DATA BLOCK ITERATIVE CIPHERING TECHNIQUE Russian patent published in 1999 - IPC

FIELD: electrical communications and computer engineering. SUBSTANCE: ciphering technique includes shaping of secret key, division of data block into two sub-blocks, and execution of R 2 ciphering rounds involving generation of binary vector for first sub-block, conversion of binary vector, and superposition of converted binary vector by means of addition operation onto second sub-block. Novelty is that control code is additionally produced and second sub-block is converted by means of two controlled exchange operations depending on control code value; one of them is executed before superposing binary vector onto second sub-block and other operation, after binary vector is superposed onto second sub-block. Novelty is also that control code is generated according to secret key. Still other novelty is that control code is generated according to secret key and value of one of sub-blocks. EFFECT: reduced number of ciphering rounds which increases ciphering speed. 3 cl, 3 dwg