Table of Contents

Curriculum Vitae

An overview of my professional experience, education, selected publications and talks, awards, academic service, and teaching.

Contact Information

Name Ryoma Ito
Professional Title Planning Manager
Research Manager
Email itorym [at] nict.go.jp
Website https://itorym.github.io/

Professional Experience

  • 2026–Present

    Japan

    Planning Manager
    National Institute of Information and Communications TechnologyStrategic Planning Office, Strategic Planning Department
  • 2026–Present

    Japan

    Research Manager
    National Institute of Information and Communications TechnologySecurity Fundamentals Laboratory, Cybersecurity Research Institute
  • 2025–Present

    Japan

    Guest Associate Professor
    The University of OsakaGraduate School of Information Science and Technology
  • 2025–Present

    Japan

    Part-time Lecturer
    Toho UniversityDepartment of Information Science, Faculty of Science
  • 2020–2026

    Japan

    Research Manager
    National Institute of Information and Communications TechnologySecurity Fundamentals Laboratory, Cybersecurity Research Institute
  • 2009–2020

    Japan

    Information and Communications Officer
    Ministry of DefenseJapan Air Self-Defense Force

Education

  • 2017–2019

    Japan

    Ph.D. in Engineering
    The University of Osaka
  • 2013–2015

    Japan

    Master’s degree in Information Science
    Japan Advanced Institute of Science and Technology
    • Supervisor: Prof. Atsuko Miyaji
  • 2005–2009

    Japan

    Bachelor’s degree in Science and Technology
    National Defense Academy

Selected Publications

  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

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

    Springer

  1. 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

    Vol. 2025 , no. 3 , pp. 516–576

    DOI Slides Code
  1. 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

    Vol. 2025 , no. 4 , pp. 70–124

    DOI Slides
  1. ACSAC
    Gravity of the Situation: Security Analysis on Rocket.Chat E2EE

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

    IEEE Annual Computer Security Applications Conference, ACSAC 2025, Honolulu, HI, USA, December 8-12, 2025, 2025

    pp. 15–30 · IEEE

    DOI Slides Code Website
  1. EuroS&P
    Not in The Prophecies: Practical Attacks on Nostr

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

    10th IEEE European Symposium on Security and Privacy, EuroS&P 2025, Venice, Italy, June 30 - July 4, 2025, 2025

    pp. 585–606 · IEEE

    DOI Code Website
  1. ASIACRYPT
    Key Collisions on AES and Its Applications

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

    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

    Vol. 15490 , pp. 267–300 · Springer

    DOI Slides
  1. 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

    Vol. 2023 , no. 2 , pp. 115–154

    DOI Slides Code
  1. 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

    Vol. 2023 , no. 4 , pp. 452–488

    DOI Slides
  1. 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

    Vol. 2022 , no. 3 , pp. 123–151

    DOI Slides Code
  1. 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

    Vol. 2022 , no. 3 , pp. 152–190

    DOI Slides Code
  1. ESORICS
    Security Analysis of SFrame

    Takanori Isobe, Ryoma Ito, and Kazuhiko Minematsu

    Computer Security - ESORICS 2021 - 26th European Symposium on Research in Computer Security, Darmstadt, Germany, October 4-8, 2021, Proceedings, Part II, 2021

    Vol. 12973 , pp. 127–146 · Springer

    DOI Slides
  1. FSE
    New Linear Correlations Related to State Information of RC4 PRGA Using IV in WPA

    Ryoma Ito, and Atsuko Miyaji

    Fast Software Encryption - 22nd International Workshop, FSE 2015, Istanbul, Turkey, March 8-11, 2015, Revised Selected Papers, 2015

    Vol. 9054 , pp. 557–576 · Springer

    DOI Slides

For other publications, please see the complete publications list.

Selected Talks

Black Hat
Payload Compromised: Full Key Recovery in Rocket.Chat E2EE

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

Black Hat Asia 2026 Briefings

· Speaker: Hayato Kimura

Website Slides
Black Hat
Not Sealed: Practical Attacks on Nostr, a Decentralized Censorship-Resistant Protocol

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

Black Hat USA 2025 Briefings

· Speaker: Hayato Kimura

Acceptance rate: 8.2% (93/1,143).

Website Slides

For other talks, please see the complete talks list.

Awards

  • 2026

    Japan

    ICSS Research Award
    ICSS group of IEICE
  • 2026

    Japan

    SCIS Paper Award
    SCIS 2025, ISEC group of IEICE
  • 2025

    Japan

    CSS Best Paper Award
    CSS 2025, IPSJ
  • 2025

    Japan

    SCIS Innovation Paper Award
    SCIS 2024, ISEC group of IEICE
  • 2024

    Japan

    CSS Paper Award
    CSS 2024, IPSJ
  • 2024

    Japan

    CSS Ethical Practice Award
    CSS 2024, IPSJ
  • 2024

    Japan

    CSS Student Paper Award
    CSS 2023, IPSJ
  • 2023

    Japan

    JIP Specially Selected Paper Certificate
    IPSJ
  • 2023

    Japan

    IPSJ Yamashita SIG Research Award
    IPSJ
  • 2022

    Japan

    SCIS Innovation Paper Award
    SCIS 2021, ISEC group of IEICE
  • 2021

    Japan

    CSS Encouragement Research Award
    CSS 2021, IPSJ
  • 2016

    Japan

    SCIS Paper Award
    SCIS 2015, ISEC group of IEICE
  • 2015

    Japan

    Best Student Award
    Japan Advanced Institute of Science and Technology
  • 2009

    Japan

    Best Student Award
    National Defense Academy

Academic Service

Editorial Board

  • 2025/2026
    Editorial Board Member
    IACR Transactions on Symmetric Cryptology
  • 2024/2025
    Editorial Board Member
    IACR Transactions on Symmetric Cryptology
  • 2023/2024
    Editorial Board Member
    IACR Transactions on Symmetric Cryptology
  • 2022/2023
    Editorial Board Member
    IACR Transactions on Symmetric Cryptology

Program Committee

  • 2026
    Program Committee Member
    FSE 2026
  • 2025
    Program Committee Member
    FSE 2025
  • 2024
    Program Committee Member
    ACISP 2024, ADSC 2024, FSE 2024, ISC 2024
  • 2023
    Program Committee Member
    ADSC 2023, FSE 2023

Conference Organization

  • 2024
    Publication Chair
    IWSEC 2024
  • 2023
    Local Organizing Chair
    ACNS 2023
  • 2022
    Publicity Chair
    ISPEC 2022
  • 2021
    Local Organizing Chair
    ACNS 2021

Lectures

  • 2026

    Japan

    Social Informatics (in Japanese)
    Toho University
  • 2026

    Japan

    An Introduction to Cryptography (in Japanese)
    Society of Automotive Engineers of Japan, Inc.
  • 2025

    Japan

    Social Informatics (in Japanese)
    Toho University
  • 2025

    Japan

    An Introduction to Cryptography (in Japanese)
    Society of Automotive Engineers of Japan, Inc.
  • 2024

    Japan

    An Introduction to Cryptography (in Japanese)
    Society of Automotive Engineers of Japan, Inc.
  • 2023

    Japan

    An Introduction to Cryptography (in Japanese)
    Society of Automotive Engineers of Japan, Inc.
  • 2022

    Japan

    An Introduction to Cryptography (in Japanese)
    Society of Automotive Engineers of Japan, Inc.