Multiple Encryption and Triple DES – Block Cipher Modes of Operation – Stream Ciphers and RC4- modular Arithmetic and Euclidean Algorithm

Placement of Encryption Function – Traffic Confidentiality – Key Distribution – Public key Cryptography and RSA– Principles of Public Key Cryptosystems – The RSA Algorithm- Basic prime numbers and Discrete Logarithms -Key Management – Diffie Hellman Key Exchange.

Authentication Functions – Message Authentication Codes (MAC’s) Functions– Security of Hash Functions and MAC’s Digital Signatures and Authentication Protocols – Digital Signatures – Digital Signature Standard.