Study on the provable security and standardization of blockcipher mode of operation

• Project/Area Number: 18680001
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Fundamental theory of informatics
• Research Institution: Nagoya University
• Principal Investigator: IWATA Tetsu Nagoya University, 大学院・工学研究科, 准教授 (90344837)
• Project Period (FY): 2006 – 2008
• Project Status: Completed (Fiscal Year 2008)
• Budget Amount: ¥13,130,000 (Direct Cost: ¥10,100,000、Indirect Cost: ¥3,030,000); Fiscal Year 2008: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2007: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000); Fiscal Year 2006: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
• Keywords: 暗号理論 / 共通鍵暗号系 / ブロック暗号 / 利用モード / 暗号化モード / メッセージ認証コード / 認証暗号化 / 証明可能安全性 / 暗号・認証等 / 情報基礎 / 標準化 / CENC

Research Abstract

本研究では、主に以下の研究成果を得た。
(1)暗号化モードCENCの詳細な安全性の検討を行った。鍵系列と乱数を識別する敵の存在を示し、その成功確率を導いた。
(2)次に、認証暗号化モードCHMの認証子の計算過程に改良を加え、安全性を向上させた方式を設計した。
(3)最後に、メッセージ認証方式CMAC及びEMACについて、鍵チェック値との併用時に起こる安全性の問題点を指摘した。また、これらの脆弱性を回避する方法を提案した。

Research Products

• [Journal Article] Security of the five-round KASUMI type permutation (2008)
  • Author(s): Tetsu Iwata, Tohru Yagi, Kaoru Kurosawa
  • Journal Title: IEICE Trans. Fundamentals Vol. E91-A, No. 1 Pages: 30-38
  • NAID: 10026846523
  • Peer Reviewed
• [Journal Article] Security of the five-round KASUMI type permutation (2008)
  • Author(s): Tetsu Iwata, Tohru Yagi, Kaoru Kurosawa
  • Journal Title: IEICE Trans. Fundamentals Vol.E91-A,No.1 Pages: 30-38
  • NAID: 10026846523
  • Peer Reviewed
• [Journal Article] How to construct super-pseudorandom permutations with short keys (2007)
  • Author(s): Tetsu Iwata and Kaoru Kurosawa
  • Journal Title: IEICE Trans. Fundamentals Vol.E90-A, No. 1 Pages: 2-13
  • NAID: 110007519068
  • Peer Reviewed
• [Journal Article] How to construct super-pseudorandom permutations with short keys (2007)
  • Author(s): Tetsu Iwata, Kaoru Kurosawa
  • Journal Title: IEICE Trans. Fundamentals Vol. E90-A, No. 1 Pages: 2-13
  • NAID: 110007519068
• [Journal Article] Side channel attacks on message authentication codes (2006)
  • Author(s): Katsuyuki Okeya and Tetsu Iwata
  • Journal Title: IPSJ Journal Vol. 47, No. 8 Pages: 2571-2581
  • NAID: 130000058365
  • Peer Reviewed
• [Journal Article] Side channel attacks on message authentication codes (2006)
  • Author(s): Katsuyuki Okeya, Tetsu Iwata
  • Journal Title: IPSJ Journal Vol. 47, No. 8 Pages: 2571-2581
  • NAID: 130000058365
• [Journal Article] CENC : Overview and Tightness of the Security Bound
  • Author(s): Tetsu Iwata
  • Journal Title: Dagstuhl Seminar Proceedings 07021(印刷中)
• [Presentation] On the impact of key check value on CBC MACs and others (2009)
  • Author(s): Tetsu Iwata
  • Organizer: Dagstuhl Seminar, Symmetric Cryptography
  • Place of Presentation: Dagstuhl, Germany
• [Presentation] On the impact of key check value on CBC MACs and others (2009)
  • Author(s): Tetsu Iwata
  • Organizer: Dagstuhl Seminar, Symmetric Cryptography
  • Place of Presentation: ドイツダグスタール
• [Presentation] Tweakable pseudorandom permutation from generalized Feistel structure (2008)
  • Author(s): Atsushi Mitsuda and Tetsu Iwata
  • Organizer: Second International Conference, ProvSec 2008, LNCS 5342, Springer
  • Place of Presentation: Shanghai, China
• [Presentation] Bounds on fixed input/output length post-processing functions for biased physical random number generators (2008)
  • Author(s): Kyohei Suzuki and Tetsu Iwata
  • Organizer: Selected Areas in Cryptography, SAC 2008
  • Place of Presentation: Moncton, Canada
• [Presentation] Authenticated encryption mode for beyond the birthday bound security (2008)
  • Author(s): Tetsu Iwata
  • Organizer: Progress in Cryptology, AFRICACRYPT 2008, LNCS 5023, Springer
  • Place of Presentation: Casablanca, Morocco
• [Presentation] Authenticated encryption mode for beyond the birthday bound security (2008)
  • Author(s): Tetsu Iwata
  • Organizer: ESC, Echternach Symmetric Crypto Seminar
  • Place of Presentation: Echternach, Luxembourg
• [Presentation] Authenticated encryption mode for beyond the birthday bound security (2008)
  • Author(s): Tetsu Iwata
  • Organizer: Progress in Cryptology-AFRICACRYPT 2008
  • Place of Presentation: モロッコカサブランカ
• [Presentation] Bounds on fixed input/output length post-processing functions for biased physical random number generators (2008)
  • Author(s): Kyohei Suzuki, Tetsu, Iwata
  • Organizer: Selected Areas in Cryptography, SAC 2008
  • Place of Presentation: カナダモンクトン
• [Presentation] Tweakable pseudorandom permutation from generalized Feistel structure (2008)
  • Author(s): Atsushi Mitsuda, Tetsu Iwata
  • Organizer: Second International Conference, ProvSec 2008
  • Place of Presentation: 中国上海
• [Presentation] Tightness of the security bound of CENC (2007)
  • Author(s): Tetsu Iwata
  • Organizer: Dagstuhl Seminar Proceedings, 07021, Symmetric Cryptography
  • URL: http://drops.dagstuhl.de/opus/volltexte/2007/1016/
  • Place of Presentation: Dagstuhl, Germany