Patent ID: 7912215

Claim:
A data transmitting apparatus for performing cipher communication, the data transmitting apparatus comprising: a multi-level code generation section for generating a multi-level code sequence in which a signal level changes in accordance with a random number sequence determined based on predetermined key information; a combining section for combining accompanying data to the multi-level code sequence with predetermined frequency and generating a combined multi-level signal; an error-correction encoding section for adding an error-correction code to information data, in accordance with predetermined error correction encoding processing, and outputting error-correction encoded information data; a multi-level processing section for combining the combined multi-level signal and the error-correction encoded information data in accordance with predetermined processing, and generating a multi-level signal having a level uniquely corresponding to a combination of levels of both combined signals represented by the combined multi-level signal and the error-correction encoded information data; and a modulator section for generating a modulated signal, in a predetermined modulation method, based on the multi-level signal.