Encryption scheme for streamed multimedia content protected by rights management system

• US 8,325,916 B2
• Filed: 02/08/2010
• Issued: 12/04/2012
• Est. Priority Date: 05/27/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Oliveira, Eduardo P., Dunbar, Geoffrey, Alkove, James M.
• Primary Examiner(s): POWERS, WILLIAM S
• Application Number:
  US12/702,148
• Publication Number:
  US 20100138647A1
• Time in Patent Office: 1,030 Days
• Field of Search: None
• US Class Current: 380/200
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/835 Generation of protective data, e.g. certificates protecting software against unauthorised usage in a vending or licensing environment G06F21/10
• CPC Class Codes: H04N 21/8456 by decomposing the content in the time domain, e.g. in time segments
• 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 stream of content has multiple sub-streams, where each sub-stream comprises a part of the content and is divisible into logical blocks bounded by intrinsic partitions. For each sub-stream, a specification of the logical blocks bounded by the intrinsic partitions is defined and the sub-stream is divided into the logical blocks bounded by the intrinsic partitions. Each divided logical block is encrypted and then divided into one or more portions to produce corresponding pieces of data, and each piece of data is placed into a data packet as a payload thereof. Each data packet is transmitted to a recipient thereof, and the recipient can retrieve the pieces of data from the payloads of the packets, reconstruct the encrypted logical blocks, and manipulate the sub-stream on a per-logical block basis without necessarily decrypting each encrypted logical block.

Claims

1. A method of transmitting a stream of content having multiple sub-streams, each sub-stream comprising a part of the content and being divisible into logical blocks bounded by intrinsic partitions, the method comprising, for each sub-stream:

defining for the sub-stream a specification of the logical blocks bounded by the intrinsic partitions, wherein the intrinsic partitions are rational boundaries intrinsic to the underlying sub-stream;

dividing the sub-stream into the logical blocks bounded by the intrinsic partitions;

encrypting each divided logical block;

dividing each encrypted logical block into one or more portions to produce corresponding pieces of data;

placing each piece of data into a data packet as a payload thereof; and

transmitting each data packet to a recipient thereof, whereby the recipient retrieves the pieces of data from the payloads of the packets, reconstructs the encrypted logical blocks, and manipulates the sub-stream on a per-logical block basis prior to decrypting each encrypted logical block.

2. The method of claim 1 for transmitting a stream of content having a video sub-stream divisible into logical blocks comprising at least one frame of video each, the method comprising, for the video sub-stream:

defining for the video sub-stream a number of frames to be included in each logical block thereof; and

dividing the video sub-stream into the logical blocks each having the defined number of frames.

3. The method of claim 1 for transmitting a stream of content having an audio sub-stream divisible into logical blocks comprising at least one audio sample each, the method comprising, for the audio sub-stream:

defining for the audio sub-stream a number of samples to be included in each logical block thereof; and

dividing the audio sub-stream into the logical blocks each having the defined number of samples.

4. The method of claim 1 for transmitting a stream of content having a text sub-stream divisible into logical blocks comprising at least one byte each, the method comprising, for the text sub-stream:

defining for the text sub-stream a number of bytes to be included in each logical block thereof; and

dividing the text sub-stream into the logical blocks each having the defined number of bytes.

5. The method of claim 1 comprising defining for the sub-stream a specification of the logical blocks bounded by the intrinsic partitions based at least in part on a consideration of a size of the divided logical blocks that would be amenable for encrypting.

6. The method of claim 1 comprising defining for the sub-stream a specification of the logical blocks bounded by the intrinsic partitions based at least in part on a consideration of a size of the divided logical blocks that would be amenable to the recipient.

7. The method of claim 1 comprising dividing each encrypted logical block into a number of portions to produce corresponding pieces of data having about a particular data size.

8. A system, the system comprising:

a processor; and

a memory communicatively coupled to the processor, the memory having computer-executable instructions that when executed by the processor, provide a method for transmitting a stream of content having multiple sub-streams, each sub-stream comprising a part of the content and being divisible into logical blocks bounded by intrinsic partitions, the method comprising, for each sub-stream;

defining for the sub-stream a specification of the logical blocks bounded by the intrinsic partitions, wherein the intrinsic partitions are rational boundaries intrinsic to the underlying sub-stream;

dividing the sub-stream into the logical blocks bounded by the intrinsic partitions;

encrypting each divided logical block;

dividing each encrypted logical block into one or more portions to produce corresponding pieces of data;

placing each piece of data into a data packet as a payload thereof; and

transmitting each data packet to a recipient thereof, whereby the recipient retrieves the pieces of data from the payloads of the packets, reconstructs the encrypted logical blocks, and manipulates the sub-stream on a per-logical block basis prior to decrypting each encrypted logical block.

9. The system of claim 8 for transmitting a stream of content having a video sub-stream divisible into logical blocks comprising at least one frame of video each, the method comprising, for the video sub-stream:

defining for the video sub-stream a number of frames to be included in each logical block thereof; and

dividing the video sub-stream into the logical blocks each having the defined number of frames.

10. The system of claim 8 for transmitting a stream of content having an audio sub-stream divisible into logical blocks comprising at least one audio sample each, the method comprising, for the audio sub-stream:

defining for the audio sub-stream a number of samples to be included in each logical block thereof; and

dividing the audio sub-stream into the logical blocks each having the defined number of samples.

11. The system of claim 8 for transmitting a stream of content having a text sub-stream divisible into logical blocks comprising at least one byte each, the method comprising, for the text sub-stream:

defining for the text sub-stream a number of bytes to be included in each logical block thereof; and

dividing the text sub-stream into the logical blocks each having the defined number of bytes.

12. The system of claim 8 comprising defining for the sub-stream a specification of the logical blocks bounded by the intrinsic partitions based at least in part on a consideration of a size of the divided logical blocks that would be amenable for encrypting.

13. The system of claim 8 comprising defining for the sub-stream a specification of the logical blocks bounded by the intrinsic partitions based at least in part on a consideration of a size of the divided logical blocks that would be amenable to the recipient.

14. The system of claim 8 comprising dividing each encrypted logical block into a number of portions to produce corresponding pieces of data having a particular data size.

15. One or more computer storage media not consisting of a propagated data signal and having computer-executable instructions that when executed provide a method for transmitting a stream of content having multiple sub-streams, each sub-stream comprising a part of the content and being divisible into logical blocks bounded by intrinsic partitions, the method comprising, for each sub-stream:

defining for the sub-stream a specification of the logical blocks bounded by the intrinsic partitions, wherein the intrinsic partitions are rational boundaries intrinsic to the underlying sub-stream;

dividing the sub-stream into the logical blocks bounded by the intrinsic partitions;

encrypting each divided logical block;

dividing each encrypted logical block into one or more portions to produce corresponding pieces of data;

placing each piece of data into a data packet as a payload thereof; and

transmitting each data packet to a recipient thereof, whereby the recipient retrieves the pieces of data from the payloads of the packets, reconstructs the encrypted logical blocks, and manipulates the sub-stream on a per-logical block basis prior to decrypting each encrypted logical block.

16. The one or more computer storage media of claim 15 for transmitting a stream of content having a video sub-stream divisible into logical blocks comprising at least one frame of video each, the method comprising, for the video sub-stream:

defining for the video sub-stream a number of frames to be included in each logical block thereof; and

dividing the video sub-stream into the logical blocks each having the defined number of frames.

17. The one or more computer storage media of claim 15 for transmitting a stream of content having an audio sub-stream divisible into logical blocks comprising at least one audio sample each, the method comprising, for the audio sub-stream:

defining for the audio sub-stream a number of samples to be included in each logical block thereof; and

dividing the audio sub-stream into the logical blocks each having the defined number of samples.

18. The one or more computer storage media of claim 15 for transmitting a stream of content having a text sub-stream divisible into logical blocks comprising at least one byte each, the method comprising, for the text sub-stream:

defining for the text sub-stream a number of bytes to be included in each logical block thereof; and

dividing the text sub-stream into the logical blocks each having the defined number of bytes.

19. The one or more computer storage media of claim 15 comprising defining for the sub-stream a specification of the logical blocks bounded by the intrinsic partitions based at least in part on a consideration of a size of the divided logical blocks that would be amenable for encrypting.

20. The one or more computer storage media of claim 15 comprising defining for the sub-stream a specification of the logical blocks bounded by the intrinsic partitions based at least in part on a consideration of a size of the divided logical blocks that would be amenable to the recipient.