Publications

2026

1. IACR CiC

   Generalizing Bit-based Rebound Attacks on AES-like Hashing

   Kodai Taiyama , Ryoma Ito , Kosei Sakamoto , Kazuma Taka , Keita Toyama , and Takanori Isobe

   IACR Communications in Cryptology, 2026

   DOI Bib

   @article{DBLP:journals/cic/TaiyamaISTTI26,
     author = {Taiyama, Kodai and Ito, Ryoma and Sakamoto, Kosei and Taka, Kazuma and Toyama, Keita and Isobe, Takanori},
     title = {Generalizing Bit-based Rebound Attacks on {AES}-like Hashing},
     volume = {3},
     number = {3},
     year = {2026},
     date = {2026-10-26},
     issn = {3006-5496},
     doi = {10.62056/a6y7n5qiu},
     journal = {{IACR} Communications in Cryptology},
     publisher = {International Association for Cryptologic Research}
   }

2025

1. IACR CiC

   Exploring SHA Instructions and Its Application to AES-based Schemes

   Takuro Shiraya , Subhadeep Banik , Tatsuya Ishikawa , Ryoma Ito , Mostafizar Rahman , Kosei Sakamoto , Atsushi Tanaka , Shion Utsumi , and Takanori Isobe

   IACR Commun. Cryptol., 2025

   DOI Bib Code

   @article{DBLP:journals/cic/ShirayaBIIRSTUI25,
     author = {Shiraya, Takuro and Banik, Subhadeep and Ishikawa, Tatsuya and Ito, Ryoma and Rahman, Mostafizar and Sakamoto, Kosei and Tanaka, Atsushi and Utsumi, Shion and Isobe, Takanori},
     title = {Exploring {SHA} Instructions and Its Application to AES-based Schemes},
     journal = {{IACR} Commun. Cryptol.},
     volume = {2},
     number = {3},
     pages = {28},
     year = {2025},
     url = {https://doi.org/10.62056/anxrudy6b},
     doi = {10.62056/ANXRUDY6B},
     timestamp = {Sat, 12 Sep 2026 15:34:09 +0200},
     biburl = {https://dblp.org/rec/journals/cic/ShirayaBIIRSTUI25.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. JISA

   Security analysis of SFrame

   Takanori Isobe , Ryoma Ito , and Kazuhiko Minematsu

   J. Inf. Secur. Appl., 2025

   DOI Bib

   @article{DBLP:journals/istr/IsobeIM25,
     author = {Isobe, Takanori and Ito, Ryoma and Minematsu, Kazuhiko},
     title = {Security analysis of SFrame},
     journal = {J. Inf. Secur. Appl.},
     volume = {89},
     pages = {103958},
     year = {2025},
     url = {https://doi.org/10.1016/j.jisa.2024.103958},
     doi = {10.1016/J.JISA.2024.103958},
     timestamp = {Fri, 14 Feb 2025 20:50:10 +0100},
     biburl = {https://dblp.org/rec/journals/istr/IsobeIM25.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

3. JISA

   On the effects of neural network-based output prediction attacks on the design of symmetric-key ciphers

   Hayato Watanabe , Ryoma Ito , and Toshihiro Ohigashi

   J. Inf. Secur. Appl., 2025

   DOI Bib

   @article{DBLP:journals/istr/WatanabeIO25,
     author = {Watanabe, Hayato and Ito, Ryoma and Ohigashi, Toshihiro},
     title = {On the effects of neural network-based output prediction attacks on
                       the design of symmetric-key ciphers},
     journal = {J. Inf. Secur. Appl.},
     volume = {90},
     pages = {104016},
     year = {2025},
     url = {https://doi.org/10.1016/j.jisa.2025.104016},
     doi = {10.1016/J.JISA.2025.104016},
     timestamp = {Tue, 01 Apr 2025 19:01:51 +0200},
     biburl = {https://dblp.org/rec/journals/istr/WatanabeIO25.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

4. JISA

   Parallel SAT framework to find clustering of differential characteristics and its applications

   Kosei Sakamoto , Ryoma Ito , and Takanori Isobe

   J. Inf. Secur. Appl., 2025

   DOI Bib

   @article{DBLP:journals/istr/SakamotoII25,
     author = {Sakamoto, Kosei and Ito, Ryoma and Isobe, Takanori},
     title = {Parallel {SAT} framework to find clustering of differential characteristics
                       and its applications},
     journal = {J. Inf. Secur. Appl.},
     volume = {94},
     pages = {104203},
     year = {2025},
     url = {https://doi.org/10.1016/j.jisa.2025.104203},
     doi = {10.1016/J.JISA.2025.104203},
     timestamp = {Sun, 02 Nov 2025 12:35:07 +0100},
     biburl = {https://dblp.org/rec/journals/istr/SakamotoII25.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

5. IACR ToSC

   Divide-and-Conquer SAT for Exploring Optimal Differential and Linear Characteristics and Its Applications

   Kazuma Taka , Kosei Sakamoto , Ryoma Ito , Rentaro Shiba , Shion Utsumi , and Takanori Isobe

   IACR Trans. Symmetric Cryptol., 2025

   DOI Bib Code Slides

   @article{DBLP:journals/tosc/TakaSISUI25,
     author = {Taka, Kazuma and Sakamoto, Kosei and Ito, Ryoma and Shiba, Rentaro and Utsumi, Shion and Isobe, Takanori},
     title = {Divide-and-Conquer {SAT} for Exploring Optimal Differential and Linear
                       Characteristics and Its Applications},
     journal = {{IACR} Trans. Symmetric Cryptol.},
     volume = {2025},
     number = {3},
     pages = {516--576},
     year = {2025},
     url = {https://doi.org/10.46586/tosc.v2025.i3.516-576},
     doi = {10.46586/TOSC.V2025.I3.516-576},
     timestamp = {Sat, 15 Nov 2025 13:54:58 +0100},
     biburl = {https://dblp.org/rec/journals/tosc/TakaSISUI25.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

6. IACR ToSC

   Dialga: A Family of Low-Latency Tweakable Block Ciphers Using Multiple Linear Layers

   Subhadeep Banik , Tatsuya Ishikawa , Takanori Isobe , Ryoma Ito , Kazuhiko Minematsu , Kazuma Nakata , Mostafizar Rahman , and Kosei Sakamoto

   IACR Trans. Symmetric Cryptol., 2025

   DOI Bib Slides

   @article{DBLP:journals/tosc/BanikIIIMNRS25,
     author = {Banik, Subhadeep and Ishikawa, Tatsuya and Isobe, Takanori and Ito, Ryoma and Minematsu, Kazuhiko and Nakata, Kazuma and Rahman, Mostafizar and Sakamoto, Kosei},
     title = {Dialga: {A} Family of Low-Latency Tweakable Block Ciphers Using Multiple
                       Linear Layers},
     journal = {{IACR} Trans. Symmetric Cryptol.},
     volume = {2025},
     number = {4},
     pages = {70--124},
     year = {2025},
     url = {https://doi.org/10.46586/tosc.v2025.i4.70-124},
     doi = {10.46586/TOSC.V2025.I4.70-124},
     timestamp = {Sat, 12 Sep 2026 15:36:30 +0200},
     biburl = {https://dblp.org/rec/journals/tosc/BanikIIIMNRS25.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2023

1. IEICE Trans.

   PNB Based Differential Cryptanalysis of Salsa20 and ChaCha

   Nasratullah Ghafoori , Atsuko Miyaji , Ryoma Ito , and Shotaro Miyashita

   IEICE Trans. Inf. Syst., 2023

   DOI Bib

   @article{DBLP:journals/ieicetd/GhafooriMIM23,
     author = {Ghafoori, Nasratullah and Miyaji, Atsuko and Ito, Ryoma and Miyashita, Shotaro},
     title = {{PNB} Based Differential Cryptanalysis of Salsa20 and ChaCha},
     journal = {{IEICE} Trans. Inf. Syst.},
     volume = {106},
     number = {9},
     pages = {1407--1422},
     year = {2023},
     url = {https://doi.org/10.1587/transinf.2022icp0015},
     doi = {10.1587/TRANSINF.2022ICP0015},
     timestamp = {Sat, 15 Nov 2025 13:52:16 +0100},
     biburl = {https://dblp.org/rec/journals/ieicetd/GhafooriMIM23.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. IPSJ JIP

   Cryptanalysis on End-to-End Encryption Schemes of Communication Tools and Its Research Trend

   Takanori Isobe , Ryoma Ito , and Kazuhiko Minematsu

   J. Inf. Process., 2023

   DOI Bib

   @article{DBLP:journals/jip/IsobeIM23,
     author = {Isobe, Takanori and Ito, Ryoma and Minematsu, Kazuhiko},
     title = {Cryptanalysis on End-to-End Encryption Schemes of Communication Tools
                       and Its Research Trend},
     journal = {J. Inf. Process.},
     volume = {31},
     pages = {523--536},
     year = {2023},
     url = {https://doi.org/10.2197/ipsjjip.31.523},
     doi = {10.2197/IPSJJIP.31.523},
     timestamp = {Sat, 28 Oct 2023 13:59:25 +0200},
     biburl = {https://dblp.org/rec/journals/jip/IsobeIM23.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

3. IPSJ JIP

   A Deeper Look into Deep Learning-based Output Prediction Attacks Using Weak SPN Block Ciphers

   Hayato Kimura , Keita Emura , Takanori Isobe , Ryoma Ito , Kazuto Ogawa , and Toshihiro Ohigashi

   J. Inf. Process., 2023

   DOI Bib

   @article{DBLP:journals/jip/KimuraEIIOO23,
     author = {Kimura, Hayato and Emura, Keita and Isobe, Takanori and Ito, Ryoma and Ogawa, Kazuto and Ohigashi, Toshihiro},
     title = {A Deeper Look into Deep Learning-based Output Prediction Attacks Using
                       Weak {SPN} Block Ciphers},
     journal = {J. Inf. Process.},
     volume = {31},
     pages = {550--561},
     year = {2023},
     url = {https://doi.org/10.2197/ipsjjip.31.550},
     doi = {10.2197/IPSJJIP.31.550},
     timestamp = {Sat, 28 Oct 2023 13:59:25 +0200},
     biburl = {https://dblp.org/rec/journals/jip/KimuraEIIOO23.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

4. IACR TCHES

   Areion: Highly-Efficient Permutations and Its Applications to Hash Functions for Short Input

   Takanori Isobe , Ryoma Ito , Fukang Liu , Kazuhiko Minematsu , Motoki Nakahashi , Kosei Sakamoto , and Rentaro Shiba

   IACR Trans. Cryptogr. Hardw. Embed. Syst., 2023

   DOI Bib Code Slides

   @article{DBLP:journals/tches/IsobeILMNSS23,
     author = {Isobe, Takanori and Ito, Ryoma and Liu, Fukang and Minematsu, Kazuhiko and Nakahashi, Motoki and Sakamoto, Kosei and Shiba, Rentaro},
     title = {Areion: Highly-Efficient Permutations and Its Applications to Hash
                       Functions for Short Input},
     journal = {{IACR} Trans. Cryptogr. Hardw. Embed. Syst.},
     volume = {2023},
     number = {2},
     pages = {115--154},
     year = {2023},
     url = {https://doi.org/10.46586/tches.v2023.i2.115-154},
     doi = {10.46586/TCHES.V2023.I2.115-154},
     timestamp = {Mon, 26 Jun 2023 20:57:37 +0200},
     biburl = {https://dblp.org/rec/journals/tches/IsobeILMNSS23.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

5. IACR ToSC

   Key Committing Security of AEZ and More

   Yu Long Chen , Antonio Flórez-Gutiérrez , Akiko Inoue , Ryoma Ito , Tetsu Iwata , Kazuhiko Minematsu , Nicky Mouha , Yusuke Naito , Ferdinand Sibleyras , and Yosuke Todo

   IACR Trans. Symmetric Cryptol., 2023

   DOI Bib Slides

   @article{DBLP:journals/tosc/ChenFIIIMMNST23,
     author = {Chen, Yu Long and Fl{\'{o}}rez{-}Guti{\'{e}}rrez, Antonio and Inoue, Akiko and Ito, Ryoma and Iwata, Tetsu and Minematsu, Kazuhiko and Mouha, Nicky and Naito, Yusuke and Sibleyras, Ferdinand and Todo, Yosuke},
     title = {Key Committing Security of {AEZ} and More},
     journal = {{IACR} Trans. Symmetric Cryptol.},
     volume = {2023},
     number = {4},
     pages = {452--488},
     year = {2023},
     url = {https://doi.org/10.46586/tosc.v2023.i4.452-488},
     doi = {10.46586/TOSC.V2023.I4.452-488},
     timestamp = {Mon, 05 Feb 2024 20:25:42 +0100},
     biburl = {https://dblp.org/rec/journals/tosc/ChenFIIIMMNST23.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2022

1. IACR ToSC

   Distinguishing and key recovery attacks on the reduced-round SNOW-V and SNOW-Vi

   Jin Hoki , Takanori Isobe , Ryoma Ito , Fukang Liu , and Kosei Sakamoto

   J. Inf. Secur. Appl., 2022

   DOI Bib

   @article{DBLP:journals/istr/HokiIILS22,
     author = {Hoki, Jin and Isobe, Takanori and Ito, Ryoma and Liu, Fukang and Sakamoto, Kosei},
     title = {Distinguishing and key recovery attacks on the reduced-round {SNOW-V}
                       and SNOW-Vi},
     journal = {J. Inf. Secur. Appl.},
     volume = {65},
     pages = {103100},
     year = {2022},
     url = {https://doi.org/10.1016/j.jisa.2021.103100},
     doi = {10.1016/J.JISA.2021.103100},
     timestamp = {Fri, 13 May 2022 19:52:43 +0200},
     biburl = {https://dblp.org/rec/journals/istr/HokiIILS22.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. IACR ToSC

   Cryptanalysis of Rocca and Feasibility of Its Security Claim

   Akinori Hosoyamada , Akiko Inoue , Ryoma Ito , Tetsu Iwata , Kazuhiko Minematsu , Ferdinand Sibleyras , and Yosuke Todo

   IACR Trans. Symmetric Cryptol., 2022

   DOI Bib Code Slides

   @article{DBLP:journals/tosc/HosoyamadaIIIMS22,
     author = {Hosoyamada, Akinori and Inoue, Akiko and Ito, Ryoma and Iwata, Tetsu and Minematsu, Kazuhiko and Sibleyras, Ferdinand and Todo, Yosuke},
     title = {Cryptanalysis of Rocca and Feasibility of Its Security Claim},
     journal = {{IACR} Trans. Symmetric Cryptol.},
     volume = {2022},
     number = {3},
     pages = {123--151},
     year = {2022},
     url = {https://doi.org/10.46586/tosc.v2022.i3.123-151},
     doi = {10.46586/TOSC.V2022.I3.123-151},
     timestamp = {Fri, 05 May 2023 06:50:42 +0200},
     biburl = {https://dblp.org/rec/journals/tosc/HosoyamadaIIIMS22.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

3. IACR ToSC

   New Cryptanalysis of ZUC-256 Initialization Using Modular Differences

   Fukang Liu , Willi Meier , Santanu Sarkar , Gaoli Wang , Ryoma Ito , and Takanori Isobe

   IACR Trans. Symmetric Cryptol., 2022

   DOI Bib Code Slides

   @article{DBLP:journals/tosc/LiuMSWII22,
     author = {Liu, Fukang and Meier, Willi and Sarkar, Santanu and Wang, Gaoli and Ito, Ryoma and Isobe, Takanori},
     title = {New Cryptanalysis of {ZUC-256} Initialization Using Modular Differences},
     journal = {{IACR} Trans. Symmetric Cryptol.},
     volume = {2022},
     number = {3},
     pages = {152--190},
     year = {2022},
     url = {https://doi.org/10.46586/tosc.v2022.i3.152-190},
     doi = {10.46586/TOSC.V2022.I3.152-190},
     timestamp = {Tue, 06 Dec 2022 13:15:32 +0100},
     biburl = {https://dblp.org/rec/journals/tosc/LiuMSWII22.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2021

1. IEEE Access

   Security Analysis of End-to-End Encryption for Zoom Meetings

   Takanori Isobe and Ryoma Ito

   IEEE Access, 2021

   DOI Bib

   @article{DBLP:journals/access/IsobeI21,
     author = {Isobe, Takanori and Ito, Ryoma},
     title = {Security Analysis of End-to-End Encryption for Zoom Meetings},
     journal = {{IEEE} Access},
     volume = {9},
     pages = {90677--90689},
     year = {2021},
     url = {https://doi.org/10.1109/ACCESS.2021.3091722},
     doi = {10.1109/ACCESS.2021.3091722},
     timestamp = {Mon, 28 Aug 2023 21:20:20 +0200},
     biburl = {https://dblp.org/rec/journals/access/IsobeI21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. IEICE Trans.

   New Iterated RC4 Key Correlations and their Application to Plaintext Recovery on WPA-TKIP

   Ryoma Ito and Atsuko Miyaji

   IEICE Trans. Fundam. Electron. Commun. Comput. Sci., 2021

   DOI Bib

   @article{DBLP:journals/ieiceta/ItoM21,
     author = {Ito, Ryoma and Miyaji, Atsuko},
     title = {New Iterated {RC4} Key Correlations and their Application to Plaintext
                       Recovery on {WPA-TKIP}},
     journal = {{IEICE} Trans. Fundam. Electron. Commun. Comput. Sci.},
     volume = {104-A},
     number = {1},
     pages = {190--202},
     year = {2021},
     url = {https://doi.org/10.1587/transfun.2020CIP0006},
     doi = {10.1587/TRANSFUN.2020CIP0006},
     timestamp = {Tue, 07 May 2024 20:20:15 +0200},
     biburl = {https://dblp.org/rec/journals/ieiceta/ItoM21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

3. JISA

   Bit-wise cryptanalysis on AND-RX permutation Friet-PC

   Ryoma Ito , Rentaro Shiba , Kosei Sakamoto , Fukang Liu , and Takanori Isobe

   J. Inf. Secur. Appl., 2021

   DOI Bib

   @article{DBLP:journals/istr/ItoSSLI21,
     author = {Ito, Ryoma and Shiba, Rentaro and Sakamoto, Kosei and Liu, Fukang and Isobe, Takanori},
     title = {Bit-wise cryptanalysis on {AND-RX} permutation Friet-PC},
     journal = {J. Inf. Secur. Appl.},
     volume = {59},
     pages = {102860},
     year = {2021},
     url = {https://doi.org/10.1016/j.jisa.2021.102860},
     doi = {10.1016/J.JISA.2021.102860},
     timestamp = {Sat, 09 Apr 2022 12:25:36 +0200},
     biburl = {https://dblp.org/rec/journals/istr/ItoSSLI21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2017

1. IEICE Trans.

   Refined Construction of RC4 Key Setting in WPA

   Ryoma Ito and Atsuko Miyaji

   IEICE Trans. Fundam. Electron. Commun. Comput. Sci., 2017

   DOI Bib

   @article{DBLP:journals/ieicet/ItoM17,
     author = {Ito, Ryoma and Miyaji, Atsuko},
     title = {Refined Construction of {RC4} Key Setting in {WPA}},
     journal = {{IEICE} Trans. Fundam. Electron. Commun. Comput. Sci.},
     volume = {100-A},
     number = {1},
     pages = {138--148},
     year = {2017},
     url = {https://doi.org/10.1587/transfun.E100.A.138},
     doi = {10.1587/TRANSFUN.E100.A.138},
     timestamp = {Tue, 07 May 2024 20:14:21 +0200},
     biburl = {https://dblp.org/rec/journals/ieicet/ItoM17.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2016

1. IEICE Trans.

   Refined Glimpse Correlations of RC4

   Ryoma Ito and Atsuko Miyaji

   IEICE Trans. Fundam. Electron. Commun. Comput. Sci., 2016

   DOI Bib

   @article{DBLP:journals/ieicet/ItoM16,
     author = {Ito, Ryoma and Miyaji, Atsuko},
     title = {Refined Glimpse Correlations of {RC4}},
     journal = {{IEICE} Trans. Fundam. Electron. Commun. Comput. Sci.},
     volume = {99-A},
     number = {1},
     pages = {3--13},
     year = {2016},
     url = {https://doi.org/10.1587/transfun.E99.A.3},
     doi = {10.1587/TRANSFUN.E99.A.3},
     timestamp = {Tue, 07 May 2024 20:14:21 +0200},
     biburl = {https://dblp.org/rec/journals/ieicet/ItoM16.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. IEICE Trans.

   Refined RC4 Key Correlations of Internal States in WPA

   Ryoma Ito and Atsuko Miyaji

   IEICE Trans. Fundam. Electron. Commun. Comput. Sci., 2016

   DOI Bib

   @article{DBLP:journals/ieicet/ItoM16a,
     author = {Ito, Ryoma and Miyaji, Atsuko},
     title = {Refined {RC4} Key Correlations of Internal States in {WPA}},
     journal = {{IEICE} Trans. Fundam. Electron. Commun. Comput. Sci.},
     volume = {99-A},
     number = {6},
     pages = {1132--1144},
     year = {2016},
     url = {https://doi.org/10.1587/transfun.E99.A.1132},
     doi = {10.1587/TRANSFUN.E99.A.1132},
     timestamp = {Tue, 07 May 2024 20:14:25 +0200},
     biburl = {https://dblp.org/rec/journals/ieicet/ItoM16a.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2026

1. ASIACRYPT

   Finding Collision for HMAC-SHA Forgery in the Secret-State Setting

   Tatsuya Ishikawa , Takanori Isobe , Ryoma Ito , Kosei Sakamoto , Kosuke Sasaki , Kazuma Taka , and Shion Utsumi

   In Advances in Cryptology - ASIACRYPT 2026 - 32th International Conference on the Theory and Application of Cryptology and Information Security (to appear), 2026

   DOI
2. CANS

   Accelerated Differential Search for Gleeok Using Hamming-Weight-Guided SAT Solving

   Kento Morita , Tatsuya Ishikawa , Takuro Shiraya , Kosei Sakamoto , Ryoma Ito , and Takanori Isobe

   In International Conference on Cryptology and Network Security, CANS 2026 (to appear), 2026

   DOI
3. ISITA

   Refining the Evaluation of Diffusion Property for Simon Variants

   Kota Tatsumi , Hayato Watanabe , Ryoma Ito , and Toshihiro Ohigashi

   In International Symposium on Information Theory and Its Applications, ISITA 2026 (to appear), 2026

   DOI
4. ACISP

   Automated Tool for Finding Practical Collisions on SPN-Based Hash Functions

   Keita Toyama , Kosei Sakamoto , Ryoma Ito , Kazuma Taka , Kodai Taiyama , and Takanori Isobe

   In Information Security and Privacy - 31st Australasian Conference, ACISP 2026, Perth, WA, Australia, July 6-9, 2026, Proceedings, Part I, 2026 Acceptance rate: 26.5% (69/260)

   DOI Bib

   @inproceedings{DBLP:conf/acisp/ToyamaSITTI26,
     author = {Toyama, Keita and Sakamoto, Kosei and Ito, Ryoma and Taka, Kazuma and Taiyama, Kodai and Isobe, Takanori},
     editor = {Ma, Siqi and Nepal, Surya},
     title = {Automated Tool for Finding Practical Collisions on SPN-Based Hash
                       Functions},
     booktitle = {Information Security and Privacy - 31st Australasian Conference, {ACISP}
                       2026, Perth, WA, Australia, July 6-9, 2026, Proceedings, Part {I}},
     series = {Lecture Notes in Computer Science},
     volume = {16792},
     pages = {3--39},
     publisher = {Springer},
     year = {2026},
     url = {https://doi.org/10.1007/978-981-92-3012-9\_1},
     doi = {10.1007/978-981-92-3012-9\_1},
     timestamp = {Mon, 03 Aug 2026 20:40:23 +0200},
     biburl = {https://dblp.org/rec/conf/acisp/ToyamaSITTI26.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

5. ACISP

   Analyzing Forgery Security of LeMac: Tight Bounds and Impact of Padding

   Taichi Nagoya , Takuro Shiraya , Kazuma Taka , Tatsuya Ishikawa , Kosei Sakamoto , Ryoma Ito , and Takanori Isobe

   In Information Security and Privacy - 31st Australasian Conference, ACISP 2026, Perth, WA, Australia, July 6-9, 2026, Proceedings, Part I, 2026 Acceptance rate: 26.5% (69/260)

   DOI Bib

   @inproceedings{DBLP:conf/acisp/NagoyaSTISII26,
     author = {Nagoya, Taichi and Shiraya, Takuro and Taka, Kazuma and Ishikawa, Tatsuya and Sakamoto, Kosei and Ito, Ryoma and Isobe, Takanori},
     editor = {Ma, Siqi and Nepal, Surya},
     title = {Analyzing Forgery Security of LeMac: Tight Bounds and Impact of Padding},
     booktitle = {Information Security and Privacy - 31st Australasian Conference, {ACISP}
                       2026, Perth, WA, Australia, July 6-9, 2026, Proceedings, Part {I}},
     series = {Lecture Notes in Computer Science},
     volume = {16792},
     pages = {79--101},
     publisher = {Springer},
     year = {2026},
     url = {https://doi.org/10.1007/978-981-92-3012-9\_4},
     doi = {10.1007/978-981-92-3012-9\_4},
     timestamp = {Mon, 03 Aug 2026 20:40:23 +0200},
     biburl = {https://dblp.org/rec/conf/acisp/NagoyaSTISII26.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2025

1. ACSAC

   Gravity of the Situation: Security Analysis on Rocket.Chat E2EE

   Hayato Kimura , Ryoma Ito , Kazuhiko Minematsu , and Takanori Isobe

   In IEEE Annual Computer Security Applications Conference, ACSAC 2025, Honolulu, HI, USA, December 8-12, 2025, 2025 Acceptance rate: 20.7% (84/406)

   DOI Bib Code Slides Website

   @inproceedings{DBLP:conf/acsac/KimuraIMI25,
     author = {Kimura, Hayato and Ito, Ryoma and Minematsu, Kazuhiko and Isobe, Takanori},
     title = {Gravity of the Situation: Security Analysis on Rocket.Chat {E2EE}},
     booktitle = {{IEEE} Annual Computer Security Applications Conference, {ACSAC} 2025,
                       Honolulu, HI, USA, December 8-12, 2025},
     pages = {15--30},
     publisher = {{IEEE}},
     year = {2025},
     url = {https://doi.org/10.1109/ACSAC67867.2025.00018},
     doi = {10.1109/ACSAC67867.2025.00018},
     timestamp = {Sun, 21 Jun 2026 17:17:38 +0200},
     biburl = {https://dblp.org/rec/conf/acsac/KimuraIMI25.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. EuroS&P

   Not in The Prophecies: Practical Attacks on Nostr

   Hayato Kimura , Ryoma Ito , Kazuhiko Minematsu , Shogo Shiraki , and Takanori Isobe

   In 10th IEEE European Symposium on Security and Privacy, EuroS&P 2025, Venice, Italy, June 30 - July 4, 2025, 2025 Acceptance rate: 21.9% (60/273)

   DOI Bib Code Website

   @inproceedings{DBLP:conf/eurosp/KimuraIMSI25,
     author = {Kimura, Hayato and Ito, Ryoma and Minematsu, Kazuhiko and Shiraki, Shogo and Isobe, Takanori},
     title = {Not in The Prophecies: Practical Attacks on Nostr},
     booktitle = {10th {IEEE} European Symposium on Security and Privacy, EuroS{\&}P
                       2025, Venice, Italy, June 30 - July 4, 2025},
     pages = {585--606},
     publisher = {{IEEE}},
     year = {2025},
     url = {https://doi.org/10.1109/EuroSP63326.2025.00040},
     doi = {10.1109/EUROSP63326.2025.00040},
     timestamp = {Tue, 14 Oct 2025 19:35:20 +0200},
     biburl = {https://dblp.org/rec/conf/eurosp/KimuraIMSI25.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

3. ICISC

   Comprehensive Security Analysis of End-to-End Encryption in LINE

   Takehiro Matsumoto , Atsushi Tanaka , Kyosuke Yamashita , Ryoma Ito , and Takanori Isobe

   In Information Security and Cryptology - ICISC 2025 - 28th International Conference, Seoul, South Korea, November 19-21, 2025, Revised Selected Papers, 2025 Acceptance rate: 37.8% (28/74)

   DOI Bib

   @inproceedings{DBLP:conf/icisc/MatsumotoTYII25,
     author = {Matsumoto, Takehiro and Tanaka, Atsushi and Yamashita, Kyosuke and Ito, Ryoma and Isobe, Takanori},
     editor = {Seo, Hwajeong},
     title = {Comprehensive Security Analysis of End-to-End Encryption in {LINE}},
     booktitle = {Information Security and Cryptology - {ICISC} 2025 - 28th International
                       Conference, Seoul, South Korea, November 19-21, 2025, Revised Selected
                       Papers},
     series = {Lecture Notes in Computer Science},
     volume = {16487},
     pages = {237--256},
     publisher = {Springer},
     year = {2025},
     url = {https://doi.org/10.1007/978-981-95-8034-7\_13},
     doi = {10.1007/978-981-95-8034-7\_13},
     timestamp = {Sun, 21 Jun 2026 17:19:16 +0200},
     biburl = {https://dblp.org/rec/conf/icisc/MatsumotoTYII25.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2024

1. ASIACRYPT

   Key Collisions on AES and Its Applications

   Kodai Taiyama , Kosei Sakamoto , Ryoma Ito , Kazuma Taka , and Takanori Isobe

   In Advances in Cryptology - ASIACRYPT 2024 - 30th International Conference on the Theory and Application of Cryptology and Information Security, Kolkata, India, December 9-13, 2024, Proceedings, Part VII, 2024 Acceptance rate: 29.2% (127/435)

   DOI Bib Slides

   @inproceedings{DBLP:conf/asiacrypt/TaiyamaSITI24,
     author = {Taiyama, Kodai and Sakamoto, Kosei and Ito, Ryoma and Taka, Kazuma and Isobe, Takanori},
     editor = {Chung, Kai{-}Min and Sasaki, Yu},
     title = {Key Collisions on {AES} and Its Applications},
     booktitle = {Advances in Cryptology - {ASIACRYPT} 2024 - 30th International Conference
                       on the Theory and Application of Cryptology and Information Security,
                       Kolkata, India, December 9-13, 2024, Proceedings, Part {VII}},
     series = {Lecture Notes in Computer Science},
     volume = {15490},
     pages = {267--300},
     publisher = {Springer},
     year = {2024},
     url = {https://doi.org/10.1007/978-981-96-0941-3\_9},
     doi = {10.1007/978-981-96-0941-3\_9},
     timestamp = {Tue, 21 Apr 2026 08:16:24 +0200},
     biburl = {https://dblp.org/rec/conf/asiacrypt/TaiyamaSITI24.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. CSCML

   On the Effects of Neural Network-Based Output Prediction Attacks on the Design of Symmetric-Key Ciphers

   Hayato Watanabe , Ryoma Ito , and Toshihiro Ohigashi

   In Cyber Security, Cryptology, and Machine Learning - 8th International Symposium, CSCML 2024, Be’er Sheva, Israel, December 19-20, 2024, Proceedings, 2024 Acceptance rate: 37.2% (16/43)

   DOI Bib Slides

   @inproceedings{DBLP:conf/cscml/WatanabeIO24,
     author = {Watanabe, Hayato and Ito, Ryoma and Ohigashi, Toshihiro},
     editor = {Dolev, Shlomi and Elhadad, Michael and Kutylowski, Miroslaw and Persiano, Giuseppe},
     title = {On the Effects of Neural Network-Based Output Prediction Attacks on
                       the Design of Symmetric-Key Ciphers},
     booktitle = {Cyber Security, Cryptology, and Machine Learning - 8th International
                       Symposium, {CSCML} 2024, Be'er Sheva, Israel, December 19-20, 2024,
                       Proceedings},
     series = {Lecture Notes in Computer Science},
     volume = {15349},
     pages = {201--218},
     publisher = {Springer},
     year = {2024},
     url = {https://doi.org/10.1007/978-3-031-76934-4\_13},
     doi = {10.1007/978-3-031-76934-4\_13},
     timestamp = {Sat, 25 Jan 2025 23:07:01 +0100},
     biburl = {https://dblp.org/rec/conf/cscml/WatanabeIO24.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2023

1. SAC

   Parallel SAT Framework to Find Clustering of Differential Characteristics and Its Applications

   Kosei Sakamoto , Ryoma Ito , and Takanori Isobe

   In Selected Areas in Cryptography - SAC 2023 - 30th International Conference, Fredericton, Canada, August 14-18, 2023, Revised Selected Papers, 2023 Acceptance rate: 43.7% (21/48)

   DOI Bib Slides

   @inproceedings{DBLP:conf/sacrypt/Sakamoto0023,
     author = {Sakamoto, Kosei and Ito, Ryoma and Isobe, Takanori},
     editor = {Carlet, Claude and Mandal, Kalikinkar and Rijmen, Vincent},
     title = {Parallel {SAT} Framework to Find Clustering of Differential Characteristics
                       and Its Applications},
     booktitle = {Selected Areas in Cryptography - {SAC} 2023 - 30th International Conference,
                       Fredericton, Canada, August 14-18, 2023, Revised Selected Papers},
     series = {Lecture Notes in Computer Science},
     volume = {14201},
     pages = {409--428},
     publisher = {Springer},
     year = {2023},
     url = {https://doi.org/10.1007/978-3-031-53368-6\_20},
     doi = {10.1007/978-3-031-53368-6\_20},
     timestamp = {Tue, 07 May 2024 20:12:23 +0200},
     biburl = {https://dblp.org/rec/conf/sacrypt/Sakamoto0023.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2022

1. ACISP

   PNB-Focused Differential Cryptanalysis of ChaCha Stream Cipher

   Shotaro Miyashita , Ryoma Ito , and Atsuko Miyaji

   In Information Security and Privacy - 27th Australasian Conference, ACISP 2022, Wollongong, NSW, Australia, November 28-30, 2022, Proceedings, 2022 Acceptance rate: 40.3% (25/62)

   DOI Bib

   @inproceedings{DBLP:conf/acisp/MiyashitaIM22,
     author = {Miyashita, Shotaro and Ito, Ryoma and Miyaji, Atsuko},
     editor = {Nguyen, Khoa and Yang, Guomin and Guo, Fuchun and Susilo, Willy},
     title = {PNB-Focused Differential Cryptanalysis of ChaCha Stream Cipher},
     booktitle = {Information Security and Privacy - 27th Australasian Conference, {ACISP}
                       2022, Wollongong, NSW, Australia, November 28-30, 2022, Proceedings},
     series = {Lecture Notes in Computer Science},
     volume = {13494},
     pages = {46--66},
     publisher = {Springer},
     year = {2022},
     url = {https://doi.org/10.1007/978-3-031-22301-3\_3},
     doi = {10.1007/978-3-031-22301-3\_3},
     timestamp = {Tue, 07 May 2024 20:09:57 +0200},
     biburl = {https://dblp.org/rec/conf/acisp/MiyashitaIM22.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. AIoTS

   Output Prediction Attacks on Block Ciphers Using Deep Learning

   Hayato Kimura , Keita Emura , Takanori Isobe , Ryoma Ito , Kazuto Ogawa , and Toshihiro Ohigashi

   In Applied Cryptography and Network Security Workshops - ACNS 2022 Satellite Workshops, AIBlock, AIHWS, AIoTS, CIMSS, Cloud S&P, SCI, SecMT, SiMLA, Rome, Italy, June 20-23, 2022, Proceedings, 2022 Acceptance rate: 59.6% (31/52)

   DOI Bib

   @inproceedings{DBLP:conf/acns/KimuraEIIOO22,
     author = {Kimura, Hayato and Emura, Keita and Isobe, Takanori and Ito, Ryoma and Ogawa, Kazuto and Ohigashi, Toshihiro},
     editor = {Zhou, Jianying and Adepu, Sridhar and Alcaraz, Cristina and Batina, Lejla and Casalicchio, Emiliano and Chattopadhyay, Sudipta and Jin, Chenglu and Lin, Jingqiang and Losiouk, Eleonora and Majumdar, Suryadipta and Meng, Weizhi and Picek, Stjepan and Shao, Jun and Su, Chunhua and Wang, Cong and Zhauniarovich, Yury and Zonouz, Saman A.},
     title = {Output Prediction Attacks on Block Ciphers Using Deep Learning},
     booktitle = {Applied Cryptography and Network Security Workshops - {ACNS} 2022
                       Satellite Workshops, AIBlock, AIHWS, AIoTS, CIMSS, Cloud S{\&}P,
                       SCI, SecMT, SiMLA, Rome, Italy, June 20-23, 2022, Proceedings},
     series = {Lecture Notes in Computer Science},
     volume = {13285},
     pages = {248--276},
     publisher = {Springer},
     year = {2022},
     url = {https://doi.org/10.1007/978-3-031-16815-4\_15},
     doi = {10.1007/978-3-031-16815-4\_15},
     timestamp = {Thu, 06 Feb 2025 08:19:07 +0100},
     biburl = {https://dblp.org/rec/conf/acns/KimuraEIIOO22.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

3. ICEIS

   State-free End-to-End Encrypted Storage and Chat Systems based on Searchable Encryption

   Keita Emura , Ryoma Ito , Sachiko Kanamori , Ryo Nojima , and Yohei Watanabe

   In Proceedings of the 24th International Conference on Enterprise Information Systems, ICEIS 2022, Online Streaming, April 25-27, 2022, Volume 2, 2022 Acceptance rate: 32.0% (63/197)

   DOI Bib

   @inproceedings{DBLP:conf/iceis/Emura0KN022,
     author = {Emura, Keita and Ito, Ryoma and Kanamori, Sachiko and Nojima, Ryo and Watanabe, Yohei},
     editor = {Filipe, Joaquim and Smialek, Michal and Brodsky, Alexander and Hammoudi, Slimane},
     title = {State-free End-to-End Encrypted Storage and Chat Systems based on
                       Searchable Encryption},
     booktitle = {Proceedings of the 24th International Conference on Enterprise Information
                       Systems, {ICEIS} 2022, Online Streaming, April 25-27, 2022, Volume
                       2},
     pages = {106--113},
     publisher = {{SCITEPRESS}},
     year = {2022},
     url = {https://doi.org/10.5220/0011045200003179},
     doi = {10.5220/0011045200003179},
     timestamp = {Tue, 06 Jun 2023 14:58:01 +0200},
     biburl = {https://dblp.org/rec/conf/iceis/Emura0KN022.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2021

1. ACISP

   Distinguishing and Key Recovery Attacks on the Reduced-Round SNOW-V

   Jin Hoki , Takanori Isobe , Ryoma Ito , Fukang Liu , and Kosei Sakamoto

   In Information Security and Privacy - 26th Australasian Conference, ACISP 2021, Virtual Event, December 1-3, 2021, Proceedings, 2021 Acceptance rate: 22.2% (35/157)

   DOI Bib Slides

   @inproceedings{DBLP:conf/acisp/HokiIILS21,
     author = {Hoki, Jin and Isobe, Takanori and Ito, Ryoma and Liu, Fukang and Sakamoto, Kosei},
     editor = {Baek, Joonsang and Ruj, Sushmita},
     title = {Distinguishing and Key Recovery Attacks on the Reduced-Round {SNOW-V}},
     booktitle = {Information Security and Privacy - 26th Australasian Conference, {ACISP}
                       2021, Virtual Event, December 1-3, 2021, Proceedings},
     series = {Lecture Notes in Computer Science},
     volume = {13083},
     pages = {171--190},
     publisher = {Springer},
     year = {2021},
     url = {https://doi.org/10.1007/978-3-030-90567-5\_9},
     doi = {10.1007/978-3-030-90567-5\_9},
     timestamp = {Mon, 03 Jan 2022 22:39:44 +0100},
     biburl = {https://dblp.org/rec/conf/acisp/HokiIILS21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. ACISP

   Security Analysis of End-to-End Encryption for Zoom Meetings

   Takanori Isobe and Ryoma Ito

   In Information Security and Privacy - 26th Australasian Conference, ACISP 2021, Virtual Event, December 1-3, 2021, Proceedings, 2021 Acceptance rate: 22.2% (35/157)

   DOI Bib Slides

   @inproceedings{DBLP:conf/acisp/IsobeI21,
     author = {Isobe, Takanori and Ito, Ryoma},
     editor = {Baek, Joonsang and Ruj, Sushmita},
     title = {Security Analysis of End-to-End Encryption for Zoom Meetings},
     booktitle = {Information Security and Privacy - 26th Australasian Conference, {ACISP}
                       2021, Virtual Event, December 1-3, 2021, Proceedings},
     series = {Lecture Notes in Computer Science},
     volume = {13083},
     pages = {234--253},
     publisher = {Springer},
     year = {2021},
     url = {https://doi.org/10.1007/978-3-030-90567-5\_12},
     doi = {10.1007/978-3-030-90567-5\_12},
     timestamp = {Mon, 03 Jan 2022 22:39:43 +0100},
     biburl = {https://dblp.org/rec/conf/acisp/IsobeI21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

3. ESORICS

   Security Analysis of SFrame

   Takanori Isobe , Ryoma Ito , and Kazuhiko Minematsu

   In Computer Security - ESORICS 2021 - 26th European Symposium on Research in Computer Security, Darmstadt, Germany, October 4-8, 2021, Proceedings, Part II, 2021 Acceptance rate: 20.2% (71/351)

   DOI Bib Slides

   @inproceedings{DBLP:conf/esorics/IsobeIM21,
     author = {Isobe, Takanori and Ito, Ryoma and Minematsu, Kazuhiko},
     editor = {Bertino, Elisa and Schulmann, Haya and Waidner, Michael},
     title = {Security Analysis of SFrame},
     booktitle = {Computer Security - {ESORICS} 2021 - 26th European Symposium on Research
                       in Computer Security, Darmstadt, Germany, October 4-8, 2021, Proceedings,
                       Part {II}},
     series = {Lecture Notes in Computer Science},
     volume = {12973},
     pages = {127--146},
     publisher = {Springer},
     year = {2021},
     url = {https://doi.org/10.1007/978-3-030-88428-4\_7},
     doi = {10.1007/978-3-030-88428-4\_7},
     timestamp = {Tue, 17 Oct 2023 10:41:56 +0200},
     biburl = {https://dblp.org/rec/conf/esorics/IsobeIM21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2020

1. ISC

   Rotational Cryptanalysis of Salsa Core Function

   Ryoma Ito

   In Information Security - 23rd International Conference, ISC 2020, Bali, Indonesia, December 16-18, 2020, Proceedings, 2020 Acceptance rate: 26.4% (23/87)

   DOI Bib Slides

   @inproceedings{DBLP:conf/isw/Ito20,
     author = {Ito, Ryoma},
     editor = {Susilo, Willy and Deng, Robert H. and Guo, Fuchun and Li, Yannan and Intan, Rolly},
     title = {Rotational Cryptanalysis of Salsa Core Function},
     booktitle = {Information Security - 23rd International Conference, {ISC} 2020,
                       Bali, Indonesia, December 16-18, 2020, Proceedings},
     series = {Lecture Notes in Computer Science},
     volume = {12472},
     pages = {129--145},
     publisher = {Springer},
     year = {2020},
     url = {https://doi.org/10.1007/978-3-030-62974-8\_8},
     doi = {10.1007/978-3-030-62974-8\_8},
     timestamp = {Tue, 10 Feb 2026 15:42:19 +0100},
     biburl = {https://dblp.org/rec/conf/isw/Ito20.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2018

1. ACISP

   New Iterated RC4 Key Correlations

   Ryoma Ito and Atsuko Miyaji

   In Information Security and Privacy - 23rd Australasian Conference, ACISP 2018, Wollongong, NSW, Australia, July 11-13, 2018, Proceedings, 2018 Acceptance rate: 30.1% (41/136)

   DOI Bib Slides

   @inproceedings{DBLP:conf/acisp/ItoM18,
     author = {Ito, Ryoma and Miyaji, Atsuko},
     editor = {Susilo, Willy and Yang, Guomin},
     title = {New Iterated {RC4} Key Correlations},
     booktitle = {Information Security and Privacy - 23rd Australasian Conference, {ACISP}
                       2018, Wollongong, NSW, Australia, July 11-13, 2018, Proceedings},
     series = {Lecture Notes in Computer Science},
     volume = {10946},
     pages = {154--171},
     publisher = {Springer},
     year = {2018},
     url = {https://doi.org/10.1007/978-3-319-93638-3\_10},
     doi = {10.1007/978-3-319-93638-3\_10},
     timestamp = {Tue, 07 May 2024 20:09:57 +0200},
     biburl = {https://dblp.org/rec/conf/acisp/ItoM18.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2015

1. ACISP

   How TKIP Induces Biases of Internal States of Generic RC4

   Ryoma Ito and Atsuko Miyaji

   In Information Security and Privacy - 20th Australasian Conference, ACISP 2015, Brisbane, QLD, Australia, June 29 - July 1, 2015, Proceedings, 2015 Acceptance rate: 25.0% (28/112)

   DOI Bib Slides

   @inproceedings{DBLP:conf/acisp/ItoM15,
     author = {Ito, Ryoma and Miyaji, Atsuko},
     editor = {Foo, Ernest and Stebila, Douglas},
     title = {How {TKIP} Induces Biases of Internal States of Generic {RC4}},
     booktitle = {Information Security and Privacy - 20th Australasian Conference, {ACISP}
                       2015, Brisbane, QLD, Australia, June 29 - July 1, 2015, Proceedings},
     series = {Lecture Notes in Computer Science},
     volume = {9144},
     pages = {329--342},
     publisher = {Springer},
     year = {2015},
     url = {https://doi.org/10.1007/978-3-319-19962-7\_19},
     doi = {10.1007/978-3-319-19962-7\_19},
     timestamp = {Tue, 07 May 2024 20:09:57 +0200},
     biburl = {https://dblp.org/rec/conf/acisp/ItoM15.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. FSE

   New Linear Correlations Related to State Information of RC4 PRGA Using IV in WPA

   Ryoma Ito and Atsuko Miyaji

   In Fast Software Encryption - 22nd International Workshop, FSE 2015, Istanbul, Turkey, March 8-11, 2015, Revised Selected Papers, 2015 Acceptance rate: 39.4% (28/71)

   DOI Bib Slides

   @inproceedings{DBLP:conf/fse/ItoM15,
     author = {Ito, Ryoma and Miyaji, Atsuko},
     editor = {Leander, Gregor},
     title = {New Linear Correlations Related to State Information of {RC4} {PRGA}
                       Using {IV} in {WPA}},
     booktitle = {Fast Software Encryption - 22nd International Workshop, {FSE} 2015,
                       Istanbul, Turkey, March 8-11, 2015, Revised Selected Papers},
     series = {Lecture Notes in Computer Science},
     volume = {9054},
     pages = {557--576},
     publisher = {Springer},
     year = {2015},
     url = {https://doi.org/10.1007/978-3-662-48116-5\_27},
     doi = {10.1007/978-3-662-48116-5\_27},
     timestamp = {Tue, 07 May 2024 20:11:45 +0200},
     biburl = {https://dblp.org/rec/conf/fse/ItoM15.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2014

1. WISA

   New Integrated Long-Term Glimpse of RC4

   Ryoma Ito and Atsuko Miyaji

   In Information Security Applications - 15th International Workshop, WISA 2014, Jeju Island, Korea, August 25-27, 2014. Revised Selected Papers, 2014 Acceptance rate: 44.9% (31/69)

   DOI Bib Slides

   @inproceedings{DBLP:conf/wisa/ItoM14,
     author = {Ito, Ryoma and Miyaji, Atsuko},
     editor = {Rhee, Kyung Hyune and Yi, Jeong Hyun},
     title = {New Integrated Long-Term Glimpse of {RC4}},
     booktitle = {Information Security Applications - 15th International Workshop, {WISA}
                       2014, Jeju Island, Korea, August 25-27, 2014. Revised Selected Papers},
     series = {Lecture Notes in Computer Science},
     volume = {8909},
     pages = {137--149},
     publisher = {Springer},
     year = {2014},
     url = {https://doi.org/10.1007/978-3-319-15087-1\_11},
     doi = {10.1007/978-3-319-15087-1\_11},
     timestamp = {Tue, 07 May 2024 20:08:19 +0200},
     biburl = {https://dblp.org/rec/conf/wisa/ItoM14.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2026

1. ePrint

   Dialga: A Family of Low-Latency Tweakable Block Ciphers using Multiple Linear Layers (Full Version)

   Subhadeep Banik , Tatsuya Ishikawa , Takanori Isobe , Ryoma Ito , Kazuhiko Minematsu , Kazuma Nakata , Mostafizar Rahman , and Kosei Sakamoto

   IACR Cryptol. ePrint Arch., 2026

   Bib

   @article{DBLP:journals/iacr/BanikIIIMNRS26,
     author = {Banik, Subhadeep and Ishikawa, Tatsuya and Isobe, Takanori and Ito, Ryoma and Minematsu, Kazuhiko and Nakata, Kazuma and Rahman, Mostafizar and Sakamoto, Kosei},
     title = {Dialga: {A} Family of Low-Latency Tweakable Block Ciphers using Multiple
                       Linear Layers (Full Version)},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2026},
     pages = {547},
     year = {2026},
     url = {https://eprint.iacr.org/2026/547},
     timestamp = {Wed, 12 Aug 2026 11:49:08 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/BanikIIIMNRS26.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2025

1. ePrint

   Not in The Prophecies: Practical Attacks on Nostr

   Hayato Kimura , Ryoma Ito , Kazuhiko Minematsu , Shogo Shiraki , and Takanori Isobe

   IACR Cryptol. ePrint Arch., 2025

   Bib Code Website

   @article{DBLP:journals/iacr/KimuraIMSI25,
     author = {Kimura, Hayato and Ito, Ryoma and Minematsu, Kazuhiko and Shiraki, Shogo and Isobe, Takanori},
     title = {Not in The Prophecies: Practical Attacks on Nostr},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2025},
     pages = {1459},
     year = {2025},
     url = {https://eprint.iacr.org/2025/1459},
     timestamp = {Thu, 28 Aug 2025 17:00:42 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/KimuraIMSI25.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. ePrint

   Gravity of the Situation:Security Analysis on Rocket.Chat E2EE

   Hayato Kimura , Ryoma Ito , Kazuhiko Minematsu , and Takanori Isobe

   IACR Cryptol. ePrint Arch., 2025

   Bib Code Website

   @article{DBLP:journals/iacr/KimuraIMI25,
     author = {Kimura, Hayato and Ito, Ryoma and Minematsu, Kazuhiko and Isobe, Takanori},
     title = {Gravity of the Situation:Security Analysis on Rocket.Chat {E2EE}},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2025},
     pages = {2300},
     year = {2025},
     url = {https://eprint.iacr.org/2025/2300},
     timestamp = {Tue, 13 Jan 2026 11:09:23 +0100},
     biburl = {https://dblp.org/rec/journals/iacr/KimuraIMI25.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2024

1. ePrint

   On the Effects of Neural Network-based Output Prediction Attacks on the Design of Symmetric-key Ciphers

   Hayato Watanabe , Ryoma Ito , and Toshihiro Ohigashi

   IACR Cryptol. ePrint Arch., 2024

   Bib

   @article{DBLP:journals/iacr/WatanabeIO24,
     author = {Watanabe, Hayato and Ito, Ryoma and Ohigashi, Toshihiro},
     title = {On the Effects of Neural Network-based Output Prediction Attacks on
                       the Design of Symmetric-key Ciphers},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2024},
     pages = {1310},
     year = {2024},
     url = {https://eprint.iacr.org/2024/1310},
     timestamp = {Sun, 01 Sep 2024 21:15:38 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/WatanabeIO24.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. ePrint

   Key Collisions on AES and Its Applications

   Kodai Taiyama , Kosei Sakamoto , Ryoma Ito , Kazuma Taka , and Takanori Isobe

   IACR Cryptol. ePrint Arch., 2024

   Bib

   @article{DBLP:journals/iacr/TaiyamaSITI24,
     author = {Taiyama, Kodai and Sakamoto, Kosei and Ito, Ryoma and Taka, Kazuma and Isobe, Takanori},
     title = {Key Collisions on {AES} and Its Applications},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2024},
     pages = {1508},
     year = {2024},
     url = {https://eprint.iacr.org/2024/1508},
     timestamp = {Sat, 05 Oct 2024 20:55:34 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/TaiyamaSITI24.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2023

1. ePrint

   Areion: Highly-Efficient Permutations and Its Applications (Extended Version)

   Takanori Isobe , Ryoma Ito , Fukang Liu , Kazuhiko Minematsu , Motoki Nakahashi , Kosei Sakamoto , and Rentaro Shiba

   IACR Cryptol. ePrint Arch., 2023

   Bib Code

   @article{DBLP:journals/iacr/IsobeILMNSS23,
     author = {Isobe, Takanori and Ito, Ryoma and Liu, Fukang and Minematsu, Kazuhiko and Nakahashi, Motoki and Sakamoto, Kosei and Shiba, Rentaro},
     title = {Areion: Highly-Efficient Permutations and Its Applications (Extended
                       Version)},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2023},
     pages = {794},
     year = {2023},
     url = {https://eprint.iacr.org/2023/794},
     timestamp = {Mon, 03 Jul 2023 20:30:02 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/IsobeILMNSS23.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. ePrint

   Parallel SAT Framework to Find Clustering of Differential Characteristics and Its Applications

   Kosei Sakamoto , Ryoma Ito , and Takanori Isobe

   IACR Cryptol. ePrint Arch., 2023

   Bib

   @article{DBLP:journals/iacr/SakamotoII23,
     author = {Sakamoto, Kosei and Ito, Ryoma and Isobe, Takanori},
     title = {Parallel {SAT} Framework to Find Clustering of Differential Characteristics
                       and Its Applications},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2023},
     pages = {1227},
     year = {2023},
     url = {https://eprint.iacr.org/2023/1227},
     timestamp = {Fri, 08 Sep 2023 15:28:09 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/SakamotoII23.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2021

1. ePrint

   Bit-wise Cryptanalysis on AND-RX Permutation Friet-PC

   Ryoma Ito , Rentaro Shiba , Kosei Sakamoto , Fukang Liu , and Takanori Isobe

   IACR Cryptol. ePrint Arch., 2021

   Bib

   @article{DBLP:journals/iacr/ItoSSL021,
     author = {Ito, Ryoma and Shiba, Rentaro and Sakamoto, Kosei and Liu, Fukang and Isobe, Takanori},
     title = {Bit-wise Cryptanalysis on {AND-RX} Permutation Friet-PC},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2021},
     pages = {212},
     year = {2021},
     url = {https://eprint.iacr.org/2021/212},
     timestamp = {Mon, 26 Jul 2021 08:20:04 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/ItoSSL021.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

2. ePrint

   Output Prediction Attacks on SPN Block Ciphers using Deep Learning

   Hayato Kimura , Keita Emura , Takanori Isobe , Ryoma Ito , Kazuto Ogawa , and Toshihiro Ohigashi

   IACR Cryptol. ePrint Arch., 2021

   Bib

   @article{DBLP:journals/iacr/0002E0IOO21,
     author = {Kimura, Hayato and Emura, Keita and Isobe, Takanori and Ito, Ryoma and Ogawa, Kazuto and Ohigashi, Toshihiro},
     title = {Output Prediction Attacks on {SPN} Block Ciphers using Deep Learning},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2021},
     pages = {401},
     year = {2021},
     url = {https://eprint.iacr.org/2021/401},
     timestamp = {Mon, 26 Jul 2021 08:20:06 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/0002E0IOO21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

3. ePrint

   Security Analysis of SFrame

   Takanori Isobe , Ryoma Ito , and Kazuhiko Minematsu

   IACR Cryptol. ePrint Arch., 2021

   Bib

   @article{DBLP:journals/iacr/IsobeIM21,
     author = {Isobe, Takanori and Ito, Ryoma and Minematsu, Kazuhiko},
     title = {Security Analysis of SFrame},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2021},
     pages = {424},
     year = {2021},
     url = {https://eprint.iacr.org/2021/424},
     timestamp = {Mon, 26 Jul 2021 08:20:08 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/IsobeIM21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

4. ePrint

   Security Analysis of End-to-End Encryption for Zoom Meetings

   Takanori Isobe and Ryoma Ito

   IACR Cryptol. ePrint Arch., 2021

   Bib

   @article{DBLP:journals/iacr/IsobeI21,
     author = {Isobe, Takanori and Ito, Ryoma},
     title = {Security Analysis of End-to-End Encryption for Zoom Meetings},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2021},
     pages = {486},
     year = {2021},
     url = {https://eprint.iacr.org/2021/486},
     timestamp = {Mon, 26 Jul 2021 08:20:10 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/IsobeI21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

5. ePrint

   Distinguishing and Key Recovery Attacks on the Reduced-Round SNOW-V

   Jin Hoki , Takanori Isobe , Ryoma Ito , Fukang Liu , and Kosei Sakamoto

   IACR Cryptol. ePrint Arch., 2021

   Bib

   @article{DBLP:journals/iacr/HokiIILS21,
     author = {Hoki, Jin and Isobe, Takanori and Ito, Ryoma and Liu, Fukang and Sakamoto, Kosei},
     title = {Distinguishing and Key Recovery Attacks on the Reduced-Round {SNOW-V}},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2021},
     pages = {546},
     year = {2021},
     url = {https://eprint.iacr.org/2021/546},
     timestamp = {Mon, 26 Jul 2021 08:20:12 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/HokiIILS21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

6. ePrint

   State-free End-to-End Encrypted Storage and Chat Systems based on Searchable Encryption

   Keita Emura , Ryoma Ito , Sachiko Kanamori , Ryo Nojima , and Yohei Watanabe

   IACR Cryptol. ePrint Arch., 2021

   Bib

   @article{DBLP:journals/iacr/EmuraIKNW21,
     author = {Emura, Keita and Ito, Ryoma and Kanamori, Sachiko and Nojima, Ryo and Watanabe, Yohei},
     title = {State-free End-to-End Encrypted Storage and Chat Systems based on
                       Searchable Encryption},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2021},
     pages = {953},
     year = {2021},
     url = {https://eprint.iacr.org/2021/953},
     timestamp = {Mon, 09 Aug 2021 16:25:39 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/EmuraIKNW21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

7. ePrint

   Finding Practical Distinguishers for ZUC-256 Using Modular Differences

   Fukang Liu , Willi Meier , Santanu Sarkar , Gaoli Wang , Ryoma Ito , and Takanori Isobe

   IACR Cryptol. ePrint Arch., 2021

   Bib

   @article{DBLP:journals/iacr/LiuM0W0021,
     author = {Liu, Fukang and Meier, Willi and Sarkar, Santanu and Wang, Gaoli and Ito, Ryoma and Isobe, Takanori},
     title = {Finding Practical Distinguishers for {ZUC-256} Using Modular Differences},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2021},
     pages = {1104},
     year = {2021},
     url = {https://eprint.iacr.org/2021/1104},
     timestamp = {Mon, 06 Sep 2021 18:25:17 +0200},
     biburl = {https://dblp.org/rec/journals/iacr/LiuM0W0021.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }

8. ePrint

   PNB-based Differential Cryptanalysis of ChaCha Stream Cipher

   Shotaro Miyashita , Ryoma Ito , and Atsuko Miyaji

   IACR Cryptol. ePrint Arch., 2021

   Bib

   @article{DBLP:journals/iacr/MiyashitaIM21,
     author = {Miyashita, Shotaro and Ito, Ryoma and Miyaji, Atsuko},
     title = {PNB-based Differential Cryptanalysis of ChaCha Stream Cipher},
     journal = {{IACR} Cryptol. ePrint Arch.},
     volume = {2021},
     pages = {1537},
     year = {2021},
     url = {https://eprint.iacr.org/2021/1537},
     timestamp = {Fri, 10 Dec 2021 18:59:30 +0100},
     biburl = {https://dblp.org/rec/journals/iacr/MiyashitaIM21.bib},
     bibsource = {dblp computer science bibliography, https://dblp.org}
   }