A method for service delivery to a client, in which the client selects a service, and establishes a connection with a system server to which it sends an identity associated with the client and an identifier of the service. The system server verifies that the client is authorized to access to the service and that the client is non-emulated. If this is verified, the service is provided to the client. In a preferred embodiment, the service is scrambled content and the system server provides a descrambling key to the client, and instructs a content server to provide the scrambled content to the client. Also claimed are a device, a system, and a system server.