DATA HIDING METHOD AND DATA EXTRACTING METHOD

摘要

A method of hiding message information in media information in a frequency space. A high resistance to removal and alteration of hidden message is given. Even when signal processing is executed by using a frequency filter, the hidden message information is continuously maintained effectively. The frequency spectra (f1 and f2) of the medium information (M) and message information (m) are found by frequency-converting the information (m) and the information (M) in order to hide the message information (m) in media information (M). Then an area containing a characteristic frequency component indicating the feature of the message information (m) in a real space is extracted from the frequency spectrum (f2) of the message information (m) as a basic area (B). Then a frequency spectrum (f3) is generated as intermediate information by making n copies of the basic area (B), dispersedly arranging the copies in the frequency space and making the other frequency components zero. Lastly, the message information (m) is hidden in the medium information (M) by executing operation based on the frequency spectrum (f3) and medium information (M).