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:
Oct. 30, 2018
Filed:
Feb. 20, 2015
Mitsubishi Electric Corporation, Tokyo, JP;
MITSUBISHI ELECTRIC CORPORATION, Tokyo, JP;
Abstract
A data storage unit () stores encrypted data while remaining in an encrypted state, and stores decryption conditions to define a user attribute of a decryption-permission user who is permitted to decrypt the encrypted data. In a case wherein revocation information to indicate a user attribute of a revoked user who is no longer the decryption-permission user has been added to the decryption condition when update timing arrives, a revocation information removing unit () removes the revocation information from the decryption condition while the encrypted data remains in the encrypted state. Further, the revocation information removing unit () transmits the encrypted data and the decryption conditions from which the revocation information has been removed to a re-encryption apparatus that performs re-encryption in a proxy re-encryption scheme, and receives, from the re-encryption apparatus, the encrypted data that has be re-encrypted in the proxy re-encryption scheme using the decryption condition from which the revocation information has been removed. A refresh processing unit () updates the encrypted data that has been re-encrypted and the decryption condition from which the revocation information has been removed.