Method and apparatus for descrambling digital video data and digital audio data using control data

• US RE44,068 E1
• Filed: 07/17/2007
• Issued: 03/12/2013
• Est. Priority Date: 12/08/1994
• Status: Expired due to Term

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Park, Tae Joon
• Primary Examiner(s): Hewitt, II, Calvin L
• Assistant Examiner(s): Nilforoush, Mohammad A
• Application Number:
  US11/826,680
• Time in Patent Office: 2,065 Days
• Field of Search: 380/203, 380/239, 380/22, 705/51, 705/57
• US Class Current: 380/203
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00333 the key being stored in header data, e.g. in sector headers
• CPC Class Codes: G11B 20/00557 wherein further management data is encrypted, e.g. sector headers, TOC or the lead-in or lead-out areas
• CPC Class Codes: G11B 20/00753 wherein the usage restriction limits the number of copies that can be made, e.g. CGMS, SCMS, or CCI flags
• CPC Class Codes: G11B 20/00768 wherein copy control information is used, e.g. for indicating whether a content may be copied freely, no more, once, or never, by setting CGMS, SCMS, or CCI flags
• CPC Class Codes: H04N 2005/91328 the copy protection signal being a copy management signal, e.g. a copy generation management signal [CGMS]
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection

Abstract

A copy prevention method and apparatus of a digital magnetic recording/reproducing system performs the copy prevention function by encoding to insert a marker involving copy prevention function information and executing the function and allows a program supplier to realize a desired copy prevention function of various patterns, in which the marker formed by a control word for scrambling audio and video bit straps and copy prevention information for preventing an illegal copy is encrypted by an encoded key to be multiplexed with the audio and video bit strips scrambled by the control word. The marker transmitted is detected from the bit strips to be decrypted and analyzed by the encoded key to determine whether the copy is permitted or not, so that the detected marker is updated to be recorded on a video tape and the control word is produced from the marker to perform the descrambling to supply the result to a monitor to be displayed. Thus, the program supplier selects the copy prevention function, and a separate format converting apparatus is not required since a field defined within a GA format is utilized while an existing DVCR is not need to be changed for performing the copy prevention function as the data amount to be recorded is not increased.A method and apparatus for descrambling digital data are discussed. According to an embodiment, the method includes reproducing, by a digital data processing apparatus, a digital data stream from a portable recording medium, the reproduced digital data stream including a first sub data unit and at least one second sub data unit succeeding the first sub data unit, the first sub data unit including a control data portion and a scrambled data portion, the control data portion including control data, each of the second sub data unit including a scrambled data portion, each of the scrambled data portions of the first and second sub data units including scrambled digital video or audio data; initializing a descrambler of the apparatus based on the control data; and descrambling by the descrambler the scrambled data portions of the first and second sub data units based on the same control data.

Claims

1. A copy prevention method of a digital magnetic recording/reproducing system comprising:

an audio and video signal transmitting process of encrypting a marker formed by a control word for scrambling audio and video bit strips and copy prevention information for preventing an illegal copy by means of an encoding key, and multiplexing said marker with said audio and video bit strips scrambled by said control word, and

an audio and video signal receiving/recording process of detecting said marker from said transmitted bit strips, decrypting and analyzing the detected marker by means of an encoded key to determine whether copy is permitted or not, updating said detected marker to be recorded on a video tape, and generating said control word from said marker to perform a descrambling and supply the audio and video signals to be displayed on a monitor.

2. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 1, wherein said marker is placed on a transport-private-data field within said bit strips.

3. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 2, wherein said marker is comprised of a copy prevention information area recorded with said copy prevention information for preventing said illegal copy, and a control word area recorded with said control word for descrambling.

4. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 3, wherein said marker is formed of 8 bytes.

5. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 4, wherein said copy prevention area is formed of one byte.

6. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 4, wherein said control word area is formed of four bytes.

7. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 3, wherein said copy prevention information is formatted by including a generational copy control field for restricting the number of permitting said copy of a program.

8. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 7, wherein said generational copy control field comprises:

an allowable generational field for restricting the copy number of said program; and

a current generational field representing a current generation of a duplicated program.

9. A copy prevention-method of a digital magnetic recording/reproducing system as claimed in claim 1, wherein said audio and video transmitting process comprises:

an audio and video bit-strip encoding step of encoding said audio and video bit strips;

a control word generating step of generating said control word for scrambling;

a scrambling step for scrambling said encoded audio and video bit strips by means of said generated control word;

a copy prevention information generating step of generating said copy prevention information for preventing said illegal copy;

a marker generating and encrypting step of generating said marker by means of said generated control word and copy prevention information and encrypting said marker by means of said encoded key; and

a multiplexing and transmitting step of multiplexing to transmit said scrambled audio and video bit strips and encrypted marker.

10. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 1, wherein said audio and video signal receiving/recording process comprises:

a marker detecting step of demultiplexing said transmitted bit strips to detect said marker, and decrypting said marker by means of said encoded key;

a marker analyzing step of analyzing said detected marker to determine whether said copy is permitted or not, and detecting said control word;

an audio and video decoding step of descrambling and decoding said transmitted audio and video bit strips by means of said detected control word, and outputting said audio and video signals; and

a marker inserting step of updating said detected marker and encrypting said updated marker by means of said encoded key to insert the result when it is determined that said copy is permitted after analyzing said marker.

11. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 10, wherein said marker analyzing step comprises:

a copy prevention information detecting step of detecting said copy prevention information for preventing said illegal copy from said detected marker;

a copy number restricting step of comparing an allowable generation of said allowable generational field and a current generation of said current generational field representing said current generation for restricting the number of permitting said copy of said program within said detected copy prevention information, and determining whether said copy is permitted or not-to process the result; and

a control word detecting step of detecting said control word for descrambling from said detected marker.

12. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 11, wherein said copy number restricting step comprises:

comparing said allowable generation of said allowable generational field with said current generation of said current generational field to determine whether said allowable generation is below said current generation;

inhibiting said copy when it is determined that said allowable generation is below said current generation; and

permitting said copy when it is determined that said allowable generation is-not below said current generation, and proceeding to said marker inserting step.

13. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 12, wherein said step of inhibiting said copy is performed by destructing said control word or impeding an output of said control word to block a reproduction after recording.

14. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 10, wherein said control word is periodically changed.

15. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 14, wherein said control word is changed in the interval of 0.6 second.

16. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 14, wherein said marker is placed on said transport-private-data field within said bit strips whenever said control word is changed.

17. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 16, wherein said marker inserting step comprises the steps of:

updating said marker when the analysis of said marker determines to permit said copy;

encrypting said updated marker by means of said encoded key; and

replacably inserting said encrypted marker with a succeeding marker.

18. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 1, wherein said encoded key is transported via a separate transmission line to be stored.

19. A copy prevention method of a digital magnetic recording/reproducing system as claimed in claim 18, wherein said encoded key is transported via said separate transmission line for a prescribed time interval.

20. A copy prevention apparatus of a digital magnetic recording/reproducing system comprising:

an encrypted marker detecting and inserting part for detecting a marker from input bit strips, and inserting an updated marker to said bit strips to output the result;

a marker analyzing and processing part for decrypting and analyzing the encrypted marker from said marker detecting and inserting part by means of an encoded key, outputting a control word for descrambling said bit strips, and updating and encrypting the decrypted marker by means of said encoded key to output the result;

a buffer part for buffering said control word and updated and encrypted marker from said marker analyzing and processing part, and inserting said updated and encrypted marker in said marker detecting and inserting part; and

a descrambler for descrambling said bit strips provided via said marker detecting and inserting pant by means of said control word from said buffer part.

21. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 20, wherein said encoded key is transported via a separate transmission line to be stored.

22. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 21, wherein said encoded key is transported via said separate transmission line for a prescribed time interval.

23. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 20, wherein said marker is placed on a transport-private-data field within said bit strips whenever said control word is changed.

24. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 23, wherein said marker is comprised of a copy prevention information area recorded with said copy prevention information for preventing said illegal copy, and a control word area recorded with said control word for descrambling.

25. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 24, wherein said marker is formed of 8 bytes.

26. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 25, wherein said copy prevention area is formed of one byte.

27. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 25, wherein said control word area is formed of four bytes.

28. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 24, wherein said copy prevention information is formatted by including a generational copy control field for restricting the copy number of a program.

29. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 28, wherein said generational copy control field comprises:

an allowable generational field for restricting the number of permitting the copy of a program; and

a current generational field representing a current generation of a duplicated program.

30. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 20, wherein said control word is periodically changed.

31. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 30, wherein said control word is changed in the interval of 0.6 second.

32. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 30, wherein said marker is placed on a transport-private-data field within said bit strips whenever said control word is changed.

33. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 30, wherein said marker detecting and inserting part replacably inserts said updated marker with a succeeding marker.

34. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 20, wherein said marker detecting and inserting part comprises:

a marker detecting section for detecting to output said encrypted marker from said input bit strips to said marker analyzing and processing part, outputting a marker detection flag signal for informing of the position of said encrypted marker within said bit strips to said descrambler to be used as a reference signal of initializing said descrambler, and outputting said bit strips; and

a marker inserting section for inserting said updated and encrypted marker from said buffer part to said bit strips from said marker detecting section in accordance with said marker detection flag signal from said marker detecting section to output the result to said descrambler.

35. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 24, wherein said marker analyzing and processing part comprises:

a marker decoding section for decrypting said encrypted marker from said marker detecting and inserting part by means of said encoded key;

a marker analyzing section for analyzing said copy prevention information within said marker from said marker decoding section, and outputting said control word to said buffer part and a control signal for updating said marker when said copy is permitted; and

a marker updating and encoding section for updating said marker from said marker decoding section in accordance with said control signal from said marker analyzing section, and encrypting said updated marker by means of said encoded key to output the result to said buffer part.

36. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 35, wherein said marker analyzing and processing part further comprises an encoded key storage section for storing said encoded key to output it to said marker analyzing section and marker updating and encoding section.

37. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 35, wherein said marker analyzing section compares an allowable generation of an allowable generational field with a current generation of a current generational field representing a current generation of a duplicated program to determine whether said copy is permitted or not.

38. A copy prevention apparatus of a digital magnetic recording/reproducing system as claimed in claim 20, wherein said buffer part comprises:

a marker buffer for temporally storing said updated and encrypted marker from said marker analyzing and processing part, and outputting the result to said marker detecting and inserting part; and

a control word buffer for temporally storing said control word from said marker analyzing and processing part, and outputting the result to said descrambler.

39. A method of descrambling digital data using a digital data processing apparatus including a descrambler, the method comprising:

reading, by the digital data processing apparatus, a digital data stream including a plurality of 188 byte sub data units;

detecting, by the digital data processing apparatus, control data from a control portion of a first 188 byte sub data unit among the plurality of 188 byte sub data units;

directly initializing the descrambler by the digital data processing apparatus based on the detected control data;

reading, by the digital data processing apparatus, scrambled digital audio and/or digital video data from scrambled data portions of the plurality of 188 bytes sub data units;

descrambling, by the descrambler, both the scrambled digital video data and the scrambled digital audio data based on the same control data;

determining, by the digital data processing apparatus, that a minimum of a multiple of four 188 byte data blocks have been descrambled;

or

determining, by the digital data processing apparatus, that a timing point that includes a decimal fraction of 0.66 control words per second (CW/s) has passed since a previous initialization of the descrambler; and

re-initializing, by the digital data processing apparatus, the descrambler based on a new control word and based on the determination that either the minimum of the multiple of four 188 byte data blocks have been scrambled or the timing point that includes the decimal fraction of 0.66 control words per second (CW/s) has passed since the previous initialization of the descrambler.

40. The method of claim 39, wherein the detecting step detects the control data based on a signal associated with a position of the control data within the first 188 byte sub data unit.

41. The method of claim 39, further comprising:

decoding the descrambled data of the plurality of 188 byte sub data units to output an original signal.

46. The method of claim 39, wherein the control data is represented in 4 bytes.

48. The method of claim 39, further comprising:

determining, by the digital data processing apparatus, whether the reproduced digital data stream requires a copy prevention function based on identification information included in the control data portion, the identification information indicating whether or not at least a portion of the digital data stream has a data structure for copy prevention; and

detecting copy prevention information for controlling the copy prevention function from the digital data stream according to a result of the determining step.

49. The method of claim 48, wherein the copy prevention information detected in the detecting step includes one of current generation information and allowable generation information, the current generation information indicating the number of times the digital data stream has been copied, and the allowable generation information indicating the number of times permitted to copy the digital data stream.

42. An apparatus for descrambling digital data, comprising:

a processor; and

a memory connected to the processor and including executable instructions that when executed by the processor, cause the processor to perform;

reading a digital data stream including a plurality of 188 byte sub data units;

detecting control data from a control portion of a first 188 byte sub data unit among the plurality of 188 byte sub data units;

directly initializing the descrambler by the digital data processing apparatus based on the detected control data;

reading scrambled digital audio and/or digital video data from scrambled data portions of the plurality of 188 byte sub data units;

descrambling both the scrambled digital video data and the scrambled digital audio data based on the same control data;

determining, by the digital data processing apparatus, that a minimum of a multiple of four 188 byte data blocks have been descrambled;

or

determining, by the digital data processing apparatus, that a timing point that includes a decimal fraction of 0.66 control words per second (CW/s) has passed since a previous initialization of the descrambler; and

re-initializing, by the digital data processing apparatus, the descrambler based on a new control word and based on the determination that either the minimum of the multiple of four 188 byte data blocks have been scrambled or the timing point that includes the decimal fraction of 0.66 control words per second (CW/s) has passed since the previous initialization of the descrambler.

43. The apparatus of claim 42, wherein the executable instructions further cause the processor to perform:

detecting the control data based on a signal associated with a position of the control data within the first 188 byte sub data unit.

44. The apparatus of claim 42, wherein executable instructions further cause the processor to perform:

decoding the descrambled data of the plurality of 188 byte sub data units to output an original signal.

45. The apparatus of claim 42, wherein the executable instructions further cause the processor to perform:

temporarily store the detected control data in the memory.

47. The apparatus of claim 42, wherein the control data is represented in 4 bytes.

50. The apparatus of claim 42, wherein the executable instructions further cause the processor to perform:

determining whether the reproduced digital data stream requires a copy prevention function based on identification information included in the control data portion, the identification information indicating whether or not at least a portion of the digital data stream has a data structure for copy prevention; and

detecting copy prevention information for controlling the copy prevention function from the digital data stream according to a result of the determination.

51. The apparatus of claim 50, wherein the executable instructions further cause the processor to perform:

performing the copy prevention function on the reproduced digital data stream based on the detected copy prevention information.