| 摘要 |
<p>A content reading apparatus only permits the use of contents such as images, music, and the like within a permitted usage period. In a recording medium having an authentication function, secure data that includes a decryption key and a remaining usage period is recorded in a protected area, and an encrypted content corresponding to the secure data is recorded in a user area. A decrypting of the encrypted content by a decryption unit, and an outputting of the decrypted content by an output unit to a user is only permitted for the duration that the usage rights judgment unit judges the remaining usage period to be greater than zero. The remaining usage period is updated by the usage rights judgment unit in accordance with a usage period of the content by the user and rewritten back into the protected area.</p> |
