The ouline of the course will be something like this: Monday: Introduction, Classical Systems, Block Ciphers, The Principle of Public Key Cryptography, Mathematical Prerequisites. Tuesday: Discrete Logarithm Based Systems, the Diffie-Hellman Key-Exchange System and some variations, How to Take Discrete Logarithm in particular the Index-Calculus Method. The logarithm system over elliptic curves. Wednesday: RSA, the system and its security, some factorization algorithms, some unsafe modes for RSA, how to generate large prime numbers.