Tutorial contains general information: basics of cryptology, cryptography and cryptographic analysis; traditionally historical substitution and permutation ciphers; block and compound ciphers and attacks on them; stream ciphers and pseudo-random number generators; cryptographic encryption and conversion standards; block symmetric cryptographic algorithms; principles of building symmetric and asymmetric cryptographic encryption systems, which are used to ensure data confidentiality in information and telecommunication systems, as well as examples with solutions, control tasks with answers.