METHOD AND DEVICE FOR ELECTRONIC WATERMARK AND RECORDING MEDIUM WITH STORED PROCESSING PROGRAM THEREFOR

摘要

PROBLEM TO BE SOLVED: To prevent a center for embedding electronic watermarks from unauthorized distributing a digital work. SOLUTION: The holder of the digital work inputs the digital work to a holder device 10, enciphers that work with a cryptographic key, while using an enciphering means 13 and transmits the enciphered digital work to a center 20. The center 20 embeds an electronic watermark to the received enciphered digital work and sends the enciphered digital work embedded with that electronic watermark to the holder device 10. The holder device 10 deciphers the received information with the cryptographic key, while using a deciphering means 15 and provides information directly embedding the electronic watermark in the digital work.