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Our Researchers

April 7, 2020

Kazuhiko Minematsu

Kazuhiko Minematsu

Security Research Laboratories
Research Fellow
A Study on Block cipher Modes for Encryption and Authentication. 2008 Waseda University

Research area

  • Theory and practice on symmetric-key cryptography


Refereed International Conference

  • Zhenzhen Bao, Jian Guo, Tetsu Iwata, Kazuhiko Minematsu:
    ZOCB and ZOTR: Tweakable Blockcipher Modes for Authenticated Encryption with Full Absorption.
    IACR Transactions on Symmetric Cryptology 2019(2): 1-54 (2019)
  • Akiko Inoue, Tetsu Iwata, Kazuhiko Minematsu, Bertram Poettering:
    Cryptanalysis of OCB2: Attacks on Authenticity and Confidentiality. CRYPTO (1) 2019: 3-31 (BEST PAPER AWARD)
  • Kazuhiko Minematsu, Norifumi Kamiya:
    Symmetric-Key Corruption Detection: When XOR-MACs Meet Combinatorial Group Testing.
    ESORICS (1) 2019: 595-615
  • Rei Ueno, Naofumi Homma, Tomonori Iida, Kazuhiko Minematsu:
    High Throughput/Gate FN-Based Hardware Architectures for AES-OTR. ISCAS 2019: 1-4
  • Kosei Sakamoto, Kazuhiko Minematsu, Nao Shibata, Maki Shigeri, Hiroyasu Kubo, Yuki Funabiki, Andrey Bogdanov, Sumio Morioka, Takanori Isobe:
    Tweakable TWINE: Building a Tweakable Block Cipher on Generalized Feistel Structure. IWSEC 2019: 129-145
  • Akiko Inoue and Kazuhiko Minematsu : Parallelizable Authenticated Encryption with Small State Size.
    SAC 2019 (pre-proceedings)
  • Kazuhiko Minematsu : A Lightweight Alternative to PMAC. SAC 2019 (pre-proceedings)
  • Takanori Isobe and Kazuhiko Minematsu : Plaintext Recovery Attacks against XTS Beyond Collisions.
    SAC 2019 (pre-proceedings)
  • Takanori Isobe, Kazuhiko Minematsu:
    Breaking Message Integrity of an End-to-End Encryption Scheme of LINE. ESORICS (2) 2018: 249-268
  • Kazuhiko Minematsu, Kentarou Sasaki, Yuki Tanaka:
    Count-then-Permute: A Precision-Free Alternative to Inversion Sampling. CT-RSA 2018: 264-278
  • Kazuhiko Minematsu, Tetsu Iwata:
    Cryptanalysis of PMACx, PMAC2x, and SIVx. IACR Transaction on Symmetric Cryptology 2018
  • Ashwin Jha, Sweta Mishra, Eik List, Kazuhiko Minematsu, and Mridul Nandi.
    XHX -- A Framework for Optimally Secure Tweakable Block Ciphers from Classical Block Ciphers and Universal Hashing. LATINCRYPT 2017 (to appear)
  • Tetsu Iwata, Kazuhiko Minematsu, Thomas Peyrin, Yannick Seurin:
    ZMAC: A Fast Tweakable Block Cipher Mode for Highly Secure Message Authentication. CRYPTO 2017
  • Avik Chakraborti, Tetsu Iwata, Kazuhiko Minematsu, Mridul Nandi:
    Blockcipher-Based Authenticated Encryption: How Small Can We Go? CHES 2017: 277-298
  • Tetsu Iwata, Kazuhiko Minematsu:
    Stronger Security Variants of GCM-SIV. IACR Transaction on Symmetric Cryptology 2017
  • Kazuya Imamura, Kazuhiko Minematsu, Tetsu Iwata:
    Integrity Analysis of Authenticated Encryption Based on Stream Ciphers. ProvSec 2016: 257-276
  • Kazuhiko Minematsu:
    Authenticated Encryption with Small Stretch (or, How to Accelerate AERO). ACISP 2016: 347-362
  • Subhadeep Banik, Andrey Bogdanov, Kazuhiko Minematsu:
    Low-area hardware implementations of CLOC, SILC and AES-OTR. HOST 2016: 71-74
  • Kazuhiko Minematsu:
    Efficient Message Authentication Codes with Combinatorial Group Testing. ESORICS 2015: 185-202
  • Kazuhiko Minematsu, Tetsu Iwata:
    Tweak-Length Extension for Tweakable Blockciphers. IMA Int. Conf. 2015: 77-93
  • Yuichi Niwa, Keisuke Ohashi, Kazuhiko Minematsu, Tetsu Iwata:
    GCM Security Bounds Reconsidered. FSE 2015: 385-407
  • Noritaka Yamashita, Kazuhiko Minematsu, Toshihiko Okamura, Yukiyasu Tsunoo:
    A smaller and faster variant of RSM. DATE 2014: 1-6
  • Kazuhiko Minematsu:
    Parallelizable Rate-1 Authenticated Encryption from Pseudorandom Functions. EUROCRYPT 2014: 275-292
  • Tetsu Iwata, Kazuhiko Minematsu, Jian Guo, Sumio Morioka:
    CLOC: Authenticated Encryption for Short Input. FSE 2014: 149-167
  • Kazuhiko Minematsu, Stefan Lucks, Hiraku Morita, Tetsu Iwata:
    Attacks and Security Proofs of EAX-Prime. FSE 2013: 327-347
  • Kazuhiko Minematsu, Stefan Lucks, Tetsu Iwata:
    Improved Authenticity Bound of EAX, and Refinements. ProvSec 2013: 184-201
  • Kazuhiko Minematsu:
    A Short Universal Hash Function from Bit Rotation, and Applications to Blockcipher Modes. ProvSec 2013: 221-238
  • Tetsu Iwata, Keisuke Ohashi, Kazuhiko Minematsu:
    Breaking and Repairing GCM Security Proofs. CRYPTO 2012: 31-49
  • Tomoyasu Suzaki, Kazuhiko Minematsu, Sumio Morioka, Eita Kobayashi:
    TWINE: A Lightweight Block Cipher for Multiple Platforms. Selected Areas in Cryptography 2012: 339-354
  • Tomoyasu Suzaki, Kazuhiko Minematsu, Sumio Morioka, Eita Kobayashi:
    TWINE: A Lightweight, Versatile Block Cipher. ECRYPT Workshop on Lightweight Cryptography 2011.
  • Kazuhiko Minematsu, Tomoyasu Suzaki, Maki Shigeri:
    On Maximum Differential Probability of Generalized Feistel. ACISP 2011: 89-105
  • Kazuhiko Minematsu, Tetsu Iwata:
    Building Blockcipher from Tweakable Blockcipher: Extending FSE 2009 Proposal. IMA Int. Conf. 2011: 391-412
  • Tomoyasu Suzaki, Kazuhiko Minematsu:
    Improving the Generalized Feistel. FSE 2010: 19-39
  • Kazuhiko Minematsu:
    How to Thwart Birthday Attacks against MACs via Small Randomness. FSE 2010: 230-249
  • Kazuhiko Minematsu:
    Beyond-Birthday-Bound Security Based on Tweakable Block Cipher. FSE 2009: 308-326 2007
  • Kazuhiko Minematsu, Toshiyasu Matsushima:
    New Bounds for PMAC, TMAC, and XCBC. FSE 2007: 434-451
  • Kazuhiko Minematsu, Toshiyasu Matsushima:
    Tweakable Enciphering Schemes from Hash-Sum-Expansion. INDOCRYPT 2007: 252-267 2006
  • Kazuhiko Minematsu, Yukiyasu Tsunoo:
    Provably Secure MACs from Differentially-Uniform Permutations and AES-Based Implementations. FSE 2006: 226-241
  • Kazuhiko Minematsu:
    Improved Security Analysis of XEX and LRW Modes. Selected Areas in Cryptography 2006: 96-113 2005
  • Kazuhiko Minematsu, Yukiyasu Tsunoo:
    Hybrid Symmetric Encryption Using Known-Plaintext Attack-Secure Components. ICISC 2005: 242-260
  • Kazuhiko Minematsu, Yukiyasu Tsunoo:
    Expanding Weak PRF with Small Key Size. ICISC 2005: 284-298

International Journal

  • Jooyoung Lee, Atul Luykx, Bart Mennink, Kazuhiko Minematsu.
    Connecting tweakable and multi-key blockcipher security. Design, Codes and Cryptography 2017.
  • Kazuhiko Minematsu:
    Building blockcipher from small-block tweakable blockcipher. Des. Codes Cryptography 74(3): 645-663 (2015)
  • Hayato Kobayashi, Kazuhiko Minematsu, Tetsu Iwata:
    Optimality of Tweak Functions in CLOC. IEICE Transactions 98-A(10): 2152-2164 (2015)
  • Kazuhiko Minematsu, Toshiyasu Matsushima:
    Generalization and Extension of XEX* Mode. IEICE Transactions 92-A(2): 517-524 (2009)
  • Kazuhiko Minematsu, Toshiyasu Matsushima:
    Improved MACs from Differentially-Uniform Permutations. IEICE Transactions 90-A(12): 2908-2915 (2007)
  • Yukiyasu Tsunoo, Etsuko Tsujihara, Maki Shigeri, Hiroyasu Kubo, Kazuhiko Minematsu:
    Improving cache attacks by considering cipher structure. Int. J. Inf. Sec. 5(3): 166-176 (2006)
  • Yukiyasu Tsunoo, Teruo Saito, Maki Shigeri, Hiroyasu Kubo, Kazuhiko Minematsu:
    Shorter bit sequence is enough to break stream cipher LILI-128. IEEE Trans. Information Theory 51(12): 4312-4319 (2005)


  • SCIS* 2019 innovation paper award
  • CRYPTO 2019 Best paper award
  • SCIS* 2018 innovation paper award
  • FSE 2015 Best paper award
  • ProvSec 2016 Best student paper award
  • *
    Symposium on Cryptography and Information Security


  • CRYPTREC Lightweight Cryptography Working Group 2013-2017

Invited Talks

  • An analysis of parallelizable authenticated encryption. Asian Symmetric-key Workshop (ASK) 2018, Kolkata, India.
  • Forgery and Impersonation Attacks against of LINE’s End-to-End Encryption Schemes. Tokyo Crypto Day, 2018 On the security of LINE messaging application (Joint work with Takanori Isobe). Dagstuhl Seminar 2018
  • On randomized encryption beyond IV collision. Early Symmetric-key Conference, Luxemburg, 2017
  • CLOC, SILC and OTR. Recent Advances in Authenticated Encryption, ISI Kolkata, India, 2016
  • On security notions and constructions of authenticated encryption Cryptology Frontier Group, Japan Advanced Institute of Science and Technology, 2015 (in Japanese)
  • Trends and recent results on Symmetric-key cryptography. Waseda University, 2015 (in Japanese)
  • Design tools for blockcipher modes. Denmark Technical University, 2014
  • Efficient Message Authentication Codes with Combinatorial Group Testing. The Fifth Asian Workshop on Symmetric Key Cryptography, ASK 2015, Singapore.
  • Design approaches to efficient blockcipher modes. The Fourth Asian Workshop on Symmetric Key Cryptography, ASK 2014, India.
  • Applications of CBC mode for authentication: CBC-MAC and its variants. Jimbo-cho Crypto workshop 2013 (in Japanese)