| 摘要 |
PROBLEM TO BE SOLVED: To manage video or audio information in generation by decoding encrypted information and reproducing the decoded information even when the video or audio information in an encrypted state is recorded/reproduced as it is. SOLUTION: In the care of decoding encryption, an electronic mark is updated by an encryption decoding means that receives video or audio information encrypted and coded by using copy generation management information to at least identify disabled copy and one-copying available state and decodes the information by using the copy generation management information to decode the original coded video or audio information. In the case of decoding, when the copy generation management information used by an encryption decoding circuit 10 differs from the copy generation management information depicted by electronic watermark information detected by an electronic watermark detection circuit 20, an electronic watermark update circuit 30 updates the electronic watermark information so that both the copy generation management information sets are matched with each other. |
