Fujitsu Corporation

Shinji Hashimoto

Hideyuki Hirano

Seigo Kotani

Shigetoshi Mochizuki

Kazuhiko Muramoto

Eiki Hattori

A document distributing method is proposed using access control information separated into invisible data embedded as an electronic watermark and visible data described in a structured document to achieve prevention of unauthorized alteration of document data, authentication thereof, and prevention of unauthorized access thereto. The method has a step of separating access control information into a first access control information and a second access control information, a step of embedding the first access control information into administrative information-enclosing data, a step of setting an administrative identifier for making the administrative information-enclosing data in which the first access control information has been embedded be an information item in the document data, and a step of enclosing, in the administrative identifier, information content of the administrative information-enclosing data and the second access control information for creating the access control information for accessing the document data together with the first access control information.

Document distribution method and document management method

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 contentis prepared by encrypting digital contentwith a content keyA portion of the digital contentis extracted as sample dataA secret keyby which the content keyis encrypted with user informationis embedded as invisible information into the sample datathus preparing watermarked sample dataThe watermarked sample datais synthesized with the encrypted contentto form synthesized dataThe synthesized datais distributed.

Data management method

Data administration method which prevents the infringement of a copyright by encrypting and distributing digital content, and readily grasps which contents are contained in the digital content included in the data. Preparing symbol information symbolized so as to visually and auditorily recognize the contents of the digital content that conduct distribution (Step S), embedding the symbol information in a header data section (Step S), encrypting the digital content (Step S), embedding consent information including the information on the contents key in the header data section as an electronic watermark (Step S), and compositing the real data section and the consent-information-added header data section and distributing the composite data (Step S).

Data administration method

Method of data operation facilitating utilization of legitimate users without violating the copyright and literary property of digital content. A part of digital content () is duplicated to create discrete data unit (), and is encrypted with content key (). Content key () and image-compositing information () are encrypted with secret key () to create authorization information (). Content information () is visibly embedded in digital content (). Authorization information-added data unit () in which authorization information () is embedded as invisible information and encrypted discrete data unit information () are composited into composite data (), which is then distributed.

Growing community of inventors

Kawasaki, Japan

Shinji Hashimoto