Patent ID: 7992211
Filing Date: 2011-08-02
Classification: G06F,H04N

Abstract:
1. A method of authorising conditional access to an encrypted digital data product, including storing at least one set of entitlements in a secure device, each entitlement including a product identifier and expiry information; receiving entitlement control messages from a decoder system including a device for decrypting encrypted digital data products using control words, each entitlement control message including a product identifier; in a first mode, returning at least one control word in response to an entitlement control message including a product identifier if the product identifier corresponds to a product identifier in a stored entitlement including expiry information indicating the entitlement to be valid; setting a counter to an initial value to commence operation in a second mode upon receiving an entitlement control message including a product identifier corresponding to a product identifier in a stored entitlement that includes expiry information indicating that the entitlement is expired; and in the second mode, progressively adjusting the counter to a pre-determined value and returning at least one control word in response also to entitlement control messages including a product identifier if the product identifier corresponds to a product identifier in a stored entitlement including expiry information indicating that the entitlement is expired and if the counter is at a value between the initial value and the pre-determined value.