METHOD AND SYSTEM FOR SECURE PROCESSING A STREAM OF ENCRYPTED DIGITAL AUDIO/VIDEO DATA
First Claim
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.
1 Assignment
0 Petitions
Accused Products
Abstract
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.
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Citations
26 Claims
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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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system for processing a digital data stream, the system comprising:
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a receiver having a video descrambler device, the receiver being coupled to a primary secure device and to a secondary secure device, the digital data stream comprising video content data scrambled by a first algorithm using a control word, audio content data encrypted by a second algorithm using a system key and related encrypted control messages comprising the control word, wherein; the receiver is configured to receive the digital data stream, extract a control message from said digital data stream, and transmit to the primary secure device the extracted control message; the primary secure device is configured to decrypt the control message, obtain the control word from the control message, and transmit the control word to the video descrambler device of the receiver; the secondary secure device is configured to receive the encrypted audio content data from the receiver and comprises a decryption device configured to decrypt the audio content data using the second algorithm and the system key previously implemented in the secondary secure device, and a watermarking module configured to add a watermark to the decrypted audio content data and return the watermarked decrypted audio content data to the receiver; the receiver being further configured to output to a display device the descrambled video content data and the watermarked decrypted audio content data provided by the secondary secure device. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23-24. -24. (canceled)
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25. A conditional access module configured to be locally connected to a receiver, the receiver being configured to receive a digital data stream comprising video content data scrambled by a first algorithm using a control word, audio content data encrypted by a second algorithm using a system key and related encrypted control messages comprising the control word, and to extract a control message from said digital data stream, the conditional access module comprising:
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a primary secure device configured to decrypt the control message, obtain the control word from the control message, and to transmit the control word to a video descrambler device included in the receiver; and a secondary secure device configured to receive the encrypted audio content data from the receiver, the secondary secure device comprising a decryption device configured to decrypt the audio content data with the second algorithm by using the system key and a watermarking module configured to add a watermark to the decrypted audio content data and to return the watermarked decrypted audio content data to the receiver, the receiver being further configured to output to a display device the descrambled video content data and the watermarked decrypted audio content data. - View Dependent Claims (26)
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Specification