Data processing method and apparatus

• US 7,181,043 B2
• Filed: 09/12/2005
• Issued: 02/20/2007
• 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): Mehta; Bhavesh M.
• Assistant Examiner(s): Shah; Utpal
• Application Number:
  US11/222,958
• Publication Number:
  US 20060050926A1
• Time in Patent Office: 526 Days
• Field of Search: None
• 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 a plurality of keys on the basis of pseudo random number values corresponding to pixel positions of pixels, correlating the keys with pixel positions of digital image data by a predetermined method, encrypting pixel data at the pixel positions corresponding to the keys, and generating first check bits corresponding to the pixel positions of pixels of the digital image data; and

multiplexing means for multiplexing the first check bits in corresponding pixel data of the digital image data,

wherein the predetermined method that correlates the keys with pixel positions determines correspondence between a plurality of neighboring pixel data and one key.

2. A data processing apparatus comprising:

check bit generation means for generating a plurality of keys on the basis of pseudo random number values corresponding to pixel positions of pixels, correlating the keys with pixel positions of digital image data by a predetermined method, encrypting pixel data at the pixel positions corresponding to the keys, and generating first check bits corresponding to the pixel positions of pixels of the digital image data; and

multiplexing means for multiplexing the first check bits in corresponding pixel data of the digital image data,

wherein the predetermined method that correlates the keys with pixel positions determines correspondence between a plurality of randomly selected pixel data and one key.

3. A data processing apparatus comprising:

check bit generation means for generating a plurality of keys on the basis of pseudo random number values corresponding to pixel positions of pixels, correlating the keys with pixel positions of digital image data by a predetermined method, encrypting pixel data at the pixel positions corresponding to the keys, and generating first check bits corresponding to the pixel positions of pixels of the digital image data; and

multiplexing means for multiplexing the first check bits in corresponding pixel data of the digital image data,

wherein the predetermined method that correlates the keys with pixel positions determines correspondence between one randomly selected pixel data and one key.

4. A data processing method comprising:

a check bit generation step of generating a plurality of keys on the basis of pseudo random number values corresponding to pixel positions of pixels, correlating the keys with pixel positions of digital image data by a predetermined method, encrypting pixel data at the pixel positions corresponding to the keys, and generating first check bits corresponding to the pixel positions of pixels of the digital image data; and

a multiplexing step of multiplexing the first check bits in corresponding pixel data of the digital image data,

wherein the predetermined method that correlates the keys with pixel positions determines correspondence between a plurality of neighboring pixel data and one key.

5. A data processing method comprising:

a check bit generation step of generating a plurality of keys on the basis of pseudo random number values corresponding to pixel positions of pixels, correlating the keys with pixel positions of digital image data by a predetermined method, encrypting pixel data at the pixel positions corresponding to the keys, and generating first check bits corresponding to the pixel positions of pixels of the digital image data; and

a multiplexing step of multiplexing the first check bits in corresponding pixel data of the digital image data,

wherein the predetermined method that correlates the keys with pixel positions determines correspondence between a plurality of randomly selected pixel data and one key.

6. A data processing method comprising:

a check bit generation step of generating a plurality of keys on the basis of pseudo random number values corresponding to pixel positions of pixels, correlating the keys with pixel positions of digital image data by a predetermined method, encrypting pixel data at the pixel positions corresponding to the keys, and generating first check bits corresponding to the pixel positions of pixels of the digital image data; and

a multiplexing step of multiplexing the first check bits in corresponding pixel data of the digital image data,

wherein the predetermined method that correlates the keys with pixel positions determines correspondence between one randomly selected pixel data and one key.