Title:
KEY SHARING SYSTEM, METHOD, PROGRAM, SERVER DEVICE, AND TERMINAL DEVICE
Document Type and Number:
WIPO Patent Application WO/2023/127963
Kind Code:
A1
Abstract:
[Problem] To more safely share encrypted data. [Solution] After verification by a verification unit 106 with regard to a set of key disclosure permission information 134 and an identification token 131 transmitted from a first client terminal 102, a key registration unit 107 registers a record 122 that includes a key 133 and the key disclosure permission information 134 to a database 121 of a key sharing server 101 and transmits key identification information 135 for identifying the record to the first client terminal 102. The first client terminal 102 transmits, to a second client terminal 103, data 139 that includes: encrypted data 138 obtained by encrypting transmission data using a cryptographic key 136 for the encryption of data after first processing, which is outputted from a first cryptographic key processing unit 109; a cryptographic key 137 for the decryption of data after first processing, which is outputted from the first cryptographic key processing unit 109; and key identification information 135 obtained from the key registration unit 107. The second client terminal 103 makes an inquiry to a key disclosure unit 110 using the key identification information 135 acquired from the received data 139 and an identification token 132 of the second client terminal 103. The key disclosure unit 110 acquires a set of a key 133 that corresponds to the key identification information 135 and the key disclosure permission information 134 from the database 121 and reports the key 133 to the second client terminal if the identification token 132 is included in a key disclosure permission range indicated by the key disclosure permission information 134. The second client terminal 103 generates, using the reported key 133, a cryptographic key 140 for the decryption of data after second processing from the cryptographic key 137 for the decryption of data after first processing that was acquired from the data 139 and executes decryption on the encrypted data 138 within the data 139 using the cryptographic key 140.
Inventors:
KAMBAYASHI TORU (JP)
Application Number:
PCT/JP2022/048657
Publication Date:
July 06, 2023
Filing Date:
December 28, 2022
Export Citation:
Assignee:
KAMBAYASHI TORU (JP)
International Classes:
H04L9/08; G06F21/62; H04L9/14; H04L9/32; H04L67/06
Foreign References:
| JP2014514889A | 2014-06-19 | |||
| US20190372758A1 | 2019-12-05 |
Other References:
TATSU KAMIBAYASHI, TAKU KATO, TATSUYUKI MATSUSHITA, KENTARO UMEZAWA, SHINJI YAMANAKA: "1B2-2: JetJigsaw: New Proposal of Digital Rights Management System Using Peer to Peer Network", 2009 CRYPTOGRAPHY AND INFORMATION SECURITY SYMPOSIUM; SCIS 2009 [CD-ROM]; JANUARY 20-23, 2009, IEICE, JP, 1 January 2009 (2009-01-01) - 23 January 2009 (2009-01-23), JP, pages 1 - 6, XP009547836
Attorney, Agent or Firm:
INOUE & CO. (JP)
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