The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 23, 2010
Filed:
Feb. 15, 2007
Yasuo Hatano, Yokohama, JP;
Kunihiko Miyazaki, Yokohama, JP;
Kenji Matsumoto, Yokohama, JP;
Yoji Shimizu, Tokyo, JP;
Yasuo Hatano, Yokohama, JP;
Kunihiko Miyazaki, Yokohama, JP;
Kenji Matsumoto, Yokohama, JP;
Yoji Shimizu, Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Disclosure of information is controlled selectively depending on users such that a plurality of users having different roles bearing no inclusive relation with one another can access the same area. Content is divided into a plurality of areas. For each of the areas obtained by division, secret keys (encryption/decryption keys in symmetric-key cryptography) are generated. The generated keys are encrypted using public keys in public-key cryptography, which are set in advance for the users depending on their respective roles. In the case where the content is to be disclosed to a plurality of users having different roles, the encryption of secret keys is performed separately for each user. These encrypted contents and encrypted secret keys are used to generate encrypted text.