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.