Method and system for digital image authentication

• US 20020114452A1
• Filed: 12/21/2001
• Published: 08/22/2002
• Est. Priority Date: 12/21/2000
• Status: Abandoned Application

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Hamilton, Jon W.
• Application Number:
  US10/028,017
• Publication Number:
  US 20020114452A1
• Time in Patent Office: Days
• US Class Current: 380/42
• CPC Class Codes: H04N 1/32101 Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
• CPC Class Codes: H04N 1/32144 embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/4426 involving separate means, e.g. a server, a magnetic card
• CPC Class Codes: H04N 1/444 to a particular document or image or part thereof
• CPC Class Codes: H04N 1/4486 using digital data encryption
• CPC Class Codes: H04N 2201/3205 of identification information, e.g. name or ID code H04N2201/3209 takes precedence
• CPC Class Codes: H04N 2201/3215 of a time or duration
• CPC Class Codes: H04N 2201/3226 of identification information or the like, e.g. ID code, index, title, part of an image, reduced-size image
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/3235 Checking or certification of the authentication information, e.g. by comparison with data stored independently
• CPC Class Codes: H04N 2201/3236 Details of authentication information generation
• CPC Class Codes: H04N 2201/3266 of text or character information, e.g. text accompanying an image H04N2201/3226 takes precedence
• CPC Class Codes: H04N 2201/3276 of a customised additional information profile, e.g. a profile specific to a user ID
• CPC Class Codes: H04N 2201/3281 Encryption; Ciphering

Abstract

A digital image (27) is taken by a digital camera (12) and a serial number (22) is associated with the digital image. The digital image is encrypted by the camera using a camera key (20) to form an encrypted image (28). The encrypted image is then communicated to an authentication center (14). The authentication center associates the encrypted image with the serial number identifying the camera and an encrypted camera key (50). At a later time, a digital image is sent by a verifying entity (16) to the authorization center to determine if the digital image has been altered. The authorization center then decrypts the encrypted image, compares the digital image to the decrypted encrypted image and reports the result to the verifying entity. Also, the digital image is encrypted. The digital image is partitioned into at least one partition. A P box is applied to each partition. A first and second S box are applied to each partition. The encrypted image is generated based the P box, the first S box and the second S box. The authentication center decrypts the digital image. The encrypted digital image is decrypted by determining at least one partition based on the encrypted digital image. At least one trajectory associated with the encrypted image is reconstructed. A reverse S2 box, a reverse S1 box and a reverse P box are applied to the partitions. The original digital image is generated based on the first reverse S box, the second reverse S box and the reverse P box.

Claims

1. A method for encrypting a digital image comprising:

providing an unencrypted image;

partitioning the unencrypted image into at least one partition;

applying a P box to each partition;

applying a first S box to each partition;

applying a second S box to each partition;

generating an encrypted image based the P box, the first S box and the second S box.

2. The method according to claim 1, wherein providing the unencrypted image comprises generating the unencrypted image at a camera.

3. The method according to claim 1, wherein the unencrypted image comprises an image portion and a text potion and wherein partitioning the unencrypted image comprises:

determining a dimension of the unencrypted image;

partitioning the image portion into at least one image partition blocks based on a minimum partition block size and a maximum partition block size;

partitioning the text portion into at least one text partition blocks based on the minimum partition block size and the maximum partition block size;

indexing the image partition blocks; and

indexing the text partition blocks.

4. The method according to claim 3, wherein the minimum partition block size is less than a length of a cryptographic key and the maximum block size is less than the length of the cryptographic times the dimensionality of a product space associated with the second S box.

5. The method according to claim 1, wherein applying the P box comprises:

applying a bit enumeration to each partition;

permuting a plurality of bits in each partition; and

rotating a plurality of nibbles in each partition.

6. The method according to claim 1, wherein applying the first S box comprises:

applying a first non-linear feedback shift register to the partition;

selecting a nibble from the partition;

comparing the selected nibble against an entry in a predetermined table;

modifying the nibble based on the comparison;

applying a second nonlinear feedback shift register to the partition;

applying a rotation matrix to at least one of the nibbles in the partition; and

determining whether a predetermined number of twiddles has been applied to the partition.

7. The method according to claim 6, wherein the first non-linear feedback shift register comprises a non-linear feedback shift register number three and the second non-linear feedback shift register comprises a non-linear feedback shift register number four.

8. The method according to claim 1, wherein the second S box comprises:

determining a trajectory associated with each partition; and

determining a ring associated with each trajectory.

9. A method for digital image decrypting comprising:

providing an encrypted digital image;

reconstruct at least one partition based on the encrypted digital image;

reconstruct at least one trajectory associated with the encrypted digital image;

applying a reverse S2 box to the partitions based on the trajectories;

applying a reverse S1 box to the partitions;

applying a reverse P box to the partitions; and

generating an unencrypted digital image based on the first reverse S box, the second reverse S box and the reverse P box.

10. The method according to claim 9, wherein reconstructing at least one trajectory comprises:

determining a set of at least one possible trajectory;

applying an S2 box to each possible trajectory in the set to generate an encrypted possible trajectory;

comparing the encrypted possible trajectory to the encrypted digital image; and

determining at least one actual trajectory when the comparison finds a match.

11. The method according to claim 9, wherein applying the reverse S1 box comprises:

applying a rotation matrix to at least one of the nibbles in the partition

applying a second nonlinear feedback shift register to the partition

selecting a nibble from the partition;

comparing the selected nibble against an entry in a predetermined table;

modifying the nibble based on the comparison; and

applying a first non-linear feedback shift register to the partition.

12. The method according to claim 11, wherein the first non-linear feedback shift register comprises a non-linear feedback shift register number three and the second non-linear feedback shift register comprises a non-linear feedback shift register number four.

13. The method according to claim 9, wherein applying the reverse P box comprises:

rotating a plurality of nibbles in each partition;

permuting a plurality of bits in each partition; and

applying a bit enumeration to each partition.

14. The method according to claim 9, wherein applying the reverse S2 box comprises:

determining a ring associated with each trajectory; and

determining a trajectory associated with each partition.

16. The system according to claim 15, wherein the software is further operable to generate the unencrypted image at a camera.

17. The system according to claim 15, wherein the unencrypted image comprises an image portion and a text potion and wherein the software is further operable to:

determine a dimension of the unencrypted image;

partition the image portion into at least one image partition blocks based on a minimum partition block size and a maximum partition block size;

partition the text portion into at least one text partition blocks based on the minimum partition block size and the maximum partition block size;

index the image partition blocks; and

index the text partition blocks.

18. The system according to claim 17, wherein the minimum partition block size is less than a length of a cryptographic key and the maximum block size is less than the length of the cryptographic times the dimensionality of a product space associated with the second S box.

19. The system according to claim 15, wherein the software is further operable to:

apply a bit enumeration to each partition;

permute a plurality of bits in each partition; and

rotate a plurality of nibbles in each partition.

20. The system according to claim 15, wherein the software is further operable to:

apply a first non-linear feedback shift register to the partition;

select a nibble from the partition;

compare the selected nibble against an entry in a predetermined table;

modify the nibble based on the comparison;

apply a second nonlinear feedback shift register to the partition;

apply a rotation matrix to at least one of the nibbles in the partition; and

determine whether a predetermined number of twiddles has been applied to the partition.

21. The system according to claim 20, wherein the first non-linear feedback shift register comprises a non-linear feedback shift register number three and the second non-linear feedback shift register comprises a non-linear feedback shift register number four.

22. The system according to claim 15, wherein the software is further operable to:

determining a trajectory associated with each partition; and

determining a ring associated with each trajectory.

24. The method according to claim 23, wherein reconstructing at least one trajectory comprises:

determining a set of at least one possible trajectory;

applying an S2 box to each possible trajectory in the set to generate an encrypted possible trajectory;

comparing the encrypted possible trajectory to the encrypted digital image; and

determining at least one actual trajectory when the comparison finds a match.

25. The method according to claim 23, wherein applying the reverse S1 box comprises:

applying a rotation matrix to at least one of the nibbles in the partition

applying a second nonlinear feedback shift register to the partition

selecting a nibble from the partition;

comparing the selected nibble against an entry in a predetermined table;

modifying the nibble based on the comparison; and

applying a first non-linear feedback shift register to the partition.

26. The method according to claim 25, wherein the first non-linear feedback shift register comprises a non-linear feedback shift register number three and the second non-linear feedback shift register comprises a non-linear feedback shift register number four.

27. The method according to claim 23, wherein applying the reverse P box comprises:

rotating a plurality of nibbles in each partition;

permuting a plurality of bits in each partition; and

applying a bit enumeration to each partition.

28. The method according to claim 23, wherein applying the reverse S2 box comprises:

determining a ring associated with each trajectory; and

determining a trajectory associated with each partition.

15. A system for encrypting a digital image comprising:

software stored in memory and operable to;

provide an unencrypted image;

partition the unencrypted image into at least one partition;

apply a P box to each partition;

apply a first S box to each partition;

apply a second S box to each partition; and

generate an encrypted image based the P box, the first S box and the second S box.

23. A method for digital image decrypting comprising:

providing an encrypted digital image;

reconstruct at least one partition based on the encrypted digital image;

reconstruct at least one trajectory associated with the encrypted digital image;

applying a reverse S2 box to the partitions based on the trajectories;

applying a reverse S1 box to the partitions;

applying a reverse P box to the partitions; and

generating an unencrypted digital image based on the first reverse S box, the second reverse S box and the reverse P box.

29. A system for encrypting a digital image comprising:

means for providing an unencrypted image;

means for partitioning the unencrypted image into at least one partition;

means for applying a P box to each partition;

means for applying a first S box to each partition;

means for applying a second S box to each partition; and

means for generating an encrypted image based the P box, the first S box and the second S box.

30. A system for digital image decrypting comprising:

means for providing an encrypted digital image;

means for reconstruct at least one partition based on the encrypted digital image;

means for reconstruct at least one trajectory associated with the encrypted digital image;

means for applying a reverse S2 box to the partitions based on the trajectories;

means for applying a reverse S1 box to the partitions;

means for applying a reverse P box to the partitions; and

means for generating an unencrypted digital image based on the first reverse S box, the second reverse S box and the reverse P box.