This paper represents a developed cryptographic information protection algorithm based on a substitutionpermutation network. We describe the cryptographic transformations used in the developed algorithm. One of the features of the algorithm is the simplicity of its modification with regard to different security levels. The algorithm uses a predeveloped S-box tested against differential and linear cryptanalysis. The S-box is consistent with one of the known standards AES and GOST R 34.12-2015. We provide the findings of an avalanche-effect investigation and statistical properties of ciphertexts. The algorithm actually meets the avalanche-effect criterion even after the first round.

Currently, the Republic of Kazakhstan is developing a new standard for symmetric data encryption. One of the candidates for the role of the standard is the Qamal encryption algorithm developed by the Institute of Information and Computer Technologies (Almaty, Republic of Kazakhstan). The article describes the algorithm. Differential properties of the main operations that make up the Qamal cypher are considered in the questions of stability. We have shown that for a version with a 128-bit data block and the same secret key size for three rounds of encryption it is difficult to find the right pairs of texts with a probability of 2–120, which makes differential cryptanalysis not applicable to the Qamal cypher.