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US 7,145,492 B2Granted
Data management method
AssigneeFujitsu Limited
InventorsHideyuki Hirano, Seigo Kotani, Shinji Hashimoto
Life of this patent
Estimating the term…
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.
Claims29
A data management method comprising:
- extracting a portion of a digital content file to be distributed to prepare a preview sample as an index to the digital content file for representing the digital content file;
- preparing a substantive file by encrypting the digital content file with a content key;
- preparing user specific authorization information by encrypting the content key based upon user information;
- preparing a user specific authorization information embedded preview sample by embedding the user specific authorization information, containing information for accessing the encrypted digital content file, as invisible information in the extracted preview sample;
- synthesizing the substantive file and the user-specific-authorization-information-embedded preview sample to prepare a synthesized digital content file;
- and
- distributing the synthesized digital content file.
4 more elements
A computer readable recording medium embodying data usable by a computer system, comprising:
- a protected provider data file synthesized with an extracted accessible sample as an index to the provider data file for representing the provider data file, the sample having watermarked data-authorization information of the provider and data-authorization information of a recipient protecting the data-authorization information of the provider, to enable a recipient computer system to provide a preview function of the protected provider data file via the synthesized extracted accessible sample and to access the protected provider data file according to the synthesized extracted accessible sample having the watermarked data-authorization information of the provider and the recipient.
An apparatus, comprising:
- a programmed computer processor encrypting a content file with a content key, preparing user specific content authorization information by encrypting the content key based upon user information, embedding user specific content authorization information as a watermark in an extracted accessible sample as an index to the content file for representing the content file and synthesizing the extracted accessible sample having the watermarked user-specific-content-authorization information with the encrypted content file.
A recording medium storing instructions to control a computer according to a process comprising:
- encrypting a content file with a content key;
- preparing user specific content authorization information by encrypting the content key based upon user information;
- embedding the user specific content authorization information as a watermark in an extracted accessible sample as an index to the content file for representing the content file;
- and
- synthesizing the extracted accessible sample having the watermarked user-specific-content-authorization information with the encrypted content file.
2 more elements
A recording medium useable by an apparatus to access digital data stored thereon, comprising:
- a protected provider data file;
- and
- an extracted accessible sample synthesized with the protected provider data file and usable by the apparatus, as an index to the provider data file for representing the provider data file, the sample having watermarked data-authorization information of the provider and data-authorization information of a recipient,
- wherein the sample enables the apparatus to provide a sample function of the protected provider data file via the synthesized extracted accessible sample and enables the apparatus to access the protected provider data file according to the synthesized extracted accessible sample having the watermarked data-authorization information of the provider and the recipient.
1 more element
An apparatus, comprising:
- a content administrator to distribute a digital content file to a user according to a process comprising:
- extracting a portion of the digital content file to be distributed to prepare a preview sample as an index to the digital content file for representing the digital content file,
- preparing a substantive file by encrypting the digital content file with a content key,
- preparing user specific authorization information by encrypting the content key based upon information of the user,
- preparing a user specific authorization information embedded preview sample by embedding the user specific authorization information, containing information for accessing the encrypted digital content file, as invisible information in the extracted preview sample,
- synthesizing the substantive file and the user-specific-authorization-information-embedded preview sample to prepare a synthesized digital content file, and
- distributing the synthesized digital content file;
- and
- a client apparatus to enable use of the distributed synthesized digital content file according to a process comprising;
- receiving the distributed synthesized digital content file,
- displaying for user selection the user-specific-authorization-information-embedded preview sample,
- enabling user access to the synthesized digital content file by separating the user-specific authorization information from the preview sample, in response to a user selection of the user-specific-authorization-information-embedded preview sample,
- restoring from the user-specific authorization information a decryption key as the content key, according to the user specific authorization information, and
- decrypting the substantive file using the decryption key to enable access to the substantive file.
11 more elements
An apparatus, comprising:
- a content administrator to encrypt a digital content file with a content key;
- a center to manage the digital content file and the content key;
- and
- a user client apparatus to perform a process comprising:
- communicatively connecting to the center via a network, and
- transmitting to the center identification information of a user to request the digital content file from the center,
- wherein the center performs according to the user request a process comprising:
- extracting a portion of the user requested digital content file to prepare a preview sample as an index to the digital content file for representing the digital content file,
- preparing user specific authorization information by encrypting the content key based upon identification information of the user,
- preparing a user specific authorization information embedded preview sample by embedding the user specific authorization information, containing information for accessing the encrypted digital content file, as invisible information in the extracted preview sample,
- synthesizing the substantive file and the user-specific-authorization-information-embedded preview sample to prepare a synthesized digital content file, and
- transmitting the synthesized digital content file to the user client apparatus.
9 more elements
Dependencies are inferred from the claim text.