Basic terms, secrecy theory, perfect cipher. Symmetric cryptosystems - stream ciphers, block ciphers, standards of symmetric ciphers, key management and distribution. Asymmetric cryptosystems - RSA, DL and EC types of cryptosystems, key agreement, standards of asymetric cryptosystems. Hash and other auxiliary cryptographic functions, data integrity, authentication, digital signatures. Public key infrastructure, modern cryptographic services. Electronic voting, sharing of secret information. Quantum cryptography. Introduction to the cryptoanalysis, attacks on cryptosystems and their defence.