Data management method

• US 20030177093A1
• Filed: 04/27/2000
• Published: 09/18/2003
• Est. Priority Date: 05/27/1999
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Hashimoto, Shinji, Kotani, Seigo, Hirano, Hideyuki
• Granted Patent: US 7,145,492 B2
• Time in Patent Office: Days
• US Class Current: 705/50
• CPC Class Codes: G06F 21/107 License processing; Key processing
• CPC Class Codes: H04N 21/23473 by pre-encrypting
• CPC Class Codes: H04N 21/23892 involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/25866 Management of end-user data customer care in data networks H04L41/5077
• CPC Class Codes: H04N 21/4627 Rights management associated to the content security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/8355 involving usage data, e.g. number of copies or viewings allowed
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• CPC Class Codes: H04N 2201/3205 of identification information, e.g. name or ID code H04N2201/3209 takes precedence
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/3238 using a coded or compressed version of the image data itself
• CPC Class Codes: H04N 2201/3246 of data relating to permitted access or usage, e.g. level of access or usage parameters for digital rights management [DRM] related to still images
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/3281 Encryption; Ciphering

Abstract

A data management method that by encrypting and distributing digital content prevents copyright infringement, and that prevents authorization information for decrypting the encrypted digital content from being damaged or otherwise lost. Encrypted content 45 is prepared by encrypting digital content 11 with a content key 44. A portion of the digital content 11 is extracted as sample data 41. A secret key 46, by which the content key 44 is encrypted with user information 14, is embedded as invisible information into the sample data 41, thus preparing watermarked sample data 47. The watermarked sample data 47 is synthesized with the encrypted content 45 to form synthesized data 48. The synthesized data 48 is distributed.

Claims

1. A data management method comprising:

preparing a substantive data unit by encrypting digital content that is for distribution;

extracting a portion of the digital content as sample data, and preparing a sample data unit wherein authorization information containing information for a content key employed as an encryption key when encrypting the digital content is embedded as invisible information; and

preparing synthesized data wherein the substantive data unit and the sample data unit are synthesized, and distributing the synthesized data.

2. The data management method set forth in claim 1, wherein use is enabled by separating the authorization information from the sample data unit, restoring the content key for decrypting the substantive data unit from said authorization information, and employing the content key to decrypt the substantive data unit into the original digital content.

3. The data management method set forth in claim 1, the sample data being image data wherein at least one process among image processing, resizing, compressing and a γ

-compensation is executed on image data contained in the digital content.

4. The data management method set forth in claim 1, wherein the sample data is index data for representing the substantive data unit.

5. The data management method set forth in claim 4, wherein the synthesized data contains a plurality of substantive data units based on a plurality of digital content items, and contains a plurality of sample data units corresponding to the plurality of substantive data units;

and wherein sample data constituting the plurality of sample data units is linked with respective corresponding ones of the plurality of substantive data units.

6. The data management method set forth in claim 1, wherein the sample data units are data structuralized in one of JPEG and MPEG formats, and

the synthesized data is prepared by add-on synthesizing the substantive data unit to the sample data unit using the format of the sample data unit.

7. The data management method set forth in claim 1, the authorization information being information wherein the content key is encrypted, with the encryption key being at least one of user identification information, equipment identification information loaded in user-employed computers, CPU identification information loaded in user-employed computers, and identification information unique to digital-content-storing recording media.

8. The data management method set forth in claim 1, the authorization information being information wherein the content key is encrypted, with the encryption key being identification information common to a plurality of users.

9. The data management method set forth in claim 1, the authorization information being information wherein the content key is encrypted, with the encryption key being at least one of identification information unique to distributors of the digital content, and identification information unique to authors of the digital content.

10. The data management method set forth in claim 7, wherein a decryption key for decrypting the encrypted content key is in common with the encryption key for encrypting, being a shared key based on exclusive information transmitted and received among users and content distributors, using symmetric cryptography.

11. The data management method set forth in claim 8, wherein a decryption key for decrypting the encrypted content key is in common with the encryption key for encrypting, being a shared key based on exclusive information transmitted and received among users and content distributors, using symmetric cryptography.

12. The data management method set forth in claim 9, wherein a decryption key for decrypting the encrypted content key is in common with the encryption key for encrypting, being a shared key based on exclusive information transmitted and received among users and content distributors, using symmetric cryptography.

13. The data management method set forth in claim 7, wherein the digital content distributors encrypt the content key employing a secret key, and the users decrypt the encrypted content key employing a public key provided in advance from the digital content distributors, using public-key cryptography.

14. The data management method set forth in claim 8, wherein the digital content distributors encrypt the content key employing a secret key, and the users decrypt the encrypted content key employing a public key provided in advance from the digital content distributors, using public-key cryptography.

15. The data management method set forth in claim 9, wherein the digital content distributors encrypt the content key employing a secret key, and the users decrypt the encrypted content key employing a public key provided in advance from the digital content distributors, using public-key cryptography.

16. The data management method set forth in claim 1, wherein the sample data unit comprises as invisible information a use count of times a user has used the digital content;

characterized in that the invisible information is rewritten each time a user uses the digital content.

17. The data management method set forth in claim 1, wherein the sample data unit comprises as invisible information authorization information to enable use count control;

characterized in that the invisible information is rewritten when a user uses the digital content a predetermined number of times and more.

18. The data management method set forth in claim 16, characterized in that the invisible information is rewritten on decrypting and reading the substantive data unit.

19. The data management method set forth in claim 16, characterized in that the invisible information is rewritten when use of the digital content is ended.

20. The data management method set forth in claim 17, characterized in that the invisible information is rewritten on decrypting and reading the substantive data unit.

21. The data management method set forth in claim 17, characterized in that the invisible information is rewritten when use of the digital content is ended.

22. The data management method set forth in claim 16, wherein the invisible information in the sample data unit comprises an error recovery function by containing redundant information.

23. The data management method set forth in claim 16, characterized in that limits on read-out and use in decrypting the substantive data unit are governed based on the invisible information in the sample data unit.

24. The data management method set forth in claim 16, characterized in that one of year, month, date, and time limits within which read-out and use is possible in decrypting the substantive data unit are governed based on the invisible information in the sample data unit.