Method of and apparatus for restricting copy of digital information, and apparatus for recording digital information

摘要

An apparatus for restricting a copy of digital information (20) is provided with: a detecting device (21, 22, 23, 24) for detecting a first watermark, which is buried in the digital information and comprises a first signal generated on the basis of a first rule; and a burying device (25, 26, 27) for burying a second watermark, which comprises a second signal generated on the basis of a second rule and having a structure different from that of the first signal, into the digital information if the first watermark is detected by the detecting device. A recording apparatus (100) is provided with: an inputting device (10) for inputting the digital information; the above mentioned copy restricting apparatus (20); and a recording device (50) for recording the digital information in which the second watermark is buried by said burying device.