| 摘要 |
PROBLEM TO BE SOLVED: To reproduce contents with a digital watermark embedded therein while removing the digital watermark when reproducing the contents by an authorized user and an allowable content reproducing apparatus. SOLUTION: A private cryptographic key is written from a user to a flash ROM 221 of a content reproducing apparatus 22, the cryptographic key written in the content reproducing apparatus 22 and a user ID managing the content reproducing apparatus 22 are relatively registered in a client database 11 of a content providing server 1 via the inherent apparatus information of the content reproducing apparatus 22. When a content request from the user is received, the cryptographic key corresponding to the content reproducing apparatus 22 of a distribution destination is used to embed digital watermark information in contents provided by a digital watermark information embedding means 13 and the contents are then provided. At the side of the content reproducing apparatus 22, on the other hand, processing for separating the digital watermark from the acquired contents is performed and when it is properly separated, the digital watermark removed contents are outputted. COPYRIGHT: (C)2005,JPO&NCIPI
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