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Recording device, recording medium, and content protection system

  • US 7,889,863 B2
  • Filed: 03/22/2005
  • Issued: 02/15/2011
  • Est. Priority Date: 04/21/2004
  • Status: Expired due to Fees
First Claim
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1. A recording apparatus for transferring a usage right of a content to an external recording medium while protecting a copyright of the content, comprising:

  • a storage unit operable to store i) a first encrypted content generated by encrypting the content, (ii) a second encrypted content generated by performing an irreversible compression to convert the content thereby obtaining a converted content, and by encrypting the converted content, and (iii) a content key for decryption of the first and second encrypted contents;

    a key transfer unit operable to write the content key to the external recording medium, and erase the content key stored in the storage unit; and

    a content transfer unit operable, after the content key has been erased, to write the second encrypted content to the external recording medium, and erase the second encrypted content from the storage unit,wherein the key transfer unit includes;

    a writing subunit operable to write the content key to the external recording medium;

    an erasing subunit operable to erase the content key stored in the storage unit;

    a reading subunit operable to read the content key from the storage unit; and

    a prohibiting subunit operable, after the content key has been read, to prohibit use of the content key stored in the storage unit,wherein the writing subunit performs the writing after the prohibiting subunit has performed the prohibiting,wherein the content key is in association with usability information indicating that the content key can be used, andwherein the prohibiting subunit rewrites the usability information to use-prohibited information indicating that use of the content key is prohibited.

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