OPTICAL TRANSMISSION DEVICE AND RECEIVING DEVICE FOR YUEN ENCRYPTION, OPTICAL TRANSMISSION METHOD AND RECEIVING METHOD FOR YUEN ENCRYPTION, AND ENCRYPTED COMMUNICATION SYSTEM

摘要

[Problem] To provide an optical signal configuration method, encryption device, and encryption system whereby it is possible for an authorized communicating party to communicate long-distance with information-theoretic security ensured against a known-plaintext attack. [Solution] By adding a transmission information data sequence randomization device to this Yuen encrypted communications device, which divides transmission information into blocks, appends sequence numbers thereto, randomly switches the order of the blocks with a digitized signal of output of an electrical noise generator, and inputs same into a conventional Yuen encrypted optical transmitter transmission data generator, the relation between a known transmission information data sequence (plaintext) and an optical signal which is outputted from a transmitter is randomized, allowing forcibly making even a circumstance wherein a known-plaintext attack would be possible into a ciphertext-only attack, implementing information-theoretic security against a known-plaintext attack.