Method and system for protecting video data

• US 20030206636A1
• Filed: 05/02/2002
• Published: 11/06/2003
• Est. Priority Date: 05/02/2002
• Status: Active Grant

• Current Assignee: Pixelworks Incorporated
• Original Assignee: VIXS Systems Incorporated (Pixelworks Incorporated)
• Inventors: Ducharme, Paul, Eng, Steven
• Granted Patent: US 7,120,253 B2
• Time in Patent Office: Days
• US Class Current: 380/277
• CPC Class Codes: H04N 21/2221 being a cable television head-end CATV in broadcast systems H04H20/78
• CPC Class Codes: H04N 21/2343 involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements video transcoding H04N19/40; media packet handling at the source H04L65/762
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/26606 for generating or managing entitlement messages, e.g. Entitlement Control Message [ECM] or Entitlement Management Message [EMM] arrangements for conditional access to broadcast information or to broadcast-related services H04H60/14
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

A key protected data stream and an encryption key are received at a gateway device. The gateway devices unprotects the data stream based upon the encryption key. The unprotected received data is modified by the gateway to generate a modified data. The modified data is protected based upon the encryption key to generate a key protected modified data. The gateway then transmits the key protected modified data to one or more clients along with the encryption key.

Claims

1. A method comprising the steps of:

receiving a first video stream comprising a key protected first video data and an encryption key; and

providing a second video stream comprising a key protected second video data and the encryption key, wherein the second video data is different than the first video data.

2. The method of claim 1 further comprising the step of:

decoding the key protected first video data based upon the encryption key to obtain the first video data.

3. The method of claim 2 further comprising the steps of:

decrypting the encryption key to obtain a control word;

un-protecting the key protected first video data based on the control word to obtain the first video data; and

determining the key protected second video data based on the second video data and the control word.

4. The method of claim 1 further comprising the step of:

providing the first video stream, wherein a client can use the encryption key to decode at least one of the first video stream and the second video stream.

5. The method of claim 1 further comprising the step of:

modifying the first video data to generate the second video data.

6. The method of claim 5, wherein the step of modifying includes the second video data having a lower resolution than the first video data.

7. The method of claim 5, wherein the step of modifying includes the second video data having a lower bit rate than the first video data.

8. The method of claim 1, further comprising the step of:

receiving an Entitlement Control Message (ECM) that includes the encryption key.

9. The method of claim 8, wherein the step that includes providing the encryption key further comprises providing the encryption key by providing the ECM message.

10. The method of claim 8, further comprising the step of:

receiving an Entitlement Management Messages (EMM); and

the step of providing the second video stream includes providing the EMM.

11. The method of claim 1 further comprising the step of:

providing the second video stream using a wireless protocol.

12. The method of claim 1, wherein the step of providing further comprises providing the encryption key in a first packet of information prior to providing the key protected second video data.

13. A system comprising:

an information receiver portion having an input to receive key protected first video information and an encryption key from a content provider, and an output;

a storage portion having an input coupled to the output of the information receiver portion to receive the encryption key, and an output; and

an information provider portion having a first input coupled to the output of the storage portion to access the encryption key, an output to provide a second key protected video information to a client, where the second key protected video information includes the encrypted key.

14. The system of claim 13 wherein the information receiver portion comprises a transport stream demultiplexer.

15. The system of claim 13 wherein the information receiver portion comprises a network interface card to provide an interface to a digital network.

16. The system of claim 15 wherein the network interface card to provides an interface to an Ethernet based network.

17. The system of claim 13 wherein the information provider portion comprises a transport stream multiplexer.

18. The system of claim 17 wherein the information provider further comprises a wireless interface portion to provide the second key protected video to the client over a wireless connection.

19. The system of claim 13 wherein the information provider portion comprises a network interface card to provide an interface to an Ethernet based network.

20. The system of claim 19 wherein the information provider further comprises a wireless interface portion to provide the second key protected video to the client over a wireless connection.

21. The system of claim 13 further comprising:

a decryptor interface port to interface to a decryptor portion that is to receive the decryption key and to provide a control word based on the encryption key; and

a descrambling module having a first input coupled to the decryptor interface port to receive the control word, a second input to receive the key protected first video information, and an output to provide the first video information.

22. The system of claim 21, wherein the decryptor portion comprises a decryption device.

23. The system of claim 13 further comprising:

a video reconstruction portion having a first input coupled to the output of the storage portion to receive a representation of the encryption key, and a second input coupled to the output of the information receiver to receive the key protected first video information, and an output to provide the first video information;

a video stream modifier having a first input coupled to the output of the video reconstruction module to receive the first video information, and an output to provide a second video information that is different than the first video information; and

a video protection portion having a first input coupled to the output of the storage portion to receive the representation of the encryption key, and an output to provide key protected second video information.

24. The system of claim 23, wherein the video reconstruction portion comprises a video descrambler.

25. The system of claim 24, wherein the video protection portion comprises a video scrambler.

26. The system of claim 23, wherein the video reconstruction portion comprises a key decryptor.

27. A system comprising:

a video gateway having a first input to receive a first video stream comprising a key protected first video data and an encryption key, and an output to provide a second video stream comprising a key protected second video data and the encryption key wherein the second video data is different than the first video data and is protected based upon the encryption key; and

a client having an input to receive the protected second video stream and the encryption key and an output to provide video images based upon the second video stream to a display.

28. The system of claim 27, wherein the output of the video gateway is coupled to a wireless transmitter.