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.

Date of Patent:
Jun. 04, 2019

Filed:

Sep. 07, 2016
Applicants:

Kabushiki Kaisha Toshiba, Minato-ku, JP;

Toshiba Solutions Corporation, Kawasaki-shi, JP;

Inventors:

Masanobu Koike, Tama, JP;

Yoshihiro Fujii, Tokyo, JP;

Assignees:

KABUSHIKI KAISHA TOSHIBA, Minato-ku, JP;

TOSHIBA SOLUTIONS CORPORATION, Kawasaki-shi, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04L 9/08 (2006.01); H04L 9/30 (2006.01);
U.S. Cl.
CPC ...
H04L 9/0891 (2013.01); H04L 9/0897 (2013.01); H04L 9/30 (2013.01); H04L 9/3073 (2013.01); H04L 2209/76 (2013.01);
Abstract

A data management device according to an embodiment stores first encrypted data obtained by encrypting plain text data with a first public key of a first user device. The data management device stores a first re-encryption key for re-encrypting the first encrypted data without decrypting to obtain first re-encrypted data decryptable with a private key of a second user device. The data management device stores a conversion key generated from a first private key corresponding to the first public key and a second private key of the first user device. The data management device converts the first encrypted data into second encrypted data with the conversion key. The data management device The data management device converts the first re-encryption key into a second re-encryption key with the conversion key.


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