METHOD FOR CIPHERING BINARY DATA BLOCKS Russian patent published in 1999 - IPC

FIELD: electrical communications and computer engineering. SUBSTANCE: method involves generation of ciphering keys in the form of combination of sub-keys, division of data block into N 2 sub-blocks, and their sequential conversion by executing double-point operations with sub-block and sub-key. Novelty is that prior to executing double-point operation with i-th sub- block and sub-key the latter undergoes substitution operation depending on i-th sub-block. Novelty is also that substitution operation depending on ciphering key is used as substitution operation depending on i-th sub-block executed with substitution operation sub-key. EFFECT: improved ciphering speed in software implementation. 2 cl, 1 dwg