To provide a data transmitting apparatus and the like capable of enhancing error detection accuracy without increasing a bandwidth unnecessarily used for the error detection performed on encrypted data and minimizing deterioration in sound quality of the data by effectively reducing noises in the transmission of the data through networks for cars and the like even though the data transmitting apparatus has been simply structured. The present invention makes it possible to perform error detection on audio data according to the sizes of encrypted blocks or packets using simple error check codes embedded in the audio data, or to perform error detection using a variation sequence of attribute information to be transmitted together with the audio data. In this case, output of the sound resulting from the audio data having an error is stopped.