| 摘要 |
<p>The invention relates to a broadcasting and receiving system and to a system for conditional access thereto. Said invention makes it possible to retransmit a content protected by a provider in a computer network and to preserve the subscriber control by the content provider. The inventive digital media system in a computer network comprises a set of servers which are used for adapting the provider content flows and assigning IP addresses of the computer system thereto and which are accessible via a set of network terminals (STB or personal computers) containing a content player (audio, video, game), a descrambler (decoder) and a content request module connected to servers, which are used for controlling a subscriber access to a local computer network, and to a validator server which provides session keys required for protecting control words of the provider content. The session keys and flow adapting servers of a controllable computer system are used for encoding control words which protect the provider content and afterwards are introduced into control right messages of a content flow and the access control of the network terminals of the subscribers to the IP addresses assigned to the adapted provider content flows are organised by control and configuration means of the controllable computer system. The reports on the access of the subscribers of a controllable computer system to the IP addresses of provider content flows are analysed by the access control server by comparing them with the messages of the validator computer. When the messages of the server validator about the authorised access of a subscriber to the content, which is requested by said subscriber according to the IP address translation of the provider content, are absent, the access control server denies the access. The access is initiated by means of the message exchange procedures between the access control server, network terminal and the validator server, and the successfully authorised access is used for transmitting the IP address of the content flow selected by the subscriber and for forming a protected communications channel between the network terminal and the server validator. The procedure for reproducing the contemn flow to the network terminal consists in receiving by the terminal the content flow on the IP address thereof, in demultiplexing a right control message therefrom, in decoding control words by means of a session key, in descrembling the content data by means of the control wards and in reproducing them by means of a player. The actual session keys are received by the network terminal upon requests via a protected communications channel in the messages of the validator server. The control of the content provider rights consists, in this case, in that the flow reproduction can be stopped by the computer network operator by denying the access of a given network terminal to the content IP address in the controllable computer system on a subscriber port and on the initiative of a validator server by the failure thereof to provide a session key requested by the terminal. The important advantage of said method consists in the possibility of paying for the provided content directly to the provider thereof by using the prepaid PIN-code cards issued by said provider.</p> |
