METHOD FOR BINARY DATA CRYPTOGRAPHIC CONVERSION Russian patent published in 2004 - IPC

FIELD: electrical communications and converter engineering. SUBSTANCE: proposed method can be used in communication systems, computing and data-processing systems during data exchange and includes following procedures: input data are divided into fixed-length blocks and coded by means of arithmetic operation with cryptographic pseudorandom functions F1, F2, and F3 dependent of mentioned key sequence; data are entered during each step for arithmetic coding in character-by-character manner and coded with aid of F2 conversion implementing character table and occurrence probability interval table of F3 conversion implementing characters; character table is updated by interchanging characters in character table; then occurrence probability intervals are exchanged in mentioned table, whereupon converted input data are transferred to input data block. EFFECT: enhanced reliability of protection against cryptographic analysis and unauthorized data decoding. 3 cl, 1 dwg