Patent ID: 7970138

Claim:
A method for providing conditional access to a media program of a plurality of media programs, comprising the steps of: transmitting media information encrypted according to a control word (CW) from a headend to a receiver station; transmitting an entitlement management message (EMM) comprising entitlement management information (EMI) from the headend to the receiver station, the EMI comprising a service bitmap indicating entitlements to a plurality of programs; generating a processed second key (K 2 ′) from a second key (K 2 ), the service bitmap, and a key (K); transmitting the processed second key (K 2 ′) to the receiver station; and transmitting an entitlement control message (ECM) comprising entitlement control information (ECI) to the receiver station, the entitlement control information including the control word (CW) encrypted according to the key (K) and a service identifier having an index to an element of the service bitmap; wherein the receiver station regenerates the key (K) and the second key (K 2 ) from the processed second key (K 2 ′) and the service bitmap, and regenerates the control word (CW) from the regenerated key (K) and the regenerated second key (K 2 ).