Organization
School of Computing Associate Professor
Title
Associate Professor
External link
yasunaga kenji
Research Interests
-
Coding Theory
-
Cryptography
Research Areas
-
Informatics / Theory of informatics
Education
-
Osaka University Graduate School of Information Science and Technology Department of Multimedia Engineering
2005.4 - 2008.3
-
Osaka University Graduate School of Information Science and Technology Department of Multimedia Engineering
2003.4 - 2005.3
-
Osaka University School of Engineering Science Department of Information and Computer Sciences
1999.4 - 2003.3
Research History
-
Institute of Science Tokyo School of Computing Associate Professor
2024.10
-
Tokyo Institute of Technology School of Computing Associate Professor
2021.10 - 2024.9
-
Osaka University Graduate School of Information Science and Technology Associate Professor
2018.8 - 2021.9
-
Kanazawa University Faculty of Electrical and Computer Engineering Assistant Professor
2013.1 - 2018.7
-
Institute of Systems, Information Technologies and nanotechnologies (ISIT) Information Security Laboratory Researcher
2011.10 - 2012.12
-
Tokyo Institute of Technology Dept. of Mathematical and Computing Sciences Assistant Professor
2008.10 - 2011.9
-
Kwansei Gakuin University Graduate School of Science and Technology, Research Center for Human Media Post-doctoral fellow
2008.4 - 2008.9
Professional Memberships
-
International Association for Cryptologic Research (IACR)
-
THE INSTITUTE OF ELECTRONICS, INFORMATION AND COMMUNICATION ENGINEERS
Committee Memberships
-
電子情報通信学会 情報理論研究専門委員会，幹事
2025.6 - 2027.6
-
IEEE East Asian School of Information Theory 2024 General Co-Chair
2024.1 - 2024.12
-
International Symposium on Information Theory and Its Applications (ISITA2024), Program Committee.
2024
-
10th ACM ASIA Public-Key Cryptography Workshop (APKC 2023), Program Committee.
2023
-
電子情報通信学会 Special Section on ADiscrete Mathematics and Its Applications 編集委員会 編集幹事
2022.7 - 2023.9
-
第45 回情報理論とその応用シンポジウム(SITA2022), プログラム委員
2022
-
9th ACM ASIA Public-Key Cryptography Workshop (APKC 2022), Program Committee
2022
-
電子情報通信学会 Special Section on ADiscrete Mathematics and Its Applications 編集委員会 編集幹事
2021.8 - 2022.9
-
電子情報通信学会 ソサイエティ論文誌編集委員会 査読委員
2021.6
-
情報処理学会 コンピュータセキュリティ研究運営委員会 専門委員
2021.4
-
電子情報通信学会 Special Section on Information Theory and Its Applications 英文論文 小特集編集委員
2020.12 - 2022.3
-
電子情報通信学会 Special Section on Discrete Mathematics and Its Applications 小特集編集委員会 編集委員
2020.8 - 2021.9
-
電子情報通信学会 情報理論研究専門委員会 専門委員
2020.6 - 2025.6
-
電子情報通信学会 出版委員会 委員
2020.6 - 2022.6
-
The International Symposium on Information Theory and Its Applications (ISITA2020), Program Committee Secretary.
2020
-
誤り訂正符号のワークショップ 2020, 実行委員
2020
-
電子情報通信学会 Special Section on Information Theory and Its Applications 英文論文 小特集編集委員（編集幹事）
2019.11 - 2020.12
-
電子情報通信学会 Special Section on Discrete Mathematics and Its Applications 英文論文 小特集編集委員
2019.8 - 2020.10
-
誤り訂正符号のワークショップ 2019, 実行委員
2019
-
電子情報通信学会 Special Section on Information Theory and Its Applications 英文論文 小特集編集委員（編集幹事）
2018.12 - 2019.12
-
電子情報通信学会 Special Section on Cryptography and Information Security 英文論文 小特集編集委員
2018.11 - 2020.1
-
電子情報通信学会 コンピュテーション研究専門委員会 専門委員
2018.6 - 2024.6
-
第 41 回情報理論とその応用シンポジウム (SITA2018)，プログラム委員会幹事
2018
-
誤り訂正符号のワークショップ 2018，実行委員
2018
-
第 41 回情報理論とその応用シンポジウム (SITA2018)，実行委員
2018
-
電子情報通信学会 Special Section on Discrete Mathematics and Its Applications 英文論文 小特集編集委員（編集幹事）
2017.8 - 2018.9
-
電子情報通信学会 和文論文誌A編集委員会 編集委員
2017.6 - 2021.6
-
電子情報通信学会 情報セキュリティ研究専門委員会 専門委員
2017.6 - 2020.6
-
情報処理学会 コンピュータセキュリティ研究運営委員会 運営委員
2017.4 - 2021.3
-
The 15th International Conference on Applied Cryptography and Network Security (ACNS2017), Organizing Committee
2017
-
誤り訂正符号のワークショップ 2017，実行委員長
2017
-
電子情報通信学会 Special Section on Discrete Mathematics and Its Applications 英文論文 小特集編集委員
2016.9 - 2017.9
-
電子情報通信学会 Special Section on Foundations of Computer Science ~ Developments of the Theory on Algorithms and Computation ~ 英文論文誌 小特集編集委員
2016.1 - 2017.3
-
The Fourth International Symposium on Computing and Networking (CANDAR’16), Program Committee.
2016
-
誤り訂正符号のワークショップ 2016，実行委員
2016
-
第 39 回情報理論とその応用シンポジウム (SITA2016)，実行委員
2016
-
The 3rd International Workshop on Information and Communication Security (WICS’16), Program Committee.
2016
-
第 39 回情報理論とその応用シンポジウム (SITA2016)，プログラム委員.
2016
-
電子情報通信学会 Special Section on Information Theory and Its Applications 英文論文 小特集編集委員
2015.12 - 2016.12
-
電子情報通信学会 Special Section on Discrete Mathematics and Its Applications 英文論文 小特集編集委員
2015.7 - 2016.6
-
電子情報通信学会 Special Section on Foundations of Computer Science ~ Developments of the Theory on Algorithms and Computation ~ 英文論文誌 小特集編集委員
2015.2 - 2016.3
-
電子情報通信学会 Special Section on Cryptography and Information Security 英文論文 小特集編集委員
2015.1 - 2016.1
-
第 38 回情報理論とその応用シンポジウム (SITA2015)，プログラム委員.
2015
-
The 10th International Workshop on Security (IWSEC2015), Program Committee.
2015
-
誤り訂正符号のワークショップ 2015，実行委員
2015
-
LA シンポジウム 2015，実行委員
2015
-
The 9th International Conference on Provable Security (ProvSec2015), Organizing Committee
2015
-
電子情報通信学会 Special Section on Cryptography and Information Security 英文論文 小特集編集委員
2014.1 - 2015.1
-
電子情報通信学会 Special Section on Cryptography and Information Security 英文論文 小特集編集委員
2013.1 - 2014.1
-
電子情報通信学会 Special Section on Cryptography and Information Security 英文論文 小特集編集委員
2012.1 - 2013.1
-
第 35 回情報理論とその応用シンポジウム (SITA2012)，実行委員
2012
-
The 7th International Workshop on Security (IWSEC2012), Organizing Committee
2012
Papers
-
Lower Bounds on Pauli Manipulation Detection Codes Reviewed International journal
Keiya Ichikawa, Kenji Yasunaga
IEEE TRANSACTIONS ON INFORMATION THEORY 72 ( 7 ) 4926 - 4929 2026.7
-
Hardness Amplification beyond Boolean Functions. Reviewed International journal
Nobutaka Shimizu, Kenji Yasunaga
STOC 1278 - 1289 2026
-
Biometrically-independent fuzzy signatures: signing with biometrics without embedding them. Reviewed
Saki Otsuki, Haruna Higo, Toshiyuki Isshiki, Kengo Mori, Satoshi Obana, Hiroto Tamiya, Kenji Yasunaga
EURASIP J. Image Video Process. 2025 ( 1 ) 13 - 13 2025.12
-
Bit-Security Preserving Hardness Amplification Reviewed
Shun Watanabe, Kenji Yasunaga
THEORY OF CRYPTOGRAPHY, TCC 2024, PT II 15365 195 - 223 2025
-
Revisiting Rational Broadcast Protocols. Reviewed International journal
Shunya Otomo, Kenji Yasunaga
CANS 16351 382 - 401 2025
-
Improved bounds for codes correcting insertions and deletions. Reviewed
Kenji Yasunaga
Designs, Codes and Cryptography 92 ( 5 ) 1267 - 1278 2024.5
-
On the Limitations of Computational Fuzzy Extractors. Reviewed
Kenji Yasunaga, Kosuke Yuzawa
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences 106 ( 3 ) 350 - 354 2023.3
-
Fuzzy Signature with Biometric-Independent Verification. Reviewed
Haruna Higo, Toshiyuki Isshiki, Saki Otsuki, Kenji Yasunaga
Proceedings of the 22nd International Conference of the Biometrics Special Interest Group(BIOSIG) 1 - 6 2023
-
Unified View for Notions of Bit Security. Reviewed
Shun Watanabe, Kenji Yasunaga
Advances in Cryptology - ASIACRYPT 2023 - 29th International Conference on the Theory and Application of Cryptology and Information Security 361 - 389 2023
-
Rational Broadcast Protocols Against Timid Adversaries. Reviewed
Keigo Yamashita, Kenji Yasunaga
Decision and Game Theory for Security: 14th International Conference(GameSec) 277 - 293 2023
-
Perfectly Secure Message Transmission against Rational Adversaries Reviewed International journal
Maiki Fujita, Takeshi Koshiba, Kenji Yasunaga
IEEE Journal of Selected Areas in Information Theory 3 ( 2 ) 390 - 404 2022.6
-
Bit Security as Computational Cost for Winning Games with High Probability. Reviewed
Shun Watanabe, Kenji Yasunaga
Advances in Cryptology - ASIACRYPT 2021 - 27th International Conference on the Theory and Application of Cryptology and Information Security 161 - 188 2021
-
Replacing Probability Distributions in Security Games via Hellinger Distance. Reviewed
Kenji Yasunaga
2nd Conference on Information-Theoretic Cryptography(ITC) 17 - 15 2021
-
Practical card-based protocol for three-input majority Reviewed
Kenji Yasunaga
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences 103 ( 11 ) 1296 - 1298 2020.11
-
A Construction of Robustly Reusable Fuzzy Extractors over Blockchains Reviewed
Kodai Sato, Kenji Yasunaga, Toru Fujiwara
Proceedings of 2020 International Symposium on Information Theory and its Applications, ISITA 2020 353 - 357 2020.10
-
On the List Decodability of Insertions and Deletions Reviewed
Tomohiro Hayashi, Kenji Yasunaga
IEEE Transactions on Information Theory 66 ( 9 ) 5335 - 5343 2020.9
-
Error Correction by Structural Simplicity: Correcting Samplable Additive Errors Reviewed
Kenji Yasunaga
Computer Journal 62 ( 9 ) 1265 - 1276 2019.9
-
Perfectly Secure Message Transmission Against Independent Rational Adversaries. Reviewed
Kenji Yasunaga, Takeshi Koshiba
In Proceedings of the 10th Conference on Decision and Game Theory for Security (GameSec 2019), Lecture Notes in Computer Science 11836 LNCS 563 - 582 2019
-
On the List Decodability of Insertions and Deletions Reviewed
Tomohiro Hayashi, Kenji Yasunaga
IEEE International Symposium on Information Theory - Proceedings 2018-June 86 - 90 2018.8
-
Repeated games for generating randomness in encryption Reviewed
Kenji Yasunaga, Kosuke Yuzawa
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E101A ( 4 ) 697 - 703 2018.4
-
Perfectly Secure Message Transmission Against Rational Timid Adversaries. Reviewed
Maiki Fujita, Kenji Yasunaga, Takeshi Koshiba
In Proceedings of the 9th Conference on Decision and Game Theory for Security (GameSec 2018), Lecture Notes in Computer Science 11199 LNCS 127 - 144 2018
-
Rational proofs against rational verifiers Reviewed
Keita Inasawa, Kenji Yasunaga
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E100A ( 11 ) 2392 - 2397 2017.11
-
General Constructions of Rational Secret Sharing with Expected Constant-Round Reconstruction Reviewed
Akinori Kawachi, Yoshio Okamoto, Keisuke Tanaka, Kenji Yasunaga
Computer Journal 60 ( 5 ) 711 - 728 2017.4
-
Public-key encryption with lazy parties Reviewed
Kenji Yasunaga
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E99A ( 2 ) 590 - 600 2016.2
-
Error-correcting codes against chosen-codeword attacks Reviewed
Kenji Yasunaga
In Proceedings of the 9th International Conference on Information Theoretic Security (ICITS 2016), Lecture Notes in Computer Science 10015 LNCS 177 - 189 2016
-
Post-challenge leakage resilient public-key cryptosystem in split state model Reviewed
Eiichiro Fujisaki, Akinori Kawachi, Ryo Nishimaki, Keisuke Tanaka, Kenji Yasunaga
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E98A ( 3 ) 853 - 862 2015.3
-
Randomness leakage in the KEM/DEM framework? Reviewed
Hitoshi Namiki, Keisuke Tanaka, Kenji Yasunaga
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E97-A ( 1 ) 191 - 199 2014.1
-
Correction of samplable additive errors Reviewed
Kenji Yasunaga
IEEE International Symposium on Information Theory - Proceedings 1066 - 1070 2014
-
List decoding of reed-muller codes based on a generalized plotkin construction Reviewed
Kenji Yasunaga
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E96-A ( 7 ) 1662 - 1666 2013.7
-
Leakage-resilience of stateless/stateful public-key encryption from hash proofs Reviewed
Manh Ha Nguyen, Kenji Yasunaga, Keisuke Tanaka
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E96-A ( 6 ) 1100 - 1111 2013.6
-
Preventing abuse of cookies stolen by XSS Reviewed
Hiroya Takahashi, Kenji Yasunaga, Masahiro Mambo, Kwangjo Kim, Heung Youl Youm
Proceedings - 2013 8th Asia Joint Conference on Information Security, AsiaJCIS 2013 85 - 89 2013
-
Game-theoretic security for bit commitment Reviewed
Haruna Higo, Keisuke Tanaka, Kenji Yasunaga
In Proceedings of the 8th International Workshop on Security (IWSEC 2013), Lecture Notes in Computer Science 8231 LNCS 303 - 318 2013
-
Leakage-resilience of stateless/stateful public-key encryption from hash proofs Reviewed
Manh Ha Nguyen, Keisuke Tanaka, Kenji Yasunaga
In Proceedings of the 17th Australasian Conference on Information Security and Privacy (ACISP 2012), Lecture Notes in Computer Science 7372 208 - 222 2012
-
Public-key encryption with lazy parties Reviewed
Kenji Yasunaga
In Proceedings of the 8th Conference on Security and Cryptography for Networks (SCN 2012), Lecture Notes in Computer Science 7485 LNCS 411 - 425 2012
-
A game-theoretic perspective on oblivious transfer Reviewed
Haruna Higo, Keisuke Tanaka, Akihiro Yamada, Kenji Yasunaga
In Proceedings of the 17th Australasian Conference on Information Security and Privacy (ACISP 2012), Lecture Notes in Computer Science 7372 29 - 42 2012
-
Weak Oblivious Transfer from Strong One-Way Functions Reviewed
Keisuke Tanaka, Akihiro Yamada, Kenji Yasunaga
In Proceedings of the 5th International Conference on Provable Security (ProvSec 2011), Lecture Notes in Computer Science 6980 34 - 51 2011
-
Randomness Leakage in the KEM/DEM Framework Reviewed
Hitoshi Namiki, Keisuke Tanaka, Kenji Yasunaga
In Proceedings of the 5th International Conference on Provable Security (ProvSec 2011), Lecture Notes in Computer Science 6980 309 - + 2011
-
Leakage-resilient CCA2 public-key encryption from 4-wise independent hash functions Reviewed
Manh Ha Nguyen, Kenji Yasunaga, Keisuke Tanaka
In Proceedings of the 2011 International Conference on Advanced Technologies for Communications (ATC/REV 2011) 14 - 17 2011
-
On correctable errors of binary linear codes Reviewed
Kenji Yasunaga, Toru Fujiwara
IEEE Transactions on Information Theory 56 ( 6 ) 2537 - 2548 2010.6
-
Uncorrectable Errors of Weight Half the Minimum Distance for Binary Linear Codes Reviewed
Kenji Yasunaga, Toru Fujiwara
2008 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY PROCEEDINGS, VOLS 1-6 975 - + 2008
-
Local weight distribution of the (256, 93) third-order binary reed-muller code Reviewed
Kenji Yasunaga, Toru Fujiwara, Tadao Kasami
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E90-A ( 3 ) 698 - 701 2007.3
-
Kenji Yasunaga, Toru Fujiwara
APPLIED ALGEBRA, ALGEBRAIC ALGORITHMS AND ERROR-CORRECTING CODES, PROCEEDINGS 4851 110 - 119 2007
-
Determination of the local weight distribution of binary linear block codes Reviewed
Kenji Yasunaga, Toru Fujiwara
IEEE Transactions on Information Theory 52 ( 10 ) 4444 - 4454 2006.10
-
Relations between the Local Weight Distributions of a Linear Block Code, its Extended Code, and its Even Weight Subcode Reviewed
Kenji Yasunaga, Toru Fujiwara
2005 IEEE International Symposium on Information Theory (ISIT2005) 382 - 386 2005.9
Books
-
暗号理論入門 = Introduction to cryptography
安永, 憲司（ Role： Sole author）
森北出版 2024.8 （ ISBN:9784627084216 ）
MISC
-
Game Theory in Cryptography Invited Reviewed
Kenji Yasunaga
Computer Software 34 ( 1 ) 81 - 92 2017
-
Game-Theoretic Security for Two-Party Protocols.
Haruna Higo, Keisuke Tanaka, Akihiro Yamada, Kenji Yasunaga
IACR Cryptology ePrint Archive 2016 1072 2016
-
AI-2-3 Protocol Security and Game Theory
Yasunaga Kenji
Proceedings of the IEICE Engineering Sciences Society/NOLTA Society Conference 2015 "SS - 36"-"SS-37" 2015.8
-
プロトコルの安全性とゲーム理論
安永憲司
電子情報通信学会大会講演論文集(CD-ROM) 2015 2015
-
Cryptography and game theory Invited
Kenji Yasunaga
Sugar Seminar 53 ( 10 ) 25 - 29 2014.10
-
On the Possibilities and Limitations of Computational Fuzzy Extractors
Kenji Yasunaga, Kosuke Yuzawa
IACR Cryptology ePrint Archive 2014 605 2014
-
情報漏洩や改竄に耐性のある暗号技術に関する研究
安永憲司, 田中圭介, 吉田真紀
電気通信普及財団研究調査報告書(CD-ROM) ( 28 ) 2013
-
Rational Secret Sharing for Non-Simultaneous Channels
KAWACHI Akinori, OKAMOTO Yoshio, TANAKA Keisuke, YASUNAGA Kenji
IEICE technical report. Information theory 112 ( 58 ) 41 - 46 2012.5
-
竹部裕俊, 安永憲司, 田中圭介
第73回全国大会講演論文集 2011 ( 1 ) 437 - 438 2011.3
-
ManhHaNguyen, 安永憲司, 田中圭介
全国大会講演論文集 2011 ( 1 ) 467 - 469 2011.3
-
山田章央, 安永憲司, 田中圭介
第73回全国大会講演論文集 2011 ( 1 ) 469 - 470 2011.3
-
A Unied Framework for Understanding Pseudorandom Constructions from a Coding Theoretic Perspective Invited Reviewed
YASUNAGA Kenji
IEICE ESS Fundamentals Review 5 ( 1 ) 56 - 67 2011
-
Constant-round reconstruction for rational secret sharing
KAWACHI Akinori, OKAMOTO Yoshio, TANAKA Keisuke, YASUNAGA Kenji
IEICE technical report 110 ( 325 ) 15 - 21 2010.11
-
On Randomness Leakage in Public-Key Encryption
NAMIKI Hitoshi, YASUNAGA Kenji, TANAKA Keisuke
IEICE technical report 110 ( 325 ) 23 - 28 2010.11
-
AT-2-4 Reed-Solomon Codes and Pseudorandomness
Yasunaga Kenji
Proceedings of the Society Conference of IEICE 2010 "SS - 49"-"SS-52" 2010
-
Peformance analysis of error correcting codes
YASUNAGA Kenji
IEICE technical report. Theoretical foundations of Computing 108 ( 443 ) 33 - 33 2009.2
-
On Distance Distribution of a Reed-Solomon-like Code for Network Coding
TOMINAGA Masafumi, YASUNAGA Kenji, FUJIWARA Toru
IEICE technical report 108 ( 158 ) 7 - 10 2008.7
-
A Lower Bound on the Number of Uncorrectable Errors of Weight Half the Minimum Distance
YASUNAGA Kenji, FUJIWARA Toru
IEICE technical report 107 ( 501 ) 51 - 56 2008.2
-
A Lower Bound on the Number of Uncorrectable Errors of Weight Half the Minimum Distance
YASUNAGA Kenji, FUJIWARA Toru
IEICE technical report 107 ( 503 ) 51 - 55 2008.2
-
A Lower Bound on the Number of Uncorrectable Errors of Weight Half the Minimum Distance
YASUNAGA Kenji, FUJIWARA Toru
IEICE technical report 107 ( 499 ) 51 - 56 2008.2
-
Error correction/detection using double encoding in digital watermarking
LIU Tingting, YASUNAGA Kenji, FUJIWARA Toru
29 ( 2 ) 565 - 568 2006.11
-
Correctable Errors of Weight Half the Minimum Distance for the First-Order Reed-Muller Codes
YASUNAGA Kenji, FUJIWARA Toru
29 ( 1 ) 5 - 8 2006.11
-
Local Weight Distribution of the (256, 93) Third-Order Binary Reed-Muller Code
YASUNAGA Kenji, FUJIWARA Toru, KASAMI Tadao
IEICE technical report 106 ( 58 ) 31 - 36 2006.5
-
Relations among the Local Weight Distributions of a Linear Block Code, Its Extended Code and Its Even Weight Subcode
YASUNAGA Kenji, FUJIWARA Toru
27 ( 2 ) 559 - 562 2005.12
-
Improvement of the Seguin Lower Bound Using the Local Weight Distribution
YASUDA Takahiro, YASUNAGA Kenji, FUJIWARA Toru
28 ( 2 ) 435 - 438 2005.11
-
The Local Weight Distributions of Transitive Invariant Codes and Their Punctured Codes
Yasunaga Kenji, Fujiwara Toru
IEICE technical report. Information theory 105 ( 84 ) 7 - 12 2005.5
-
Fujiwara Toru, Yasunaga Kenji
RIMS Kokyuroku 1420 150 - 162 2005.4
-
YASUNAGA Kenji, FUJIWARA Toru
IEICE technical report. Information theory 104 ( 229 ) 7 - 12 2004.7
-
YASUNAGA Kenji, FUJIWARA Toru
IEICE technical report. Information theory 103 ( 308 ) 37 - 41 2003.9
Presentations
-
多項式時間制限通信路に対する公開鍵誤り訂正方式の構成法
角田道映, 安永憲司
2025 年暗号と情報 セキュリティシンポジウム(SCIS2025) 2025.1
-
検出回避攻撃者に対する定数ラウンドコンセンサスプロトコル
園部凌平, 大友駿也, 安永憲司
2025 年暗号と情報セキュリティシンポジウム(SCIS2025) 2025.1
-
鍵準同型擬似ランダム関数を用いた鍵準同型署名の構成に向けて
渡邉耀仁, 安永憲司
2025 年暗号と情報セキュリティシンポジウム(SCIS2025), 2025.1
-
パウリ操作検知符号の弱安全性について
市川景也, 安永憲司
025 年暗号と情報セキュリティシンポ ジウム(SCIS2025) 2025.1
-
変造不可能ファジー抽出器の安全性に関する考察
津田昂樹, 安永憲司
025 年暗号と情報セキュリ ティシンポジウム(SCIS2025) 2025.1
-
安永憲司
電子情報通信学会大会講演論文集(CD-ROM) 2015.8
-
安永憲司, 田中圭介, 吉田真紀
電気通信普及財団研究調査報告書(CD-ROM) 2013.12
-
安永憲司
情報理論とその応用シンポジウム予稿集(CD-ROM) 2012.12
-
安永憲司
情報処理学会シンポジウムシリーズ(CD-ROM) 2012.10
-
安永憲司
電子情報通信学会大会講演論文集 2010.8
-
ネットワーク符号化におけるリード・ソロモン型符号の基底選択と重み構造について
富永昌文, 安永憲司, 藤原融
情報理論とその応用シンポジウム予稿集(CD-ROM) 2008.9
-
On Distance Distribution of a Reed-Solomon-like Code for Network Coding
富永昌文, 安永憲司, 藤原融
電子情報通信学会技術研究報告 2008.7
-
LIU Tingting, 安永憲司, 藤原融
情報理論とその応用シンポジウム予稿集 2006.11
-
安田隆広, 安永憲司, 藤原融
情報理論とその応用シンポジウム予稿集 2005.11
Awards
-
Outstanding Paper Award
2018.10 GameSec 2018
Maiki Fujita, Kenji Yasunaga, Takeshi Koshiba
-
Kasami Award
2008
Kenji Yasunaga
-
Society of Information Theory and Its Applications (SITA) Encouragement Award
2007
Kenji Yasunaga
Research Projects
-
情報・計算・暗号の融合によるセキュリティ定量化理論の深化
Grant number：26H02489 2026.4 - 2030.3
日本学術振興会 科学研究費助成事業 基盤研究(A)
安永 憲司
Grant amount：\41730000 （ Direct Cost: \32100000 、 Indirect Cost：\9630000 ）
-
2024.10 - 2029
科学技術振興機構 戦略的な研究開発の推進 戦略的創造研究推進事業 CRONOS(情報通信科学・イノベーション創出基盤事業)
泉 泰介
サイバー空間を形成する多様な系・サービスは本質的に自律分散的であり、その安全かつ公正な制御は重要な技術的要請である。本研究は特に「公正な割り当てと合意の自律分散的制御」を目的としたアルゴリズム研究に取り組む。ユーザーの利己性・動的変化といった多種複雑なダイナミズムが存在する自律分散環境下において公正な割り当て・合意を達成するアルゴリズム設計の方法論を確立することを目指す。
-
Foundations of Secure Distributed Quantum Computing on Medium-Scale Quantum Computers
Grant number：24H00071 2024.4 - 2029.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (S)
Grant amount：\203450000 （ Direct Cost: \156500000 、 Indirect Cost：\46950000 ）
-
New theory for security analysis: from information inequality to computational inequality
Grant number：23K17455 2023.6 - 2026.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Pioneering)
Grant amount：\26000000 （ Direct Cost: \20000000 、 Indirect Cost：\6000000 ）
-
Complexity of Code Construction Problems
Grant number：23K18460 2023.6 - 2026.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory)
Grant amount：\6500000 （ Direct Cost: \5000000 、 Indirect Cost：\1500000 ）
-
Foundations of Security Quantification by Integrating Information, Computation, and Cryptography Theories
Grant number：23H00468 2023.4 - 2027.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
Grant amount：\46930000 （ Direct Cost: \36100000 、 Indirect Cost：\10830000 ）
-
Construction of Quantum Computaional Infrastracture towards Quantum Information Society
Grant number：21H04879 2021.4 - 2026.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
Grant amount：\41470000 （ Direct Cost: \31900000 、 Indirect Cost：\9570000 ）
-
Exploring the Limitations of Deletion Codes
Grant number：18K11159 2018.4 - 2023.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
Yasunaga Kenji
Grant amount：\4160000 （ Direct Cost: \3200000 、 Indirect Cost：\960000 ）
Focusing on error correctability of list decoding for insertions and deletions, we derived a bound generalizing the Johnson bound for ordinary symbol errors to the Levenshtein distance. The bound implies that the correctability for insertions is superior to deletions in list decoding. Also, we construct a code to achieve the correctability of this bound based on concatenated codes. In addition, based on the bound for list decodability, we derived a bound representing the trade-off between insertion/deletion correctability and coding rate by a probabilistic argument. This bound is superior to the existing ones for binary codes.
-
Constructions for Cryptographic Primitives with Incentives
Grant number：17H01695 2017.4 - 2021.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Tanaka Keisuke
Grant amount：\15860000 （ Direct Cost: \12200000 、 Indirect Cost：\3660000 ）
We conducted a survey and research on incentive design techniques. Through detailed surveys and comparisons of techniques, we attempted to design models and techniques for incentive-based digital signatures and authentication. In particular, we focused on an element called Secure Message Transmission (SMT), which is closely related to these elements, and showed that even if multiple communication channels are all controlled by an adversary, communication can be performed securely when a rational adversary is considered. In addition, we conducted a survey and research on blockchain. In particular, we returned to the origin of proof-of-work and examined the situation where a time and memory gap occurs between the prover and the verifier.
-
Interpolative Expansion of Quantum Protocol Theory
Grant number：16H01705 2016.4 - 2021.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
Takeshi Koshiba
Grant amount：\41730000 （ Direct Cost: \32100000 、 Indirect Cost：\9630000 ）
The computational power of the DQC1 model, which is a formalization of non-universal quantum computation with initialization-hard quantum states, is shown to be superior to classical computation. Many quantum distributed algorithms are developed. Under the standard model for distributed algorithms, efficient quantum protocols for several fundamental problems such as the shortest path problem. Secure quantum delegated computation cannot achieve the perfect security for classical clients. By introducing the notion of rewards in quantum computations, classical verification of having the quantum power of the server is affirmatively settled. This is a game-theoretic solution and gives a novel method in quantum computation.
-
符号理論における計算限界の解明
Grant number：15H00851 2015.4 - 2017.3
日本学術振興会 科学研究費助成事業 新学術領域研究(研究領域提案型)
安永 憲司
Grant amount：\4550000 （ Direct Cost: \3500000 、 Indirect Cost：\1050000 ）
本研究は、誤り訂正符号技術の計算限界を解明することを目的としている。特に、計算量制限通信路を考え、計算限界の解明を目指す。
計算量制限通信路は、Lipto (1994) が導入した概念であり、彼は二元対称通信路向けの符号を計算量制限通信路向けに変換する方法を示した。具体的には、送受信者間でランダムな鍵を共有する設定を考え、その鍵を利用して、送信符号語の位置をランダムに置換し、ランダムマスクでその情報を隠すという方法を提案している。この方法により、通信路において任意の誤りが発生したとしても、その誤りの位置はランダムに置換されるため、ランダム誤りが挿入されたとみなすことができ、二元対称通信路向けの符号で訂正することが可能となる。
Lipton の手法では、秘密鍵が１回限りしか有効でないという問題がある。つまり、複数回の誤り訂正を行うためには、その数に合わせた数の鍵を共有する必要がある。この状況は、秘密鍵暗号における使い捨て鍵暗号と同じである。使い捨て鍵暗号は、十分な秘匿性を達成できるが、複数回の通信のためにはその数に合わせた数の鍵を共有する必要がある。
利用回数に制限のある使い捨て鍵暗号に対し、現代的な秘密鍵暗号では、一つの鍵を共有することで任意の回数の暗号化通信を保証する仕組みを持っている。さらに、攻撃者が暗号化関数や復号関数を利用できるような状況を考慮したより強力な安全性を考え、現在ではそのような安全性が標準的とも考えられている。
本研究では、Lipton 方式を使い捨て鍵による誤り訂正符号と考え、その安全性を現代的な暗号技術と同等に高めた方式を構築した。具体的には、Guruswami と Smith (2016) の方式を、秘密鍵設定における誤り訂正符号とみなし、その方式に対し、通信路が符号化関数と復号関数を利用できたとしても問題なく誤り訂正ができることを証明した。 -
計算構造制限下での暗号技術の限界解明
Grant number：25106509 2013.4 - 2015.3
日本学術振興会 科学研究費助成事業 新学術領域研究(研究領域提案型)
安永 憲司
Grant amount：\4030000 （ Direct Cost: \3100000 、 Indirect Cost：\930000 ）
本研究では、計算構造の制限下における暗号技術の存在限界を解明することを目的としている。
情報セキュリティの完全性に関わる暗号技術として、誤り訂正符号がある。データを通信・保存して取り出す際に、データの誤りを検出・訂正する技術である。ブラックボックス構成による存在限界が明らかになっていなかった誤り訂正符号に着目し、その限界を明らかにすることを目指した。特に、最悪ケース通信路をより現実的な範囲に限定した、計算量制限通信路に着目し、既存研究で明らかになっていなかった、挿入可能誤り数に制限がない場合の訂正限界の解明を目指した。
まず、擬似ランダムな誤りが挿入される場合は、効率的な誤り訂正が不可能であることがわかった。この議論から、エントロピーが入力長の任意の多項式オーダーであるような比較的小さい誤りであっても、効率的に訂正不可能なものが存在することがわかった。この議論には、一方向性関数の存在を仮定する必要があるが、このような不可能性の議論には一方向性関数の存在性が必要であることも分かった。また、誤りのエントロピーが対数関数より真に大きい程度の、非常に小さい場合であっても、効率的な誤り訂正が望めないこ とを明らかにした。より具体的には、あるオラクルへのアクセスを許す環境において、効率的にサンプル可能であるが、効率的に訂正不可能な誤りが存在することを示した。この結果から、誤りの効率的なサンプル可能性を利用した、誤り訂正符号のブラックボックス構成が不可能であることが明らかになった。この不可能性の結果は、符号化レートがある程度以下の場合の不可能性であったが、それより高い符号化レー トの場合には、より強力な、情報理論的な不可能性を示すことができる。つまり、誤りの効率的なサンプル可能性を利用した符号の構成はすべての符号化レートにおいて不可能であることが明らかになった. -
Deepening Theory of Quantum Protocols
Grant number：24240001 2012.4 - 2016.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
KOSHIBA Takeshi
Grant amount：\36010000 （ Direct Cost: \27700000 、 Indirect Cost：\8310000 ）
We propose a generalized model of quantum interactive proof systems and show the existence of complete problems and a quantum version of Babai's collapse theorem. We construct efficient quantum algorithms for matrix multiplication of semi-rings and for finding triangles in graphs and develop their analysis to obtain their quantum distribution protocols. In ancilla-driven model where computation systems and measurement systems are separable, we show that quantum blind computation is achievable. We characterize a classical computational complexity class AWPP, which corresponds to a quantum computational complexity class BQP, by using the notion of post-selection. We give a natural reason why AWPP is the tightest upper bound of BQP and develop a quantum complexity theoretic approach to the study of AWPP.
-
Game Theoretic Studies on Cryptographic Protocols
Grant number：23500010 2011.4 - 2015.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
TANAKA Keisuke, YASUNAGA Kenji
Grant amount：\5070000 （ Direct Cost: \3900000 、 Indirect Cost：\1170000 ）
We characterize the properties of two-message oblivious transfer protocols by using a game-theoretic concept. Specifically, we present a single two-player game for two-message oblivious transfer in the game-theoretic framework, where it captures the cryptographic properties of correctness and privacy in the presence of malicious adversaries.
In addition we also focus on bit commitment, and study it from a perspective of game theory. In a similar manner to the work on oblivious transfer, we consider bit commitment in the malicious model. In order to naturally capture the security properties of bit commitment, we characterize them with a single game where both parties are rational. In particular, we define a security notion from a game theoretic viewpoint, and prove the equivalence between it and the standard security notion. -
Randomness and Structure in Error-Correcting Codes
Grant number：23700010 2011 - 2013
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
YASUNAGA Kenji
Grant amount：\3640000 （ Direct Cost: \2800000 、 Indirect Cost：\840000 ）
We have introduced samplable additive-error channels, and studied the possibilities and limitations of error correction in the channels. "Samplable" means that the errors are efficiently computable, and "additive" means that the errors are added to input codewords without the knowledge of the code or the codewords. If samplable distributions form linear subspaces, we can correct the errors by linear codes. In the situations relativized by oracles, there are samplable errors with low entropy for which no efficient syndrome decoding exists. If samplable distributions are of small-bias, there is a relation between the magnitude of the bias and the information rate on which the errors are correctable.
-
Constructions of Error-Correcting Codes Based on Pseudorandomness
Grant number：20860079 2008 - 2009
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (Start-up)
Grant amount：\3289000 （ Direct Cost: \2530000 、 Indirect Cost：\759000 ）
It was realized that many pseudorandom objects, such as list-decodable code, pseudorandom generator, and expander graph, have a common structure. Also it was realized that pseudorandom generators for polynomials are equivalent to good error-correcting codes under a certain condition. We generalized a decoding algorithm for codes based on polynomials to be applicable to more general class of codes.