摘要 |
A data communication apparatus improves security against eavesdropping for secret communication by using Y-00 protocol. A multi-level code generation section generates, based on key information, a multi-level code sequence in which a signal level changes so as to be approximately random numbers. A level conversion section irreversibly converts the multi-level code sequence such that a converted multi-level code sequence does not constitute a mapping of the multi-level code sequence. A multi-level processing section generates a multi-level signal having a plurality of levels each corresponding to a combination between the information data and the multi-level code sequence. A modulator section modulates a multi-level signal in a predetermined modulation method and outputs a modulated signal.
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