Patent ID: 7801300

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 approximate random numbers; a multi-level processing section for combining the multi-level code sequence and the information data, and generating a multi-level signal having a plurality of levels corresponding to a combination of the multi-level code sequence and the information data; and a modulator section for treating the multi-level signal with predetermined modulation processing and generating a modulated signal, wherein the multi-level code generation section generates a bit stream based on the predetermined key information, the bit stream being a binary pseudo-random number, wherein the multi-level code generation section obtains a modified bit stream by regularly or irregularly selecting, deleting, or inversing a bit of the bit stream by using a predetermined method, and wherein the multi-level code generation section generates the multi-level code sequence based on the modified bit stream.