Method and apparatus for using counter-mode encryption to protect image data in frame buffer of a video compression system

• US 8,094,814 B2
• Filed: 05/24/2005
• Issued: 01/10/2012
• Est. Priority Date: 04/05/2005
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Chen, Xuemin (Sherman)
• Primary Examiner(s): CERVETTI, DAVID GARCIA
• Application Number:
  US11/135,906
• Publication Number:
  US 20060221760A1
• Time in Patent Office: 2,422 Days
• Field of Search: 380/217, 380/28, 380/29
• US Class Current: 380/29
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• 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

Certain aspects for protecting image data in a video compression system may include encrypting image data utilizing counter-mode scrambling. The encrypted image data may be buffered in at least one frame buffer. The buffered encrypted image data may be decrypted by utilizing counter-mode descrambling.

Claims

1. A method for protecting image data in a video compression system, the method comprising:

performing by one or more processors and/or circuits, functions comprising;

encrypting image data utilizing counter-mode scrambling, said encrypting based on calculation of a row size of an encryption cipher; and

buffering said encrypted image data in at least one frame buffer.

2. The method according to claim 1, said functions comprising initializing a counter-mode scrambler counter to perform said counter-mode scrambling.

3. The method according to claim 2, wherein counter values for said counter mode scrambler counter utilized for said encrypting are pixel addressable.

4. The method according to claim 1, said functions comprising loading an encryption key to perform said counter-mode scrambling.

5. The method according to claim 1, said functions comprising generating a ciphertext of said encrypted image data based on said calculated row size of said encryption cipher.

6. The method according to claim 5, said functions comprising generating a pad E_K(ctr)∥

E_K(ctr+1)∥

E_K(ctr+2)∥

. . . ∥

E_K(ctr+m), where m is an integer, of said encryption cipher utilizing said calculated row size, where E_K(X) denotes encipherment of an n-bit block X using an encryption key K and a block cipher E and ctr is a counter-mode scrambler counter.

7. The method according to claim 1, said functions comprising storing said encrypted image data along with its corresponding horizontal pixel address in an internal random access memory (RAM).

8. The method according to claim 1, said functions comprising arranging said buffered said encrypted image data in raster scan order.

9. The method according to claim 1, said functions comprising generating said encrypted image data by exclusive-oring (XORing) at least one plaintext string M of said image data and first |M| bits of a generated pad E_K(ctr)∥

E_K(ctr+1)∥

E_K(ctr+2)∥

. . . ∥

E_K(ctr+m), where m is an integer.

10. The method according to claim 9, said functions comprising pre-processing said generated pad E_K(ctr)∥

E_K(ctr+1)∥

E_K(ctr+2)∥

. . . ∥

E_K(ctr+m), where m is said integer, using spare processing cycles.

11. The method according to claim 1, said functions comprising protecting said buffered said encrypted image data utilizing said counter-mode scrambling, wherein said buffered said encrypted image data is compressed.

12. A method for protecting image data in a video compression system, the method comprising:

performing by one or more processors and/or circuits, functions comprising;

buffering encrypted image data in at least one frame buffer; and

decrypting said buffered encrypted image data utilizing counter-mode descrambling, said decrypting based on calculation of a row size of a decryption cipher.

13. The method according to claim 12, said functions comprising initializing a counter-mode descrambler counter to perform said counter-mode descrambling.

14. The method according to claim 13, wherein counter values for said counter mode descrambler counter utilized for said decrypting are pixel addressable.

15. The method according to claim 12, said functions comprising loading a decryption key to perform said counter-mode descrambling.

16. The method according to claim 12, said functions comprising decrypting a ciphertext of said encrypted image data based on said calculated row size of said decryption cipher.

17. The method according to claim 16, said functions comprising generating a pad E_K(ctr)∥

E_K(ctr+1)∥

E_K(ctr+2)∥

. . . ∥

E_K(ctr+m), where m is an integer, of said decryption cipher utilizing said calculated row size, where E_K(X) denotes decipherment of an n-bit block X using a decryption key K and a block cipher E and ctr is a counter-mode descrambler counter.

18. The method according to claim 12, said functions comprising storing said buffered encrypted image data along with its corresponding horizontal pixel address in an internal random access memory (RAM).

19. The method according to claim 12, said functions comprising arranging said buffered encrypted image data in raster scan order.

20. The method according to claim 12, said functions comprising generating said decrypted said buffered encrypted image data by exclusive-oring (XORing) at least one ciphertext C of said buffered encrypted image data and first |C| bits of a generated pad E_K(ctr)∥

E_K(ctr+1)∥

E_K(ctr+2)∥

. . . ∥

E_K(ctr+m), where m is an integer.

21. The method according to claim 20, said functions comprising pre-processing said generated pad E_K(ctr)∥

E_K(ctr+1)∥

E_K(ctr+2)∥

. . . ∥

E_K(ctr+m), where m is said integer, using spare processing cycles.

22. The method according to claim 12, said functions comprising protecting said buffered said encrypted image data utilizing said counter-mode descrambling, wherein said buffered said encrypted image data is compressed.