Title:
ENCRYPTION DEVICE, DECRYPTION DEVICE, DECRYPTABILITY VERIFICATION DEVICE, CIPHER SYSTEM, ENCRYPTION METHOD, AND ENCRYPTION PROGRAM
Document Type and Number:
WIPO Patent Application WO/2023/135642
Kind Code:
A1
Abstract:
When a user secret key SKΓ has been generated using a secret key MSK for attribute-based encryption and an attribute set Γ corresponding to a decryptability condition L, an encryption unit (403) of an encryption device (400) generates a key K and ciphertext P corresponding to the key K by encrypting the decryptability condition L using, as a cipher key for the attribute-based encryption, a key PK comprising a public key MPK corresponding to the secret key MSK, and a public key PQCPK for post-quantum cryptography, generates K' and P'-D by representing a portion in which the decryptability condition L is encrypted on the basis of a secret value within the ciphertext P and a portion in which the shared secret value is encrypted within the ciphertext P by P-D and P-SS, respectively, and randomizing the key K and P-D using random numbers R, and generates ciphertext C by encrypting data comprising P-D and the random numbers R using the public key PQCPK. P-SS, P'-D, and K' are decryptability verification parameters corresponding to the user secret key SKΓ.
Inventors:
KAWAI YUTAKA (JP)
Application Number:
PCT/JP2022/000537
Publication Date:
July 20, 2023
Filing Date:
January 11, 2022
Export Citation:
Assignee:
MITSUBISHI ELECTRIC CORP (JP)
International Classes:
G09C1/00; H04L9/08; H04L9/14
Domestic Patent References:
| WO2017203743A1 | 2017-11-30 |
Other References:
MIYAZAWA. TOMOKI ET AL.: "Semi-Adaptively Secure Inner-Product Encryption from Lattices", IPSJ TECHNICAL REPORT: COMPUTER SECURITY (CSEC), vol. 2019-CSEC-87, no. 1, 26 November 2019 (2019-11-26), pages 1 - 8, XP009547741
TOMMASO GAGLIARDONI ; JULIANE KRMER ; PATRICK STRUCK: "Quantum Indistinguishability for Public Key Encryption", IACR, INTERNATIONAL ASSOCIATION FOR CRYPTOLOGIC RESEARCH, 19 February 2021 (2021-02-19), International Association for Cryptologic Research , pages 1 - 39, XP061052147
TOMMASO GAGLIARDONI ; JULIANE KRMER ; PATRICK STRUCK: "Quantum Indistinguishability for Public Key Encryption", IACR, INTERNATIONAL ASSOCIATION FOR CRYPTOLOGIC RESEARCH, 19 February 2021 (2021-02-19), International Association for Cryptologic Research , pages 1 - 39, XP061052147
Attorney, Agent or Firm:
CROSS-BORDER PATENT FIRM (JP)
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