Method and device for protecting digital data by double re-encryption

• US 7,093,295 B1
• Filed: 10/15/1999
• Issued: 08/15/2006
• Est. Priority Date: 10/15/1998
• Status: Expired due to Term

• Current Assignee: Kioba Processing, LLC (IP Investments Group LLC)
• Original Assignee: Intarsia Software LLC (Intellectual Ventures LLC)
• Inventors: Saito, Makoto
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): Baum, Ronald
• Application Number:
  US09/806,510
• Time in Patent Office: 2,496 Days
• Field of Search: 380200-203, 380/239, 713/200
• US Class Current: 726/26
• 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 20/00478 wherein contents are decrypted and re-encrypted with a different key when being copied from/to a record carrier
• CPC Class Codes: G11B 20/00536 wherein encrypted content data is subjected to a further, iterated encryption, e.g. interwoven encryption
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 21/4334 Recording operations recording of a television signal H04N5/76; arrangements for recording or accumulating broadcast information or broadcast-related information H04H60/27
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/4408 involving video stream encryption, e.g. re-encrypting a decrypted video stream for redistribution in a home network
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection

Abstract

A method and an apparatus ensuring protection of digital data are provided. In addition to re-encrypting the data using an unchangeable key, the data is double re-encrypted using a changeable key. The changeable key is used first and the unchangeable key is then used, or in another case, the unchangeable key is used first, and the changeable key is then used. In the aspect of embodiments, there is a case adopting a software, a case adopting a hardware, or a case adopting the software and the hardware in combination. The hardware using the unchangeable key developed for digital video is available. In adopting the software, encryption/decryption is performed in a region below the kernel which cannot be handled by the user to ensure the security for the program and for the key used. More concretely, encryption/decryption is performed with RTOS using a HAL and a device driver, i.e., a filter driver, a disk driver and a network driver, in an I/O manager. Either one of two filter drivers, with a file system driver between them, may be used. Further, both filter drivers may be used.

Claims

1. A method for protecting decrypted digital data from illegitimate use, said method comprising:

encrypting said decrypted digital data using a changeable key to produce changeable key re-encrypted digital data;

encrypting said changeable key re-encrypted digital data using an unchangeable key to produce changeable-unchangeable keys double re-encrypted digital data to be stored, copied and/or transferred, wherein said unchangeable key is capable of being operationally unchangeable at least during said encrypting of said changeable key re-encrypted digital data;

decrypting said copied, stored and/or transferred changeable-unchangeable keys double re-encrypted digital data using said unchangeable key to said changeable key re-encrypted digital data; and

decrypting said changeable key re-encrypted digital data using said changeable key to said decrypted digital data.

2. The method of claim 1 wherein said unchangeable key is located in a device.

5. The method according to claim 1 or 3, wherein said encrypting and decrypting using said changeable key are carried out by software executed by a computer.

6. The method according to claim 1 or 3, wherein said encrypting and decrypting using said changeable key are carried out by hardware.

7. The method according to claim 2 or 4, wherein said changeable key is supplied externally from said device.

8. The method according to claim 2 or 4, wherein said changeable key is generated in said device.

9. The method according to claim 2 or 4, wherein said encrypting and decrypting using said unchangeable key are carried out by software executed by a computer.

10. The method according to claim 1 or 3, wherein said encrypting and decrypting using said unchangeable key are carried out by hardware.

11. The method according to claim 2 or 4, wherein said unchangeable key is already placed in said device.

12. The method according to claim 2 or 4, wherein said unchangeable key is generated in said device.

13. The method according to claim 2 or 4, wherein said unchangeable key is supplied externally from said device.

14. The method according to claim 2 or 4, wherein said unchangeable key is specific to said device.

15. The method according to claim 2 or 4 wherein said unchangeable key is not specific to said device.

3. A method for protecting decrypted digital data from illegitimate use, comprising:

encrypting said decrypted digital data using an unchangeable key to produce unchangeable key re-encrypted digital data, wherein said unchangeable key is capable of being operationally unchangeable at least during said encrypting of said decrypted digital data;

encrypting said unchangeable key re-encrypted digital data using a changeable key to produce unchangeable-changeable key double re-encrypted digital data to be stored, copied and/or transferred;

decrypting said copied, stored and/or transferred unchangeable-changeable keys double re-encrypted digital data using said changeable key to said unchangeable key re-encrypted digital data; and

decrypting said unchangeable key re-encrypted digital data using said unchangeable key to said decrypted digital data.

4. The method of claim 3 wherein said unchangeable key is located in a device.

16. An apparatus for protecting decrypted digital data from illegitimate use, said apparatus comprising:

a changeable key encryption unit capable of encrypting said decrypted digital data using a changeable key to produce changeable key re-encrypted digital data;

an unchangeable key encryption unit capable of encrypting said changeable key re-encrypted digital data using an unchangeable key to produce changeable-unchangeable keys double re-encrypted digital data to be stored, copied and/or transferred, wherein said unchangeable key is capable of being operationally unchangeable at least during production of said changeable-unchangeable keys double re-encrypted digital data;

an unchangeable key decryption unit capable of decrypting said copied, stored and/or transferred changeable-unchangeable keys double re-encrypted digital data using said unchangeable key to said changeable key re-encrypted digital data; and

a changeable key decryption unit capable of decrypting said changeable key re-encrypted digital data using said changeable key to said decrypted digital data.

17. The apparatus of claim 16 wherein said unchangeable key is located in a device.

20. The apparatus according to claim 16 or 18, in which encrypting and decrypting using said changeable key are carried out by software executed by a computer.

21. The apparatus according to claim 16 or 18, in which encrypting and decrypting using said changeable key are carried out by hardware.

22. The apparatus according to claim 17 or 19, wherein said changeable key is supplied externally from said device.

23. The apparatus according to claim 17 or 19, wherein said changeable key is generated in said device.

24. The apparatus according to claim 16 or 18, in which encrypting and decrypting using said unchangeable key are carried out by software executed by a computer.

25. The apparatus according to claim 16 or 18, in which encrypting and decrypting using said unchangeable key are carried out by hardware.

26. The apparatus according to claim 17 or 19, wherein said unchangeable key is already placed in said device.

27. The apparatus according to claim 17 or 19, wherein said unchangeable key is generated in said device.

28. The apparatus according to claim 17 or 19, wherein said unchangeable key is supplied externally from said device.

29. The apparatus according to claim 17 or 19, wherein said unchangeable key is specific to said device.

30. The apparatus according to claim 17 or 19, wherein said unchangeable key is not specific to said device.

18. An apparatus for protecting decrypted digital data from illegitimate use, said apparatus comprising:

an unchangeable key encryption unit capable of encrypting said decrypted digital data using an unchangeable key to produce unchangeable key re-encrypted digital data, wherein said unchangeable key is capable of being operationally unchangeable at least during production of said unchangeable key re-encrypted digital data;

a changeable key encryption unit capable of encrypting said unchangeable key re-encrypted digital data using a changeable key to produce changeable-unchangeable keys double re-encrypted digital data to be stored, copied and/or transferred;

a changeable key decryption unit capable of decrypting said copied, stored and/or transferred

changeable-unchangeable keys double re-encrypted digital data using said changeable key to said unchangeable key re-encrypted digital data; and

an unchangeable key decryption unit capable of decrypting said unchangeable key re-encrypted digital data using said unchangeable key to said decrypted digital data.

19. The apparatus of claim 18 wherein said unchangeable key is located in a device.

31. A method for protecting decrypted digital data from illegitimate use, said decrypted digital data being decrypted from digital data encrypted using a first changeable key, said method comprising:

encrypting said decrypted digital data using a second changeable key to produce second changeable key re-encrypted digital data;

encrypting said second changeable key re-encrypted digital data using an unchangeable key to produce unchangeable second changeable keys double re-encrypted digital data to be stored, wherein said unchangeable key is capable of being operationally unchangeable at least during said encrypting of said second changeable key re-encrypted digital data;

decrypting said stored unchangeable-second changeable keys double re-encrypted digital data using said unchangeable key to said second changeable key re-encrypted digital data;

encrypting said second changeable key re-encrypted digital data using a third changeable key to produce third changeable-second changeable keys double re-encrypted digital data to be copied and/or transferred;

decrypting said copied and/or transferred third changeable-second changeable keys double re-encrypted digital data using said third changeable key to said second changeable key re-encrypted digital data; and

decrypting said second changeable key re-encrypted digital data using said second changeable key to said decrypted digital data.

32. The method of claim 31 wherein said unchangeable key is located in a device.

35. The method according to claim 31 or 33 wherein said encrypting and decrypting using said second changeable key are carried out by software executed by a computer.

36. The method according to claim 31 or 33 wherein said encrypting and decrypting using said second changeable key are carried out by hardware.

37. The method according to claim 32 or 34 wherein said second changeable key is supplied externally from said device.

38. The method according to claim 32 or 34 wherein said second changeable key is generated in said device.

39. The method according to claim 31 or 33 wherein said encrypting and decrypting using said third changeable key are carried out by software executed by a computer.

40. The method according to claim 31 or 34 wherein said encrypting and decrypting using said third changeable key are carried out by hardware.

41. The method according to claim 32 or 34 wherein said third changeable key is supplied externally from said device.

42. The method according to claim 32 or 34 wherein said third changeable key is generated in said device.

43. The method according to claim 31 or 33 wherein said encrypting and decrypting using said unchangeable key are carried out by software executed by a computer.

44. The method according to claim 31 or 33 wherein said encrypting and decrypting using said unchangeable key are carried out by hardware.

45. The method according to claim 32 or 34 wherein said unchangeable key is already placed in said device.

46. The method according to claim 32 or 34 wherein said unchangeable key is generated in said device.

47. The method according to claim 32 or 34 wherein said unchangeable key is supplied externally from said device.

48. The method according to claim 32 or 34 wherein said unchangeable key is specific to said device.

49. The method according to claim 32 or 34 wherein said unchangeable key is not specific to said device.

33. A method for protecting decrypted digital data from illegitimate use, said decrypted digital data being decrypted from digital data encrypted using a first changeable key, said method comprising:

encrypting said decrypted digital data using an unchangeable key to produce unchangeable key re-encrypted digital data, wherein said unchangeable key is capable of being operationally unchangeable at least during said encrypting of said decrypted digital data, and encrypting said unchangeable key re-encrypted digital data using a second changeable key to produce second changeable-unchangeable keys double re-encrypted digital data to be stored;

decrypting said stored second changeable-unchangeable keys double re-encrypted digital data using said second changeable key to said unchangeable key re-encrypted digital data;

decrypting said unchangeable key re-encrypted digital data using said unchangeable key to said decrypted digital data;

encrypting said decrypted digital data using a third changeable key to produce third changeable key re-encrypted digital data, and encrypting said third changeable key re-encrypted digital data using said second changeable key to produce second changeable-third changeable keys double re-encrypted digital data to be copied and/or transferred;

decrypting said copied and/or transferred second changeable-third changeable keys double re-encrypted digital data using said second changeable key to said third changeable key re-encrypted digital data; and

decrypting said third changeable key re-encrypted digital data using said third changeable key to said decrypted digital data.

34. The method of claim 33 wherein said unchangeable key is located in a device.

50. An apparatus for protecting decrypted digital data from illegitimate use, said decrypted digital data being decrypted from digital data encrypted using a first changeable key, said apparatus comprising:

a second changeable key encryption unit capable of encrypting said decrypted digital data using a second changeable key to produce second changeable key re-encrypted digital data;

an unchangeable key encryption unit capable of encrypting said second changeable key re-encrypted digital data using an unchangeable key to produce unchangeable-second changeable keys double re-encrypted digital data to be stored, wherein said unchangeable key is capable of being operationally unchangeable at least during production of said unchangeable-second changeable keys double re-encrypted digital data;

an unchangeable key decryption unit capable of decrypting said stored unchangeable-second changeable keys double re-encrypted digital data using said unchangeable key to said second changeable key re-encrypted digital data;

a third changeable key encryption unit capable of encrypting said second changeable key re-encrypted digital data using a third changeable key to produce third changeable-second changeable keys double re-encrypted digital data to be copied and/or transferred;

a third changeable key decryption unit capable of decrypting said copied and/or transferred changeable-second changeable keys double re-encrypted digital data using said third changeable key to said second changeable key re-encrypted digital data; and

a second changeable key decryption unit capable of decrypting said second changeable key re-encrypted digital data using said second changeable key to decrypted digital data.

51. The apparatus of claim 50 wherein said unchangeable key is located may be in a device.

54. The apparatus according to claim 50 or 52 wherein said encrypting and decrypting using said second changeable key are carried out by software executed by a computer.

55. The apparatus according to claim 50 or 52 wherein said encrypting and decrypting using said second changeable key are carried out by hardware.

56. The apparatus according to claim 51 or 53 wherein said second changeable key is supplied externally from said device.

57. The apparatus according to claim 51 or 53 wherein said second changeable key is generated in said device.

58. The apparatus according to claim 51 or 53 wherein said encrypting and decrypting using said third changeable key are carried out by software executed by a computer.

59. The apparatus according to claim 50 or 52 wherein said encrypting and decrypting using said third changeable key are carried out by hardware.

60. The apparatus according to claim 51 or 53 wherein said third changeable key is supplied externally from said device.

61. The apparatus according to claim 51 or 53 wherein said third changeable key is generated in said device.

62. The apparatus according to claim 50 or 52 wherein said encrypting and decrypting using said unchangeable key are carried out by software executed by a computer.

63. The apparatus according to claim 50 or 52 wherein said encrypting and decrypting using said unchangeable key are carried out by hardware.

64. The apparatus according to claim 51 or 53 wherein said unchangeable key is already placed in said device.

65. The apparatus according to claim 51 or 53 wherein said unchangeable key is generated in said device.

66. The apparatus according to claim 51 or 53 wherein said unchangeable key is supplied externally from said device.

67. The apparatus according to claim 51 or 53 wherein said unchangeable key is specific to said device.

68. The apparatus according to claim 51 or 53 wherein said unchangeable key is not specific to said device.

52. An apparatus for protecting decrypted digital data from illegitimate use, said decrypted digital data being decrypted from digital data encrypted using a first changeable key, said apparatus comprising:

an unchangeable key encryption unit capable of encrypting said decrypted digital data using an unchangeable key to produce unchangeable key re-encrypted digital data, wherein said unchangeable key is capable of being operationally unchangeable at least during production of said unchangeable key re-encrypted digital data, and a second changeable key encryption unit capable of encrypting said unchangeable key re-encrypted digital data using a second changeable key to produce second changeable-unchangeable key double re-encrypted digital data to be stored;

a second changeable key decryption unit capable of decrypting said stored second changeable-unchangeable keys double re-encrypted digital data using said second changeable key to unchangeable key re-encrypted digital data, and an unchangeable key decryption unit capable of decrypting said unchangeable key re-encrypted digital data using said unchangeable key to decrypted digital data;

a third changeable key encryption unit capable of encrypting said decrypted digital data using a third changeable key to produce third changeable key re-encrypted digital data, and a second changeable key encryption unit capable of encrypting said third changeable key re-encrypted digital data using said second changeable key to produce second changeable-third changeable keys double re-encrypted digital data to be copied and/or transferred; and

a second changeable key decryption unit capable of decrypting said copied and/or transferred second changeable-third changeable keys double re-encrypted digital data using said second changeable key to said third changeable key re-encrypted digital data, and a third changeable key decryption unit capable of decrypting said third changeable key re-encrypted digital data using said third changeable key to decrypted digital data.

53. The apparatus of claim 52 wherein said unchangeable key is located in a device.

69. A method for protecting digital data from illegitimate use, said method comprising:

determining whether said digital data is subject to be protected or not;

encrypting said digital data, determined to be protected, using an unchangeable key to produce unchangeable key encrypted digital data, wherein said unchangeable key is capable of being operationally unchangeable at least during said encrypting of said digital data;

storing, copying and/or transferring said unchangeable key encrypted digital data;

decrypting said stored, copied and/or transferred unchangeable key encrypted digital data using said unchangeable key to decrypted digital data; and

utilizing said stored, copied and/or transferred unchangeable key encrypted digital data and said decrypted digital data.

70. The method of claim 69 wherein said unchangeable key is located in a device.

71. The method according to claim 69, wherein said encrypting and decrypting using said unchangeable key are carried out by software executed by a computer.

72. The method according to claim 69, wherein said encrypting and decrypting using said unchangeable key are carried out by hardware.

73. The method according to claim 69, in which encrypting and decrypting using said unchangeable key are controlled by identifying information which is added to said digital data.

74. The method according to claim 73, in which encrypting and decrypting are carried out if said identifying information is present.

75. The method according to claim 73, in which encrypting and decrypting are carried out if said identifying information is absent.

76. The method according to claim 70, wherein said unchangeable key is already placed in said device.

77. The method according to claim 70, wherein said unchangeable key is generated in said device.

78. The method according to claim 70, wherein said unchangeable key is supplied externally from said device.

79. The method according to claim 76, 77 or 78, wherein said unchangeable key is specific to said device.

80. The method according to claim 76, 77 or 78, wherein said unchangeable key is not specific to said device.

81. An apparatus for protecting digital data from illegitimate use, said apparatus comprising:

determining means for determining whether said digital data is subject to be protected or not;

means for encrypting said digital data, determined being subject to be protected, using an unchangeable key to produce unchangeable key encrypted digital data, wherein said unchangeable key is capable of being operationally unchangeable at least during said encrypting of said digital data;

means for storing, copying and/or transferring said unchangeable key encrypted digital data;

means for decrypting said stored, copied and/or transferred unchangeable key encrypted digital data to said decrypted digital data; and

means for utilizing said stored, copied and/or transferred unchangeable key encrypted digital data and said decrypted digital data.

82. The apparatus of claim 81 wherein said unchangeable key is located in a device.

83. The apparatus according to claim 81, wherein encrypting and decrypting using said unchangeable key are carried out by software executed by a computer.

84. The apparatus according to claim 81, wherein encrypting and decrypting using said unchangeable key are carried out by hardware.

85. The apparatus according to claim 81, wherein encrypting and decrypting using said unchangeable key are controlled by identifying information which is added to said digital data.

86. The apparatus according to claim 81, wherein encrypting and decrypting are carried out if said identifying information is present.

87. The apparatus according to claim 81, wherein encrypting and decrypting are carried out if said identifying information is absent.

88. The apparatus according to claim 82, wherein said unchangeable key is already placed in said device.

89. The apparatus according to claim 82, wherein said unchangeable key is generated in said device.

90. The apparatus according to claim 82, wherein said unchangeable key is supplied externally from said device.

91. The apparatus according to claim 88, 89 or 90 wherein said unchangeable key is specific to said device.

92. The apparatus according to claim 88, 89 or 90 wherein said unchangeable key is not specific to said device.