METHOD AND SYSTEM FOR SECURE PROCESSING A STREAM OF ENCRYPTED DIGITAL AUDIO/VIDEO DATA

摘要

Method and system to prevent control words sharing. The system comprises a receiver capable of processing a digital data stream. The receiver, having a video descrambler device, is coupled to a primary and secondary secure device. The digital data stream comprises video content data scrambled by a first algorithm using a control word, audio content data encrypted with a secret second algorithm using a system key, and encrypted control messages comprising the control word. The primary secure device decrypts the control message and obtains the control word. The video descrambler device uses this control word to descramble the video content data. The secondary secure device comprises a decryption device which decrypts the encrypted audio content data and a watermarking module configured to add a watermark to the decrypted audio content data and return watermarked decrypted audio content data to the receiver.

主权项

1. A method for processing a digital data stream comprising video content data scrambled by a first algorithm using at least one control word, and audio content data encrypted by a second algorithm using a system key, said digital data stream further comprising encrypted control messages containing the at least one control word, the digital data stream being input by a receiver comprising a video descrambler device, the receiver being coupled to a primary secure device and a secondary secure device, the method comprising the steps of:
extracting by the receiver a control message from the digital data stream; transmitting to the primary secure device the extracted control message; receiving a decrypted control word by the receiver from the secondary secure device; descrambling the video content data using the first algorithm and the control word; transmitting to the secondary secure device the encrypted audio content data; receiving the watermarked decrypted audio content data by the receiver from the secondary secure device; and outputting by the receiver the descrambled video content data and the watermarked decrypted audio content data to a display device.