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Combinatorial group-theoretic study on "weak algebras" for advanced cryptosystems and secure computation

Research Project

Project/Area Number 19H01804
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Review Section Basic Section 12040:Applied mathematics and statistics-related
Research InstitutionKyushu University

Principal Investigator

Nuida Koji  九州大学, マス・フォア・インダストリ研究所, 教授 (20435762)

Co-Investigator(Kenkyū-buntansha) 山下 剛  京都大学, 数理解析研究所, 講師 (70444453)
Project Period (FY) 2019-04-01 – 2022-03-31
Project Status Completed (Fiscal Year 2021)
Budget Amount *help
¥17,290,000 (Direct Cost: ¥13,300,000、Indirect Cost: ¥3,990,000)
Fiscal Year 2021: ¥6,110,000 (Direct Cost: ¥4,700,000、Indirect Cost: ¥1,410,000)
Fiscal Year 2020: ¥5,590,000 (Direct Cost: ¥4,300,000、Indirect Cost: ¥1,290,000)
Fiscal Year 2019: ¥5,590,000 (Direct Cost: ¥4,300,000、Indirect Cost: ¥1,290,000)
Keywords完全準同型暗号 / 組合せ論的群論 / 宇宙際Teichmuller理論 / 暗号理論 / 高機能暗号 / 宇宙際Teichmüller理論 / 暗号数理 / 秘密計算
Outline of Research at the Start

現代の暗号分野では、数値を秘匿しつつ任意の演算を可能とする「完全準同型暗号」の研究が進み、プライバシー保護やビッグデータ解析など応用面での期待も高まっている。本研究代表者は、同技術の効率的な構成を可能とする新原理を既に提案しているものの、その実現に必要な諸条件を満たす代数構造の具体的構成にまだ成功していない。本研究ではこの問題に対して、群論、代数学、組合せ論など数学の観点および暗号理論的な安全性解析という両面から解決に取り組む。

Outline of Final Research Achievements

Fully homomorphic encryption (FHE) is a special kind of encryption schemes that enable us to perform arbitrary operations on encrypted data. The existing FHE schemes commonly used some complicated and inefficient operation called "bootstrapping". In order to remove it, the principal researcher in this research has developed a new framework for constructing FHE schemes, but concrete construction of the suitable mathematical object realizing the framework was not achieved. In this research, towards concrete construction of the aforementioned suitable mathematical object, we analized the framework mentioned above more closely, and studied the related mathematical theory.

Academic Significance and Societal Importance of the Research Achievements

完全準同型暗号とは、データを暗号化したままであらゆる演算を行うことのできる特殊な暗号化技術であり、企業秘密情報や個人のプライバシー情報を適切に秘匿したままでデータ利活用を行うプライバシー保護データ解析技術の主要な構成要素技術として期待されている。本研究は、この完全準同型暗号の既存の構成法に共通する複雑な操作を除去して効率性を大きく高めることを目標としており、プライバシー保護データ解析技術の効率化への貢献が期待されるとともに、本研究の過程で整備した種々の数学理論それ自体も学術的に意義深いものと考える。

Report

(4 results)
  • 2021 Annual Research Report   Final Research Report ( PDF )
  • 2020 Annual Research Report
  • 2019 Annual Research Report
  • Research Products

    (9 results)

All 2021 2020 2019 Other

All Int'l Joint Research (1 results) Journal Article (4 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 4 results,  Open Access: 1 results) Presentation (4 results) (of which Int'l Joint Research: 2 results,  Invited: 1 results)

  • [Int'l Joint Research] University of Giessen(ドイツ)

    • Related Report
      2019 Annual Research Report
  • [Journal Article] An elementary linear-algebraic proof without computer-aided arguments for the group law on elliptic curves2021

    • Author(s)
      Koji Nuida
    • Journal Title

      International Journal of Mathematics for Industry

      Volume: - Issue: 01

    • DOI

      10.1142/s2661335221500015

    • NAID

      120007181903

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Locally finite continuations and Coxeter groups of infinite ranks2021

    • Author(s)
      Bernhard Muhlherr, Koji Nuida
    • Journal Title

      Journal of Pure and Applied Algebra

      Volume: 225 Issue: 1 Pages: 106464-106464

    • DOI

      10.1016/j.jpaa.2020.106464

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Towards Constructing Fully Homomorphic Encryption without Ciphertext Noise from Group Theory2020

    • Author(s)
      Koji Nuida
    • Journal Title

      in: Proceedings of International Symposium on Mathematics, Quantum Theory, and Cryptography

      Volume: - Pages: 57-78

    • DOI

      10.1007/978-981-15-5191-8_8

    • ISBN
      9789811551901, 9789811551918
    • Related Report
      2020 Annual Research Report
    • Peer Reviewed
  • [Journal Article] An introduction to $p$-adic Hodge theory for open varieties via syntomic cohomology2019

    • Author(s)
      Go Yamashita
    • Journal Title

      in: Une promenade dans la theorie de Hodge p-adique: des fondements aux developpements recents, Panoramas et Syntheses

      Volume: 54 Pages: 131-157

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed
  • [Presentation] A Motivation of Theta-Link from Hodge-Arakelov Theory2021

    • Author(s)
      Go Yamashita
    • Organizer
      Inter-universal Teichmuller Theory Summit 2021
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Optimal DeepLLL系基底簡約の停止性の証明と計算量評価2021

    • Author(s)
      小田川 拓利, 縫田 光司
    • Organizer
      暗号と情報セキュリティシンポジウム2021(SCIS 2021)
    • Related Report
      2020 Annual Research Report
  • [Presentation] 平方剰余に基づくPrivate Simultaneous Messagesについて2021

    • Author(s)
      品川 和雅, 江利口 礼央, 縫田 光司
    • Organizer
      暗号と情報セキュリティシンポジウム2021(SCIS 2021)
    • Related Report
      2020 Annual Research Report
  • [Presentation] Towards Constructing Fully Homomorphic Encryption without Ciphertext Noise from Group Theory2019

    • Author(s)
      Koji Nuida
    • Organizer
      International Symposium on Mathematics, Quantum Theory, and Cryptography (MQC 2019)
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research / Invited

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Published: 2019-04-18   Modified: 2023-01-30  

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