DATA STREAM ENCRYPTION METHOD Russian patent published in 2004 - IPC

FIELD: electrical communications and computer engineering; cryptographic conversion.

SUBSTANCE: proposed method includes generation of encryption key in the form of binary vector; delivery of the latter for initial filling of feedback shift register shaping pseudorandom sequence of binary characters; conversion of data stream into encrypted message, and its transfer over communication line; novelty is that pseudorandom sequence of binary characters is shaped as pseudorandom sequence postamble Fp with characteristic of p = 257 in the form of eight-bit vectors by reading information off eight different places of shift register whose numbers are found by value of encryption key being entered, while skipping time steps of shift register where at least one of generated pseudorandom sequence characters of postamble Fp includes character "0"; data stream is converted into encrypted message by dividing source data stream into blocks in the form of eight-bit binary vectors, and blocks are alternately converted into binary vector using pseudorandom sequence characters of postamble Fp in compliance with chosen linear or nonlinear cryptographic conversions including character addition, multiplication, and exponentiation in preamble Fp.

EFFECT: enhanced attack stability of logical number based on known and selected source texts.

1 cl, 2 dwg