Copy-guard system and information recording medium used in the same system

• US 6,556,679 B1
• Filed: 11/19/1998
• Issued: 04/29/2003
• Est. Priority Date: 11/20/1997
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Endoh, Kenjiro, Yamada, Hisashi, Kato, Takehisa, Katoh, Taku, Endoh, Naoki
• Primary Examiner(s): Barron, Gilberto
• Assistant Examiner(s): Callahan, Paul E.
• Application Number:
  US09/195,914
• Time in Patent Office: 1,622 Days
• Field of Search: 713/176, 713/200, 380/201, 380/202, 380/203, 705/57, 705/58, 705/51
• US Class Current: 380/203
• 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 20/00166 involving measures which result in a restriction to authorised contents recorded on or reproduced from a record carrier, e.g. music or software
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/18 Error detection or correction; Testing , e.g. of drop-outs
• 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
• CPC Class Codes: H04N 5/945 for signals recorded by pulse code modulation

Abstract

In an embodiment, a copy-guard system is provided that includes a decoding section for decoding digital data, which is encoded and error-correction-coded, from an information recording medium in which key information encoded for the digital data is recorded, an encoded digital data acquisition section for acquiring digital data encoded by error-correcting the digital data decoded by the decoding section, a detection section for detecting an error position and an error symbol value of the encoded digital data, identification information detection section for detecting an identification information representing whether the information recording medium is original or copied and which is replaced with a part of the digital data encoded and error-correction-coded, based on the error position and the error symbol value detected by the detection section, a determination section for determining whether a copy of the information recording medium is protected, and a copy protection section.

Claims

1. A copy-guard system comprising:

first decoding means for decoding digital data, which is encoded and error-correction-coded, from an information recording medium in which key information encoded for the digital data is recorded;

encoded digital data acquisition means for acquiring digital data encoded by error-correcting the digital data decoded by the first decoding means;

detection means for detecting an error position and an error symbol value of the encoded digital data acquired by the encoded digital data acquisition means;

identification information detection means for detecting an identification information that is replaced with a part of the digital data encoded and error-correction-coded based on the error position and the error symbol value detected by the detection means, wherein the identification information represents whether the information recording medium is original or copied;

first determination means for determining whether a copy of the information recording medium is protected based on the identification information detected by the identification information detection means; and

copy protection means for protecting a copy of the information recording medium based on determination results of the first determination means.

2. The copy-guard system according to claim 1, further comprising:

second decoding means for decoding the key information from the information recording medium;

third decoding means for decoding the encoded digital data acquired by the encoded digital data acquisition means, based on the key information decoded by the second decoding means; and

reproduction means for reproducing the digital data decoded by the third decoding means.

3. The copy-guard system according to claim 1, wherein the digital data is obtained by converting analog contents.

4. The copy-guard system according to claim 1, wherein the first determination means encodes a control signal indicative of the determination results and outputs the encoded control signal, and the copy protection means decodes the encoded control signal and protects a copy of the information recording medium in response to the decoded control signal.

5. The copy-guard system according to claim 1, wherein the identification information is replaced with a predetermined symbol of the error-correction-coded digital data.

6. The copy-guard system according to claim 1, wherein the first determination means comprises:

count means for counting a number of the identification information detected by the identification information detection means;

second determination means for determining whether the number of the identification information counted by the count means exceeds a predetermined value; and

third determination means for determining whether a copy of the information recording medium is protected based on determination results of the second determination means.

7. The copy-guard system according to claim 1, wherein the first determination means determines whether copy of the information recording medium is protected based on positional information of the identification information detected by the identification information detection means.

8. The copy-guard system according to claim 1, wherein the first determination means comprises:

first conversion means for converting the control signal indicative of the determination results into a first control signal by performing a predetermined operation using a random number;

first encoding means for encoding the first control signal obtained by the first conversion means; and

second encoding means for encoding the random number, and

the copy protection means comprises;

second decoding means for decoding the first control signal encoded by the first encoding means;

third decoding means for decoding the random number encoded by the second encoding means;

second conversion means for converting the first control signal decoded by the second decoding means into the control signal by performing a predetermined operation using the random number decoded by the third decoding means; and

means for protecting a copy in response to the control signal generated by the second conversion means.

9. The copy-guard system according to claim 1, wherein the identification information is an error correction code, and the identification information detection means corrects the identification information using an error correction ability of the error correction code.

10. A copy-guard system comprising:

first decoding means for decoding digital data, which is encoded and error-correction-coded by a product code, from an information recording medium in which key information encoded for the digital data is recorded;

first acquisition means for acquiring digital data encoded and error-correction-coded by an inner code when the digital data decoded by the first decoding means is error-corrected by an outer code;

detection means for detecting an error position and an error symbol value of the digital data acquired by the first acquisition means;

identification information detection means for detecting an identification information that is replaced with a part of the digital data encoded and error-correction-coded by the inner code based on the error position and the error symbol value detected by the detection means, wherein the identification information represents whether the information recording medium is original or copied;

first determination means for determining whether a copy of the information recording medium is protected based on the identification information detected by the identification information detection means; and

copy protection means for protecting a copy of the information recording medium based on determination results of the first determination means.

11. The copy-guard system according to claim 10, further comprising:

second acquisition means for acquiring digital data encoded by error-correcting using the inner code the digital data, which is acquired by the first acquisition means;

second decoding means for decoding the key information from the information recording medium;

third decoding means for decoding the encoded digital data acquired by the second acquisition means, based on the key information decoded by the second decoding means; and

reproduction means for reproducing the digital data decoded by the third decoding means.

12. The copy-guard system according to claim 10, wherein the digital data is obtained by converting analog contents.

13. The copy-guard system according to claim 10, wherein the first determination means encodes a control signal indicative of the determination results and outputs the encoded control signal, and the copy protection means decodes the encoded control signal and protects a copy of the information recording medium in response to the decoded control signal.

14. The copy-guard system according to claim 10, wherein the first determination means comprises:

count means for counting a number of the identification information detected by the identification information detection means;

second determination means for determining whether the number of the identification information counted by the count means exceeds a predetermined value; and

third determination means for determining whether a copy of the information recording medium is protected based on determination results of the second determination means.

15. The copy-guard system according to claim 10, wherein the first determination means determines whether copy of the information recording medium is protected based on positional information of the identification information detected by the identification information detection means.

16. The copy-guard system according to claim 10, wherein the first determination means comprises:

first conversion means for converting the control signal indicative of the determination results into a first control signal by performing a predetermined operation using a random number;

first encoding means for encoding the first control signal obtained by the first conversion means; and

second encoding means for encoding the random number, and

the copy protection means comprises;

second decoding means for decoding the first control signal encoded by the first encoding means;

third decoding means for decoding the random number encoded by the second encoding means;

second conversion means for converting the first control signal decoded by the second decoding means into the control signal by performing a predetermined operation using the random number decoded by the third decoding means; and

means for protecting a copy in response to the control signal generated by the second conversion means.

17. The copy-guard system according to claim 10, wherein the identification information is an error correction code, and the identification information detection means corrects the identification information using an error correction ability of the error correction code.

18. The copy-guard system according to claim 10, wherein the first determination means determines whether a copy of the information recording medium is protected based on the error position and the error symbol value detected by the detection means and a pattern of the identification information stored in advance.

19. A copy-guard system comprising:

first decoding means for decoding digital data, which is encoded and error-correction-coded by a product code, from an information recording medium in which key information encoded for the digital data is recorded;

first acquisition means for acquiring digital data encoded and error-correction-coded by an inner code when the digital data decoded by the first decoding means is error-corrected by an outer code;

first detection means for detecting a first error position and a first error symbol value of the digital data acquired by the first acquisition means;

second acquisition means for acquiring digital data encoded by error-correcting the digital data, which is acquired by the first acquisition means, by the inner code;

second detection means for detecting a second error position and a second error symbol value of the encoded digital data acquired by the second acquisition means;

identification information detection means for detecting an identification information that is replaced with a part of the digital data encoded and error-correction-coded using the product code based on the first error position and the first error symbol value detected by the first detection means and the second error position and the second error symbol value detected by the second detection means, wherein the identification information represents whether the information recording medium is original or copied;

first determination means for determining whether a copy of the information recording medium is protected based on the identification information detected by the identification information detection means; and

copy protection means for protecting a copy of the information recording medium based on determination results of the first determination means.

20. The copy-guard system according to claim 19, further comprising:

second decoding means for decoding the key information from the information recording medium;

third decoding means for decoding the encoded digital data acquired by the second acquisition means, based on the key information decoded by the second decoding means; and

reproduction means for reproducing the digital data decoded by the third decoding means.

21. The copy-guard system according to claim 19, wherein the digital data is obtained by converting analog contents.

22. The copy-guard system according to claim 19, wherein the first determination means encodes a control signal indicative of the determination results and outputs the encoded control signal, and the copy protection means decodes the encoded control signal and protects a copy of the information recording medium in response to the decoded control signal.

23. The copy-guard system according to claim 19, wherein the identification information is replaced with a predetermined symbol of the error-correction-coded digital data.

24. The copy-guard system according to claim 19, wherein the first determination means comprises:

count means for counting a number of the identification information detected by the identification information detection means;

second determination means for determining whether the number of the identification information counted by the count means exceeds a predetermined value; and

third determination means for determining whether a copy of the information recording medium is protected based on determination results of the second determination means.

25. The copy-guard system according to claim 19, wherein the first determination means determines whether copy of the information recording medium is protected based on positional information of the identification information detected by the identification information detection means.

26. The copy-guard system according to claim 19, wherein the first determination means comprises:

first conversion means for converting the control signal indicative of the determination results into a first control signal by performing a predetermined operation using a random number;

first encoding means for encoding the first control signal obtained by the first conversion means; and

second encoding means for encoding the random number, and

the copy protection means comprises;

second decoding means for decoding the first control signal encoded by the first encoding means;

third decoding means for decoding the random number encoded by the second encoding means;

second conversion means for converting the first control signal decoded by the second decoding means into the control signal by performing a predetermined operation using the random number decoded by the third decoding means; and

means for protecting a copy in response to the control signal generated by the second conversion means.

27. The copy-guard system according to claim 19, wherein the identification information is an error correction code, and the identification information detection means corrects the identification information using an error correction ability of the error correction code.

28. A copy-guard system comprising:

first decoding means for decoding digital data, which is encoded and error-correction-coded by a product code, from an information recording medium in which key information encoded for the digital data is recorded;

identification information detection means for detecting an identification information that is replaced with a part of the digital data encoded and error-correction-coded using a product code based on the error position and the error symbol value detected by the detection means, wherein the identification information represents whether the information recording medium is original or copied;

first determination means for determining whether a copy of the information recording medium is protected based on the identification information detected by the identification information detection means; and

copy protection means for protecting a copy of the information recording medium based on determination results of the first determination means.

29. The copy-guard system according to claim 28, further comprising:

second decoding means for decoding the key information from the information recording medium;

acquisition means for acquiring digital data encoded by error-correcting the digital data, which is decoded by the first decoding means, by the product code;

third decoding means for decoding the encoded digital data acquired by the acquisition means, based on the key information decoded by the second decoding means; and

reproduction means for reproducing the digital data decoded by the third decoding means.

30. The copy-guard system according to claim 28, wherein the digital data is obtained by converting analog contents.

31. The copy-guard system according to claim 28, wherein the first determination means encodes a control signal indicative of the determination results and outputs the encoded control signal, and the copy protection means decodes the encoded control signal and protects a copy of the information recording medium in response to the decoded control signal.

32. The copy-guard system according to claim 28, wherein the identification information is replaced with a predetermined symbol of the error-correction-coded digital data.

33. The copy-guard system according to claim 28, wherein the first determination means comprises:

count means for counting a number of the identification information detected by the identification information detection means;

second determination means for determining whether the number of the identification information counted by the count means exceeds a predetermined value; and

third determination means for determining whether a copy of the information recording medium is protected based on determination results of the second determination means.

34. The copy-guard system according to claim 28, wherein the first determination means determines whether copy of the information recording medium is protected based on positional information of the identification information detected by the identification information detection means.

35. The copy-guard system according to claim 28, wherein the first determination means comprises:

first conversion means for converting the control signal indicative of the determination results into a first control signal by performing a predetermined operation using a random number;

first encoding means for encoding the first control signal obtained by the first conversion means; and

second encoding means for encoding the random number, and

the copy protection means comprises;

second decoding means for decoding the first control signal encoded by the first encoding means;

third decoding means for decoding the random number encoded by the second encoding means;

second conversion means for converting the first control signal decoded by the second decoding means into the control signal by performing a predetermined operation using the random number decoded by the third decoding means; and

means for protecting a copy in response to the control signal generated by the second conversion means.

36. The copy-guard system according to claim 28, wherein the identification information is an error correction code, and the identification information detection means corrects the identification information using an error correction ability of the error correction code.

37. A copy-guard system comprising:

first decoding means for decoding digital data, which is encoded and error-correction-coded, from an information recording medium in which key information encoded for the digital data is recorded;

encoded digital data acquisition means for acquiring digital data encoded by error-correcting the digital data decoded by the first decoding means;

detection means for detecting an error position and an error symbol value of the encoded digital data acquired by the encoded digital data acquisition means;

second decoding means for decoding the digital data acquired by the encoded digital data acquisition means;

extraction means for extracting positional information of an identification information, which is embedded in the digital data decoded by the second decoding means, as watermark data;

identification information detection means for detecting the identification information that is replaced with a part of the digital data encoded and error-correction-coded based on the error position and the error symbol value detected by the detection means and the positional information of identification information extracted by the extraction means, wherein the identification information represents whether the information recording medium is original or copied;

determination means for determining whether a copy of the information recording medium is protected based on the identification information detected by the identification information detection means; and

copy protection means for protecting a copy of the information recording medium based on determination results of the determination means.

38. A copy-guard system comprising:

decoding means for decoding digital data, which is encoded and error-correction-coded, from an information recording medium in which key information encoded for the digital data is recorded;

encoded digital data acquisition means for acquiring digital data encoded by error-correcting the digital data decoded by the decoding means;

detection means for detecting an error position and an error symbol value of the encoded digital data acquired by the encoded digital data acquisition means;

compression means for compressing the key information encoded and stored in the information recording medium;

extraction means for extracting an identification information based on the key information compressed by the compression means and the error position and the error symbol value detected by the detection means, wherein the identification information represents whether the information recording medium is original or copied;

determination means for determining whether a copy of the information recording medium is protected based on the identification information extracted by the extraction means; and

copy protection means for protecting a copy of the information recording medium based on determination results of the determination means.

39. A computer program product for operating a computer, the computer program product comprising:

a computer readable medium;

digital data encoded and error-correction coded, the digital data including an identification information that is replaced with part of the digital data and recorded, wherein the identification information represents whether the computer readable medium is original or copied; and

key information encoded for the digital data encoded and error-correction-coded,

wherein each of the digital data and the encoded key information is recorded on the computer readable medium in executable form and loadable into the computer for execution by a processor.

40. A method for protecting information, comprising:

decoding digital data, which is encoded and error-correction-coded, from an information recording medium in which key information encoded for the digital data is recorded;

acquiring digital data encoded by error-correcting the decoded digital data;

detecting an error position and an error symbol value of the acquired encoded digital data;

detecting an identification information that is replaced with a part of the encoded and error-correction-coded digital data encoded and error-correction-coded based on the detected error position and error symbol value, wherein the identification information represents whether the information recording medium is original or copied;

determining whether a copy of the information recording medium is protected based on the detected identification information; and

protecting a copy of the information recording medium based on the determination.