Patent ID: 7907670

Claim:
A data transmitting apparatus for encrypting information data by using predetermined key information and performing secret communication with a receiving apparatus, the data transmitting apparatus comprising: a multi-level code generation section for generating, based on the predetermined key information, a multi-level code sequence in which a signal level changes so as to be approximately random numbers; and a multi-level signal modulator section for generating a signal having a plurality of signal levels in accordance with the information data and the multi-level code sequence, modulating the generated signal in a predetermined modulation method, and outputting a modulated signal, wherein the multi-level signal modulator section divides the signal having a plurality of levels each corresponding to a combination of the information data and the multi-level code sequence into a plurality of groups, and causes a plurality of levels included in each of the plurality of groups to be allocated to one level in an overlapped manner so as to generate the signal having the plurality of signal levels.