Koga Hiroki

Affiliation
Faculty of Engineering, Information and Systems
Official title
Professor
Sex
Male
Research fields
Theory of informatics
Research keywords
Information Theory
Information Security
Data compression
Research projects
電子指紋符号における不正者全員を特定する頑健なアルゴリズムの構築と同時容量の導出2018 -- 2020古賀 弘樹Japan Society for the Promotion of Science/Grant-in-Aid for Scientific Research(C)3,900,000Yen
不正者全員を特定できる電子指紋符号の容量公式の導出および特定アルゴリズムの開発2014 -- 2016古賀 弘樹Japan Society for the Promotion of Science/基盤研究(C)4,030,000Yen
Study on Visual Cryptology -- (current)/
Study on the Shannon Theory -- (current)/
不正者全員を特定可能な電子指紋符号の構成法とその性能解析2011 -- 2013Japan Society of for the Promotion of Science/基盤研究(C)2,860,000Yen
確率的符号器をもつ情報理論的に安全な暗号システムにおける符号化定理2008 -- 2010Japan Society of for the Promotion of Science/基盤研究(C)4,030,000Yen
計算量的に効率のよい秘密分散法の実現に関する研究                2005 -- 2007Japan Society of for the Promotion of Science/若手研究(B)3,500,000Yen
最適性をもつ視覚復号型秘密分散法の代数的な構成法に関する研究2004 -- (current)Japan Society of for the Promotion of Science/若手研究(B)1,600,000Yen
一般情報源を一様乱数に変換する方法およびその暗号への適用に関する研究2002 -- (current)Japan Society of for the Promotion of Science/若手研究(B)2,100,000Yen
一般情報源をもつシャノンの暗号システムに対する符号化定理に関する研究2000 -- (current)Japan Society of for the Promotion of Science/奨励研究(A)1,100,000Yen
Academic background
1988-04 -- 1990-03The University of Tokyo Faculty of Engineering 計数工学科
1990-04 -- 1992-03The University of Tokyo Graduate School, Division of Engineering 計数工学専攻 修士課程
1992-04 -- 1995-03The University of Tokyo 大学院工学系研究科 計数工学専攻 博士課程
Degree
1995-03博士(工学)The University of Tokyo
Academic societies
-- (current)Institute of Electrical and Electronics Engineers (IEEE)
-- (current)THE INSTITUTE OF ELECTRONICS, INFORMATION AND COMMUNICATION ENGINEERS.
Honors & Awards
2013-05喜安善市賞
2013-05Paper Award
2001SITA2000奨励賞
19981998年暗号と情報セキュリティシンポジウム論文賞
Articles
  • シェアの回転により複数の秘密画像を復元できる視覚暗号の最適な構成法
    古賀 弘樹; 関根 恭平
    信学技報 IT2020-131, 2021-03
  • 視覚暗号の最近の進歩
    古賀 弘樹
    信学技報 IT2020-25, 2020-12
  • An Ideal Secret Sharing Scheme Realizing an Access Structure Based on a Finite Projective Plane of Order 3
    Koga Hiroki; Okawa Yohei
    Proceedings of 2020 IEEE ISIT/pp.852-855, 2020-10
  • New Constructions of an Evolving 2-Threshold Scheme Based on Binary or D-ary Prefix Codes
    Koga Hiroki; Okamura Ryo
    Proceedings of ISITA 2020/pp.432-436, 2020-10
  • Optimal Basis Matrices of a Visual Cryptography Scheme with Meaningful Shares and Analysis of Its Security
    Koga Hiroki
    Proceedings of 2020 ISITA 2020/pp.422-426, 2020-10
  • Coding Theorems on the Simple Capacity for Digital Fingerprinting Codes
    Koga Hiroki
    Proceedings of 2020 ISITA 2020/pp.61-65, 2020-10
  • A Construction of the (4; n)-Threshold Visual Cryptography Scheme Using a 3-Design
    Koutaro Okada; Hiroki Koga
    IEICE Proceeding Series/(55)/pp.223-227, 2018
  • A Construction of Secret Sharing Schemes with Threshold 3 for Countably Infinite Participants
    Taksahi Hisatome; Hiroki Koga
    IEICE Proceeding Series/(55)/pp.513-513, 2018
  • A Higher Order Analysis of the Joint Capacity of Digital Fingerprinting Codes against the Interleaving Attack
    Koga Hiroki
    Proceedings of 2016 ACM Workshop on Information Hiding and Multimedia Security/pp.23-28, 2016-06
  • New Coding Theorems for Fixed-Length Source Coding and Shannon's Cipher System with a General Source
    Koga Hiroki
    Proceedings of 2008 International Symposium on Information Theory, 2008-12
  • New Fundamental Properties on a Secret-key Cryptosystem under Guessing Secrecy Criteria
    Kamiya Shota; Koga Hiroki
    PROCEEDINGS OF 2016 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS (ISITA 2016)/pp.345-349, 2016
  • On a partition of a finite set and its relationships to encoding tasks and the Rényi entropy
    Koga Hiroki
    Proceedings of 2015 IEEE International Symposium on Information Theory/pp.1452-1455, 2015-06
  • A (K, n)-Threshold Scheme with Detectability of All the Cheaters Based on a Certain Majority Rule
    島崎 憲明; 古賀 弘樹
    IEICE technical report. Information theory/114(224)/pp.19-24, 2014-09
  • Four Limits in Probability for Use in Information Theory:- A Brief Introduction to Information-Spectrum Methods with Four Limits -
    古賀 弘樹
    IEICE Fundamentals Review/8(1)/pp.4-14, 2014
  • On the FF Code With the Optimality on both the Redundancy and the Coding Rate
    有村 光晴; 古賀 弘樹; 岩田 賢一
    IEICE technical report. Information theory/112(382)/pp.71-76, 2013-01
  • Four Limits in Probability and Their Operational Meanings in Information Theory
    古賀 弘樹
    IEICE technical report. Information theory/113(483)/pp.119-126, 2014-03
  • A Construction of an Efficient Linear Ramp Threshold Secret Sharing Scheme Using an LT code
    坂下 光輝; 古賀 弘樹; 本庄 俊太郎
    IEICE technical report. Information theory/113(483)/pp.193-200, 2014-03
  • Construction of a Strongly Secure Ramp Secret Sharing Scheme Using the MRD Code and Analysis of its Security
    本庄 俊太郎; 古賀 弘樹; 坂下 光輝
    IEICE technical report. Information theory/113(483)/pp.201-207, 2014-03
  • Coding Theorems for Shannon's Cipher System under Two New Secrecy Criteria
    菊池 駿; 古賀 弘樹
    IEICE technical report. Information theory/113(483)/pp.261-268, 2014-03
  • On the relationship between the redundancy and the coding rate of FF codes
    有村 光晴; 古賀 弘樹; 岩田 賢一
    IEICE technical report. Information theory/112(58)/pp.7-12, 2012-05
  • A Secret Sharing Scheme Based on a Two-Dementional Code with Decodability by Mobile Phones
    本庄 俊太郎; 古賀 弘樹
    IEICE technical report. Information theory/112(58)/pp.35-40, 2012-05
  • A Tracing Algorithm for the Boneh-Shaw Code under a Probabilistic Attack Model
    金井 紘平; 古賀 弘樹
    IEICE technical report. Information theory/112(124)/pp.7-12, 2012-07
  • On Coding of a Binary Source Based on Source Polarization
    菊池 駿; 古賀 弘樹
    IEICE technical report. Information theory/112(124)/pp.103-108, 2012-07
  • Asymptotic Optimality of Modified Spherical Codes with Scalar Quantizer of Gain for Memoryless Gaussian Source
    Hiroki Koga; Suguru Arimoto
    IEICE Transactions on Fundamentals/E76-A(9)/p.1403-1410, 1993-09
  • On the Asynptotic Behaviors of the Recurcence Time Fidelity Criterian for Discrete Memoryless Sources and Memoryless Gaussian Sources
    Hiroki Koga; Suguru Arimoto
    IEICE Transactions on Fundamentels/E81-A(5)/p.981-986, 1998-06
  • more...
Books
  • Digital transmission of Information
    古賀 弘樹;
    1997-01
  • Information-Spectrum Methods in Information Thoery
    古賀 弘樹
    2003-10
  • 現代数理科学事典
    古賀 弘樹
    岩波書店, 2009-12
  • Elements of Information Theory
    Thomas M. Cover; Joy A. Thomas (山本; 古賀 ; 有村 ; 岩本訳) ; + 古賀...
    共立出版社, 2012-07
  • Coding Theorems on the Worst-Case Redundancy of Fixed-Length Coding for a General Source
    Koga Hiroki; Arimura Mitsuharu; Iwata Ken-ichi
    2011 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY PROCEEDINGS (ISIT)/IEEE/pp.1327-1331, 2011-01
  • A Simple Secret Sharing Scheme Using a Key and its Security against Substitution of Shares
    Koga Hiroki
    2010 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY/IEEE/pp.2483-2487, 2010-01
  • Proposal of an asymptotically contrast-ideal (t, n)-threshold visual secret sharing scheme
    Koga Hiroki; Ueda Etsuyo
    2006 IEEE International Symposium on Information Theory, Vols 1-6, Proceedings/IEEE/pp.912-916, 2006-01
  • New Coding Theorems for Fixed-Length Source Coding and Shannon's Cipher System with a General Source
    Koga Hiroki
    2008 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS, VOLS 1-3/IEEE/pp.250-255, 2008-01
  • A Construction of a Visual Secret Sharing Scheme for Plural Secret Images and its Basic Properties
    Koga Hiroki; Miyata Masayuki
    2008 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS, VOLS 1-3/IEEE/pp.24-29, 2008-01
Conference, etc.
  • Coding Theorems on the Simple Capacity for Digital Fingerprinting Codes
    古賀 弘樹
    Technical Committee on Information Theory/2020-03-10--2020-03-11
  • An Ideal Secret Sharing Scheme Realizing an Access Structure Based on a Projective Plane of Order 3
    古賀 弘樹
    The 42nd Symposium on Information Theory and Its Applications/2019-11-26--2019-11-29
  • Optimal Construction of the Basis Matrices of an Extended Visual Cryptography Scheme Using Integer Programming
    古賀 弘樹
    The 42nd Symposium on Information Theory and Its Applications/2019-11-26--2019-11-29
  • A Construction of the (4; n)-Threshold Visual Cryptography Scheme Using a 3-Design
    Okada Koutaro; Koga Hiroki
    15th International Symposium on Information Theory and its Applications (ISITA)/2018-10-28--2018-10-31
  • A Lower Bound on the Joint Capacity of Digital Fingerprinting Codes Using Score Functions Based on Log-Likelihood Ratio
    Koga Hiroki
    IEEE International Symposium on Information Theory (ISIT)/2018-06-17--2018-06-22
  • 数理計画法を用いた視覚暗号の基本行列の2種類の最適化について
    Koga Hiroki
    第39回情報理論とその応用シンポジウム/2016-12-13--2016-12-16
  • BIBDを用いたプログレッシブ型(3,n)-視覚暗号の構成とその最適性
    Koga Hiroki
    電子情報通信学会情報理論研究会/2017-05-22--2017-05-23
  • 平文と鍵の推測確率を考慮した共通鍵暗号システムの基本的性質
    Koga Hiroki
    電子情報通信学会情報理論研究会/2016-03-10--2016-03-11
  • 一般のアクセス構造に対する整数計画法を用いた最適な視覚復号型秘密分散法の構成とその応用
    Koga Hiroki
    電子情報通信学会情報理論研究会/2016-05-19--2016-05-20
  • 意図されないメッセージに対する秘匿性を考慮したインデックス符号
    Koga Hiroki
    電子情報通信学会情報理論研究会/2017-03-09--2017-03-10
  • JPEG画像の消失部分を復元できる電子透かしの提案と性能評価
    古賀 弘樹
    電子情報通信学会情報理論研究会/2015-09-04--2015-09-04
  • 複数のしきい値型アクセス構造に基づく視覚復号型秘密分散法の提案とその拡張
    西住空也; 古賀 弘樹
    電子情報通信学会情報理論研究会/2015-07-13--2015-07-14
  • 連続分布に基づき符号語が生成される電子指紋符号の容量の下界について
    古賀 弘樹
    電子情報通信学会情報理論研究会/2015-05-21--2015-05-22
  • Evaluation of the Joint Capacity of Digital Fingerprinting Codes against the Interleaving Attack
    古賀 弘樹; 板橋薫
    電子情報通信学会情報理論研究会/2016-03-10--2016-03-11
  • On the Achievable Rate Region in the Optimistic Sense for Independent Coding of Two Correlated General Sources
    古賀 弘樹
    電子情報通信学会情報理論研究会/2011-09-29--2011-09-30
  • Coding Theorems on the Worst-Case Redundancy of Fixed-Length Coding for a General Source
    Koga Hiroki; Arimura Mitsuharu; Iwata Ken-ichi
    IEEE International Symposium on Information Theory (ISIT)/2011-07-31--2011-08-05
  • Coding Theorems on the Worst-Case Redundancy of Fixed-Length Coding for a General Source
    Koga Hiroki; Arimura Mitsuharu; Iwata Ken-ichi
    IEEE International Symposium on Information Theory (ISIT)/2011-07-31--2011-08-05
  • A Simple Secret Sharing Scheme Using a Key and its Security against Substitution of Shares
    Koga Hiroki
    2010 IEEE International Symposium on Information Theory/2010-07-13--2010-07-13
Teaching
2021-10 -- 2022-02Oral Presentation Workshop in Intelligent Interaction Technologies IIbUniversity of Tsukuba.
2021-04 -- 2021-08Oral Presentation Workshop in Intelligent Interaction Technologies IIbUniversity of Tsukuba.
2021-10 -- 2022-02Intelligent Interaction Systems Laboratory bUniversity of Tsukuba.
2021-04 -- 2021-08Oral Presentation Workshop in Intelligent Interaction Technologies IaUniversity of Tsukuba.
2021-10 -- 2022-02Oral Presentation Workshop in Intelligent Interaction Technologies IaUniversity of Tsukuba.
2021-10 -- 2022-02Oral Presentation Workshop in Intelligent Interaction Technologies IIaUniversity of Tsukuba.
2021-04 -- 2021-08Oral Presentation Workshop in Intelligent Interaction Technologies IIaUniversity of Tsukuba.
2021-04 -- 2021-08Collaboratory Research Workshop in Intelligent Interaction Technologies IIbUniversity of Tsukuba.
2021-10 -- 2022-02Collaboratory Research Workshop in Intelligent Interaction Technologies IIbUniversity of Tsukuba.
2021-04 -- 2021-08Research in Intelligent Interaction Technologies IUniversity of Tsukuba.
more...
Talks
  • AND攻撃に耐性をもつ結託耐性符号の容量について
    古賀弘樹
    電子情報通信学会 情報理論研究会/2010-03-05
  • 情報スペクトル的手法の発展とその秘密分散法への応用
    古賀弘樹
    電子情報通信学会 情報理論研究会/2009-12-01
Professional activities
2019-06 -- 2021-05IEICE情報理論とその応用サブソサイエティ サブソサイエティ長
2017-05 -- 2019-05IEICE情報理論とその応用サブソサイエティ 副サブソサイエティ長
University Management
2018-04 -- 2020-03専攻学務・カリキュラム副委員長

(Last updated: 2021-06-24)