Patent ID: 7477744

Claim:
A device for selectively supplying access to a service that is encrypted using a control word, the device comprising: a receiving module for receiving the service that is encrypted using the control word, the receiving module operable to receive an entitlement control message (ECM) comprising authorization data and a specifier of a validity period of the authorization data; a decrypting module coupled to the receiving module, the decrypting module for decrypting the service using the control word; a timer for providing a time used to compare the time to a specifier of a validity period of the authorization data; a conditional access module coupled to the decrypting module and the timer, the conditional access module operable to obtain the authorization data and the specifier of the validity period of the authorization data from the ECM, the conditional access module operable to provide the control word to the decrypting module in dependence on a verification of the authorization data and on a determination of the time provided by the timer being within the validity period; an ECM transcoding module coupled to the conditional access module, the ECM transcoding module operable to generate, from the ECM, a device-specific ECM, the device-specific ECM associated with the received service, the device-specific ECM including the authorization data, wherein the device-specific ECM includes a first identifier for a specific device where the receiving module is located; a writing module coupled to receiving module and to the ECM transcoding module, the writing module operable to store the received service, and to store the generated device-specific ECM associated with the received service; the conditional access module operable to obtain, from the writing module, the stored received service and the stored device-specific ECM associated with the received, to compare a second identifier for the specific device with the first identifier from the device-specific ECM, and to provide the authorization data from the device specific ECM to the decrypting module for decrypting the received service only if the first identifier matches the second identifier.