| 摘要 |
A method and apparatus for storing and retrieving program material for subsequent replay is disclosed. In summary, the present invention describes a system and method for storing and retrieving program material for subsequent replay. The method comprises the steps of accepting encrypted access control information and the program material encrypted according to a first encryption key, the access control information including a first encryption key and control data; decrypting the received access control information to produce the first encryption key; decrypting the program material using the first encryption key; re-encrypting the program material using according to a second encryption key; encrypting the second encryption key according to a third encryption key to produce a fourth encryption key; and providing the re-encrypted program material and a fourth encryption key for storage. The apparatus comprises a conditional access module, for accepting encrypted access control information and the program material encrypted according to a first encryption key, the encrypted access control information including the first encryption key and temporally-variant control data, the control access module comprising a first decryption module, for decrypting the access control information to produce the first encryption key; a first encryption module, for encrypting a second encryption key with a third encryption key to produce a fourth encryption key; and a second decryption module for decrypting the fourth encryption key to produce the second encryption key.
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