| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a configuration capable of preventing the perfect reproduction of a content even when the cipher key of an encryption content is leaked. <P>SOLUTION: Patterns 1-k are set, where blocks 1-i being content configuration data are encrypted by different block keys. Block selection is randomly performed in content distribution units, so as to provide to a client, a content constituted of the different block array (pattern sequence) of the blocks 1-i. The block array of the content to be provided to the client is registered as management information. The perfect reproduction of the content is disabled even when a common key (a title key) to be used as the cipher key of the partial content is leaked. Besides, the block array is acquired from an illegal circulation content and collated with the registration information of the management information, thereby to identify a client which is the source of the illegal circulation content. <P>COPYRIGHT: (C)2012,JPO&INPIT |
