Reliability of Information Conversion When Encrypting Graphic Images

The article examines the influence of the initial image parameters on the result of its encryption for different encryption algorithms and modes of their use. Graphic files of the *.ppm format is used as research objects, having various characteristics: color or monochrome image, a graphic or photographic image, large or small resolution, an image of one object or many small ones, the presence of foreign inserts (steganocontainers), the presence of a background in the image, the absence of a background in the image and other. The research methods used are encryption standards DES, AES and GOST R34.12-2015 (Magma and Kuznyechik algorithms), which are implemented in the context of two modes: electronic codebook mode and block chaining mode. It is shown that the original content of graphic information directly affects the level of information mixing when using encryption in ECB mode. To check the quality of encrypted information, NIST tests were used to determine the properties of pseudo-random sequences.