| 摘要 |
Many different key data items can be prepared even if the memory capacity of a key data setting unit (32) incorporated in a content decryption unit (18).
Partial content data items to be successively read are stored in an accumulation medium (11), encrypted with corresponding key data items. There are provided a key data table which stores the key data items, a read processing section (303a) for reading, from the accumulation medium, the partial content data items, a decryption unit (18) for decrypting the read partial content data items, and a set-key selection section (303b) for reading, from the key data table, a key data item for decrypting a partial content data item to be decrypted, and a key data item for decrypting a partial content data item to be processed next at least, the set-key selection section also setting the read key data items in the decryption unit.
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