Optical transmission device and reception device for yuen encryption, optical transmission method and reception method for yuen encryption, and encrypted communication system

Abstract

A configuration method of an optical signal, an encryption device, and an encryption system makes it possible for a legitimate communicating party to ensure information-theoretic security against a known plain text attack and to communicate long-distance. By adding a transmission information data sequence randomization device to the Yuen encrypted communications device according to the present information, which divides transmission information data into blocks, appends sequence numbers thereto, randomly switches the sequence of the blocks with a digitized signal of output of an electrical noise generator, and inputs same into a transmission data generator of a conventional Yuen encrypted optical transmitter, the relation between a known transmission information data sequence (plain text) and an optical signal which is outputted from the transmitter is randomized, allowing forcibly making even a circumstance wherein a known-plain text attack would be possible into a cipher-text-only attack, realizing information-theoretic security against a known-plain text attack.