Data processing method and apparatus

• US 7,072,488 B2
• Filed: 07/05/2002
• Issued: 07/04/2006
• Est. Priority Date: 07/11/2001
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Iwamura, Keiichi
• Primary Examiner(s): Patel, Kanjibhai
• Assistant Examiner(s): MISTRY, O NEAL RAJAN
• Application Number:
  US10/188,870
• Publication Number:
  US 20030012406A1
• Time in Patent Office: 1,460 Days
• Field of Search: 382/100, 348/473, 380/203
• US Class Current: 382/100
• CPC Class Codes: H04N 1/32203 Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32208 involving changing the magnitude of selected pixels, e.g. overlay of information or super-imposition H04N1/32219, H04N1/32224 take precedence
• CPC Class Codes: H04N 1/32229 with selective or adaptive application of the additional information, e.g. in selected regions of the image H04N1/32213 takes precedence
• CPC Class Codes: H04N 1/32272 Encryption or ciphering
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes

Abstract

An encrypted image C(i, j) is generated by exclusively ORing pseudo random number values, which are generated using a key k₀ as a key, and respective bits, except for the LSBs, of B pixel data at respective pixel positions (i, j) of digital image data I(i, j). First check bits B(i, j) corresponding to the pixel positions of pixels are generated based on the image C(i, j) and a conversion table. A digitally watermarked image I′(i, j) is obtained by embedding the first check bits in the LSBs of the corresponding pixel data of the digital image data. Check bits U(i, j) are obtained by encrypting pixel data by exclusively ORing respective bits, except for the LSBs, of B pixel data at positions (i, j) of the image I′(i, j) and the pseudo random numbers. If each check bit U(i, j) matches the LSB of the corresponding B pixel data, it is determined that the corresponding pixel is free from tampering.

Claims

1. A data processing apparatus comprising:

check bit generation means for generating first check bits on the basis of pseudo random number values corresponding to data block positions of a digital contents which is formed by a plurality of data blocks, and of the data blocks; and

means for multiplexing the first check bits in the corresponding data blocks,

wherein said check bit generation means comprises means for generating encrypted blocks by exclusively ORing the pseudo random number values and the data blocks, and means for generating the first check bits on the basis of error detection codes of the encrypted blocks.

2. A data processing apparatus comprising:

demultiplexing means for demultiplexing first check bits multiplexed in a digital contents;

check bit generation means for generating second check bits on the basis of pseudo random number values corresponding to data block positions of a digital contents which is formed by a plurality of data blocks, and of the data blocks; and

comparison means for comparing the first and second check bits,

wherein said check bit generation means comprises means for generating encrypted blocks by exclusively ORing the pseudo random number values and the data blocks, and means for generating the second check bits on the basis of error detection codes of the encrypted blocks.

3. A data processing apparatus comprising:

first pattern generation means for generating first patterns having self-synchronism for a digital contents, which is formed by a plurality of data blocks in a given order;

second pattern generation means for generating second patterns depending on an image;

embedding pattern generation means for generating embedding patterns on the basis of the first and second patterns; and

pattern embedding means for embedding the embedding patterns in the data blocks,

wherein said second pattern generation means comprises pseudo random number generation means for generating pseudo random numbers on the basis of an initial value, and generates the second patterns on the basis of the pseudo random numbers and data block values of the digital contents.

4. The apparatus according to claim 3, wherein said second pattern generation means comprises pseudo random number generation means for generating pseudo random numbers on the basis of an initial value, and generates the second patterns on the basis of the pseudo random numbers, data block values of the digital contents, and pseudo random number values generated by said pseudo random number generation means in correspondence with data block positions of the digital contents.

5. The apparatus according to claim 3, wherein said first pattern generation means generates the first patterns on the basis of initial values corresponding to the respective data blocks.

6. The apparatus according to claim 3, wherein said second pattern generation means comprises a table that stores pseudo random numbers generated by said pseudo random number generation means in an order of addresses, and generates the second patterns on the basis of outputs from said table in response to the data block values input to said table.

7. A data processing apparatus comprising:

first pattern generation means for generating first patterns having self-synchronism for a digital contents, which is formed by a plurality of data blocks in a given order;

pseudo random number generation means for generating pseudo random numbers on the basis of an initial value;

encrypted block generation means for generating encrypted data blocks on the pseudo random numbers and the plurality of data blocks;

check bit generation means for generating check bits by applying an error detection code to the encrypted data blocks;

embedding pattern generation means for generating an embedding pattern on the basis of the check bits and the first patterns; and

pattern embedding means for embedding the embedding patterns in the corresponding data blocks.

8. The apparatus according to claim 7, wherein each of the plurality of data blocks is encrypted according to an order of the data block.

9. The apparatus according to claim 7, wherein the digital contents is a digital image, and the data blocks are pixels.

10. A data processing apparatus comprising:

third pattern extraction means for extracting third patterns corresponding to a plurality of data blocks which have a given order;

fourth pattern generation means for generating fourth patterns on the basis of an image to be verified;

fifth pattern generation means for generating fifth patterns on the basis of the fourth and third patterns; and

check means for checking self-synchronism of the fifth patterns.

11. The apparatus according to claim 10, wherein said fourth pattern generation means comprises pseudo random number generation means for generating pseudo random numbers on the basis of an initial value, and generates the fourth patterns on the basis of the pseudo random numbers and data block values of a digital contents to be verified.

12. The apparatus according to claim 11, wherein said fourth pattern generation means comprises a table that stores pseudo random numbers generated by said pseudo random number generation means in an order of addresses, and generates the fourth patterns on the basis of outputs from said table in response to the data block values input to said table.

13. The apparatus according to claim 10, wherein said fourth pattern generation means comprises pseudo random number generation means for generating pseudo random numbers on the basis of an initial value, and generates the fourth patterns on the basis of the pseudo random numbers, data block values of a digital contents to be verified, and pseudo random number values generated by said pseudo random number generation means in correspondence with data block positions of the digital contents to be verified.

14. The apparatus according to claim 10, wherein said self-synchronism check generation means generates self-synchronization patterns on the basis of initial values corresponding to the data blocks.

15. The apparatus according to claim 10, further comprising means for correcting enlargement/reduction and rotation of a digital contents.

16. The apparatus according to claim 10, wherein a pattern is used to detect if a digital contents is partially cut, and has an order which is alternately determined in vertical and horizontal directions, or is randomly determined, or is predetermined.

17. A data processing apparatus comprising:

pseudo random number generation means for generating pseudo random numbers on the basis of an initial value;

encrypted block generation means for generating encrypted blocks from a plurality of data blocks to be verified, which have a given order, and the pseudo random numbers;

check bit generation means for generating check bits by applying an error detection code to the encrypted data blocks;

means for calculating differences between the check bits and check bits contained in the respective data blocks; and

check means for checking self-synchronism of the differences.

18. The apparatus according to claim 17, wherein each of the plurality of data blocks to be verified is encrypted according to an order of the data block.

19. A data processing apparatus comprising:

first pattern generation means for generating first patterns having self-synchronism for a digital contents, which is formed by a plurality of data blocks in a given order;

embedding pattern generation means for generating embedding patterns from the first patterns generated by said first pattern generation means;

pattern embedding means for embedding the embedding pattern generated by said embedding pattern generation means in the respective data blocks;

third pattern extraction means for extracting third patterns from the plurality of data blocks which have the given order; and

check means for checking self-synchronism of the third patterns extracted by said third pattern extraction means.

20. The apparatus according to claim 19, wherein said check means generates self-synchronization pattern on the basis of initial values corresponding to respective data blocks, and checks the self-synchronism.

21. The apparatus according to claim 19, further comprising means for correcting enlargement/reduction and rotation of the digital contents.

22. A data processing method comprising:

a check bit generation step of generating first check bits on the basis of pseudo random number values corresponding to data block positions of a digital contents which is formed by a plurality of data blocks, and of the data blocks; and

a step of multiplexing the first check bits in the corresponding data blocks,

wherein said check bit generation step comprises a step of generating encrypted blocks by exclusively ORing the pseudo random number values and the data blocks, and a step of generating the first check bits on the basis of error detection codes of the encrypted blocks.

23. A data processing method comprising:

a demultiplexing step of demultiplexing first check bits multiplexed in a digital contents;

a check bit generation step of generating second check bits on the basis of pseudo random number values corresponding to data block positions of a digital contents which is formed by a plurality of data blocks, and of the data blocks; and

a comparison step of comparing the first and second check bits,

wherein said check bit generation step comprises a step of generating encrypted blocks by exclusively ORing the pseudo random number values and the data blocks, and a step of generating the second check bits on the basis of error detection codes of the encrypted blocks.

24. A data processing method comprising:

a first pattern generation step of generating first patterns having self-synchronism for a digital contents, which is formed by a plurality of data blocks in a given order;

a second pattern generation step of generating second patterns depending on an image;

an embedding pattern generation step of generating embedding patterns on the basis of the first and second patterns; and

a pattern embedding step of embedding the embedding patterns in the data blocks,

wherein said second pattern generation step comprises a pseudo random number generation step of generating pseudo random numbers on the basis of an initial value, and includes a step of generating the second patterns on the basis of the pseudo random numbers and data block values of the digital contents.

25. The method according to claim 24, wherein said second pattern generation step comprises a pseudo random number generation step of generating pseudo random numbers on the basis of an initial value, and includes a step of generating the second patterns on the basis of the pseudo random numbers, data block values of the digital contents, and pseudo random number values generated at said pseudo random number generation step in correspondence with data block positions of the digital contents.

26. The method according to claim 24, wherein said first pattern generation step generates the first patterns on the basis of initial values corresponding to the respective data blocks.

27. The method according to claim 24, wherein said second pattern generation step comprises a table that stores pseudo random numbers generated at said pseudo random number generation step in an order of addresses, and includes a step of generating the second patterns on the basis of outputs from said table in response to the data block values input to said table.

28. The method according to claim 24, wherein each of the plurality of data blocks is encrypted in accordance with an order of the data block.

29. A data processing method comprising:

a first pattern generation step of generating first patterns having self-synchronism for a digital contents, which is formed by a plurality of data blocks in a given order;

a pseudo random number generation step of generating pseudo random numbers on the basis of an initial value;

an encrypted block generation step of generating encrypted data blocks on the pseudo random numbers and the plurality of data blocks;

a check bit generation step of generating check bits by applying an error detection code to the encrypted data blocks;

an embedding pattern generation step of generating an embedding pattern on the basis of the check bits and the first patterns; and

a pattern embedding step of embedding the embedding patterns in the corresponding data blocks.

30. A data processing method comprising:

a third pattern extraction step of extracting third patterns corresponding to a plurality of data blocks which have a given order;

a fourth pattern generation step of generating fourth patterns on the basis of an image to be verified, and the third patterns;

a fifth pattern generation step of generating fifth patterns on the basis of the fourth patterns and the image to be verified; and

a check step of checking self-synchronism of the fifth patterns.

31. The method according to claim 30, wherein said third pattern generation step comprises a pseudo random number generation step of generating pseudo random numbers on the basis of an initial value, and

said fourth pattern generation step includes a step of generating the fourth patterns on the basis of the pseudo random numbers and data block values of a digital contents to be verified.

32. The method according to claim 30, wherein said third pattern generation step comprises a pseudo random number generation step of generating pseudo random numbers on the basis of an initial value, and

said fourth pattern generation step includes a step of generating the fourth patterns on the basis of the pseudo random numbers, data block values of a digital contents to be verified, and pseudo random number values generated at said pseudo random number generation step in correspondence with data block positions of the digital contents to be verified.

33. The method according to claim 32, wherein said fourth pattern generation step comprises a table that stores pseudo random numbers generated at said pseudo random number generation step in an order of addresses, and includes a step of generating the fourth patterns on the basis of outputs from said table in response to the data block values input to said table.

34. The method according to claim 30, wherein said third pattern generation step includes a step of generating the third patterns on the basis of initial values corresponding to the data blocks.

35. The method according to claim 30, further comprising a step of correcting enlargement/reduction and rotation of a digital contents.

36. The method according to claim 30, wherein a pattern is used to detect if a digital contents is partially cut, and has an order which is alternately determined in vertical and horizontal directions, or is randomly determined, or is predetermined.

37. The method according to claim 30, wherein the digital contents is a digital image, and the data blocks are pixels.

38. A data processing method comprising:

a pseudo random number generation step of generating pseudo random numbers on the basis of an initial value;

an encrypted block generation step of generating encrypted blocks from a plurality of data blocks to be verified, which have a given order, and the pseudo random numbers;

a check bit generation step of generating check bits by applying an error detection code to the encrypted data blocks;

a step of calculating differences between the check bits and check bits contained in the respective data blocks; and

a check step of checking self-synchronism of the differences.

39. The method according to claim 38, wherein each of the plurality of data blocks to be verified is encrypted according to an order of the data block.

40. A data processing method comprising:

a first pattern generation step of generating first patterns having self-synchronism for a digital contents, which is formed by a plurality of data blocks in a given order;

an embedding pattern generation step of generating embedding patterns from the first patterns generated at said first pattern generation step;

a pattern embedding step of embedding the embedding pattern generated at said embedding pattern generation step in the respective data blocks;

a third pattern generation step of generating third patterns corresponding to a plurality of data blocks which have a given order; and

a check step of checking self-synchronism of the third patterns.

41. The method according to claim 40, wherein said first pattern generation step includes a step of generating the first patterns on the basis of initial values corresponding to the respective data blocks.

42. The method according to claim 40, wherein said check step includes a step of generating self-synchronization patterns on the basis of initial values corresponding to respective data blocks, and checking the self-synchronism on the basis of the self-synchronization patterns.

43. The method according to claim 40, further comprising a step of correcting enlargement/reduction and rotation of the digital contents.