Patent ID: 7200868

Claim:
A method of controlling access to an encrypted instance of service, which was encrypted by a first key, the method implemented in a receiver in a subscriber television system, the method comprising the steps of: (a) duplicating the first key; (b) encrypting the duplicate first key with a second key; (c) transmitting from the receiver the encrypted duplicate first key; (d) encrypting the first key using a public key of a private key-public key pair belonging to the receiver, thereby converting the first key into an encrypted first key; (e) associating a key validator with the encrypted first key, wherein the key validator includes a time indicator that indicates whether the encrypted first key is valid; (f) determining whether the encrypted first key is valid; (g) receiving at the receiver a second key validator that indicates the validity of the receiver to use the first key to decrypt the encrypted services; (h) responsive to the encrypted first key being valid, decrypting the encrypted first key thereby recovering the first key; and (i) responsive to the second key validator indicating the encrypted first key is valid, decrypting the encrypted service instance using the recovered first key.