Study on Highly Secure and Efficient Symmetric Key Cryptosyste

• Project/Area Number: 22680001
• 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 名古屋大学, 工学研究科, 准教授 (90344837)
• Project Period (FY): 2010 – 2012
• Project Status: Completed (Fiscal Year 2012)
• Budget Amount: ¥11,700,000 (Direct Cost: ¥9,000,000、Indirect Cost: ¥2,700,000); Fiscal Year 2012: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000); Fiscal Year 2011: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000); Fiscal Year 2010: ¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
• Keywords: 暗号系 / 共通鍵暗号 / ブロック暗号 / 利用モード / 共通鍵番号

Research Abstract

We obtain the following main results.
・We propose a construction of a tweakable block cipher whose block length is shorter or longer than 2n bits, from an n-bit tweakable block cipher.
・ We propose constructions of a permutation layer for Type-1 generalized Feistel structures so that they have a good diffusion property.
・We show that EAX-prime allows various efficient attacks. We also prove its security if the input data called a cleartext is always longer than the block length of theunderlying block cipher.
・We show that the original security proof of GCM contains a flaw. We also show that the flaw can be fixed and therefore GCM maintains its provable security.

Research Products

• [Journal Article] Improving the Permutation Layer of Type 1, Type 3, Source-Heavy, and Target-Heavy Generalized Feistel Structures (2013)
  • Author(s): Shingo Yanagihara and Tetsu Iwata
  • Journal Title: IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences Volume: E96.A Issue: 1 Pages: 2-14
  • DOI: 10.1587/transfun.E96.A.2
  • NAID: 10031167083
  • ISSN: 0916-8508, 1745-1337
  • Peer Reviewed
• [Journal Article] Security of Hash-then-CBC Key Wrapping Revisited (2013)
  • Author(s): Yasushi Osaki and Tetsu Iwata
  • Journal Title: IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences Volume: E96.A Issue: 1 Pages: 25-34
  • DOI: 10.1587/transfun.E96.A.25
  • NAID: 10031167085
  • ISSN: 0916-8508, 1745-1337
  • Peer Reviewed
• [Journal Article] Further More on Key Wrapping (2012)
  • Author(s): Yasushi Osaki and Tetsu Iwata
  • Journal Title: IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences Volume: E95-A Issue: 1 Pages: 8-20
  • DOI: 10.1587/transfun.E95.A.8
  • NAID: 10030534377
  • ISSN: 0916-8508, 1745-1337
  • Peer Reviewed
• [Presentation] Type 1.x generalized Feistel structures (2013)
  • Author(s): Shingo Yanagihara
  • Organizer: Pre-proceedings of International Workshop on Coding and Cryptography, WCC 2013
  • Place of Presentation: Bergen, Norway
• [Presentation] Attacks and security proofs of EAX-prime (2013)
  • Author(s): Kazuhiko Minematsu
  • Organizer: Fast Software Encryption, FSE 2013, LNCS, Springer-Verlag
  • Place of Presentation: Singapore.
• [Presentation] OKH 認証暗号化方式に対する攻撃 (2013)
  • Author(s): 小林 隼人
  • Organizer: 2013 年暗号と情報セキュリティシンポジウム,SCIS 2013, 1B2-2
  • Place of Presentation: 京都市
• [Presentation] SGCM のカウンタ衝突確率 (2013)
  • Author(s): 大橋 佳祐
  • Organizer: 2013 年暗号と情報セキュリティシンポジウム,SCIS 2013, 1B2-1
  • Place of Presentation: 京都市
• [Presentation] SGCMのカウンタ衝突確率 (2013)
  • Author(s): 大橋 佳祐
  • Organizer: 2013年暗号と情報セキュリティシンポジウム，SCIS 2013
  • Place of Presentation: 京都
• [Presentation] OKH認証暗号化方式に対する攻撃 (2013)
  • Author(s): 小林 隼人
  • Organizer: 2013年暗号と情報セキュリティシンポジウム，SCIS 2013
  • Place of Presentation: 京都
• [Presentation] Attacks and security proofs of EAX-prime (2013)
  • Author(s): Kazuhiko Minematsu
  • Organizer: Fast Software Encryption, FSE 2013
  • Place of Presentation: Singapore
• [Presentation] Type 1.x generalized Feistel structures (2013)
  • Author(s): Shingo Yanagihara
  • Organizer: International Workshop on Coding and Cryptography, WCC 2013
  • Place of Presentation: Bergen, Norway
• [Presentation] Type 1,Type 3一般化Feistel構造の置換層の改良 (2012)
  • Author(s): 柳原慎吾
  • Organizer: 2012年暗号と情報セキュリティシンポジウム(SCIS2012)
  • Place of Presentation: 金沢エクセルホテル東急(石川県)
  • Year and Date: 2012-01-31
• [Presentation] Breaking and repairing GCM security proofs (2012)
  • Author(s): Tetsu Iwata
  • Organizer: Advances in Cryptology, CRYPTO 2012, LNCS 7417、Springer-Verlag
  • Place of Presentation: Santa Barbara,USA
• [Presentation] How fast can a two-pass mode go? A parallel deterministic authenticated encryption mode for AES-NI (Extended abstract of work in progress) (2012)
  • Author(s): Kazumaro Aoki
  • Organizer: Workshop records of DIAC, Directions in Authenticated Ciphers
  • Place of Presentation: Stockholm, Sweden
• [Presentation] Cryptanalysis of EAX-prime. Workshop records of DIAC (2012)
  • Author(s): Kazuhiko Minematsu
  • Organizer: Directions in Authenticated Ciphers
  • Place of Presentation: Stockholm, Sweden
• [Presentation] Cryptanalysis of 256-bit key HyRAL via equivalent keys (2012)
  • Author(s): Yuki Asano
  • Organizer: ACNS 2012, LNCS 7341、Springer-Verlag
  • Place of Presentation: Singapor
• [Presentation] Type 1, Type 3 一般化Feistel 構造の置換層の改良 (2012)
  • Author(s): 柳原 慎吾
  • Organizer: 2012 年暗号と情報セキュリティシンポジウム,SCIS 2012, 2C1-2
  • Place of Presentation: 石川県金沢市
• [Presentation] Cryptanalysis of 256-bit key HyRAL via equivalent keys (2012)
  • Author(s): Yuki Asano
  • Organizer: Applied Cryptography and Network Security, ACNS 2012
  • Place of Presentation: Singapore
• [Presentation] Cryptanalysis of EAX-prime (2012)
  • Author(s): Kazuhiko Minematsu
  • Organizer: DIAC, Directions in Authenticated Ciphers
  • Place of Presentation: Stockholm, Sweden
• [Presentation] How fast can a two-pass mode go? A parallel deterministic authenticated encryption mode for AES-NI (Extended abstract of work in progress) (2012)
  • Author(s): Kazumaro Aoki
  • Organizer: DIAC, Directions in Authenticated Ciphers
  • Place of Presentation: Stockholm, Sweden
• [Presentation] Breaking and repairing GCM security proofs (2012)
  • Author(s): Tetsu Iwata
  • Organizer: Advances in Cryptology, CRYPTO 2012
  • Place of Presentation: Santa Barbara, USA
• [Presentation] Building Blockcipher from Tweakable Blockcipher : Extending FSE 2009 Proposal (2011)
  • Author(s): Tetsu Iwata
  • Organizer: The 13th IMA International Conference on Cryptography and Coding (IMACC 2011)
  • Place of Presentation: Oxford University (UK)
  • Year and Date: 2011-12-15
• [Presentation] Security of Hash-then-CBC Key wrapping revisited (2011)
  • Author(s): Yasushi Osaki
  • Organizer: The 13th IMA International Conference on Cryptography and Coding (IMACC 2011)
  • Place of Presentation: Oxford University (UK)
  • Year and Date: 2011-12-15
• [Presentation] On permutation layer of Type 1, Source-Heavy, Target-Heavy Generalized Feistel structures (2011)
  • Author(s): Shingo Yanagihara
  • Organizer: The 10th International Conference on Cryptology and Network Security (CANS 2011)
  • Place of Presentation: 三亜(中国)
  • Year and Date: 2011-12-10
• [Presentation] 249ビットHyRALの等価鍵 (2011)
  • Author(s): 浅野優貴
  • Organizer: コンピュータセキュリティシンポジウム2011(CSS2011)
  • Place of Presentation: 朱鷺メッセ(新潟県)
  • Year and Date: 2011-10-20
• [Presentation] Further More on Key Wrapping (2011)
  • Author(s): Yasushi Osaki
  • Organizer: Symmetric Key Encryption Workshop (SKEW) 2011
  • Place of Presentation: Lyngby, Denmark
  • Year and Date: 2011-02-17
• [Presentation] 暗号文長を削減可能なHtECB方式 (2011)
  • Author(s): 尾崎泰司
  • Organizer: 2011年暗号と情報セキュリティシンポジウム(SCIS2011)
  • Place of Presentation: リーガロイヤルホテル小倉(福岡県)
  • Year and Date: 2011-01-27
• [Presentation] Type1, Source-Heavy, Target-Heavy一般化Feistel構造の改良 (2011)
  • Author(s): 柳原慎吾
  • Organizer: 2011年暗号と情報セキュリティシンポジウム(SCIS2011)
  • Place of Presentation: リーガロイヤルホテル小倉(福岡県)
  • Year and Date: 2011-01-27
• [Presentation] Security of Hash-then-CBC key wrapping revisited. Cryptography and Coding (2011)
  • Author(s): Yasushi Osaki
  • Organizer: 13th IMA International Conference, IMACC 2011, LNCS 7089、Springer-Verlag
  • Place of Presentation: Oxford, UK
• [Presentation] Building blockcipher from tweakable blockcipher: Extending FSE 2009 proposal. Cryptography and Coding (2011)
  • Author(s): Tetsu Iwata
  • Organizer: 13th IMA International Conference, IMACC 2011, LNCS 7089、Springer-Verlag
  • Place of Presentation: Oxford, UK
• [Presentation] On permutation layer of Type 1, Source-Heavy, Target-Heavy Generalized Feistel structures (2011)
  • Author(s): Shingo Yanagihara
  • Organizer: The 10th International Conference on Cryptography and Network Security, CANS 2011, LNCS 7092,Springer-Verlag
  • Place of Presentation: Sanya, China
• [Presentation] 249 ビット鍵 HyRAL の等価鍵 (2011)
  • Author(s): 浅野 優
  • Organizer: コンピュータセキュリティシンポジウム 2011,CSS2011, 2C2-1
  • Place of Presentation: 新潟県新潟市
• [Presentation] Type 1, Source-Heavy, Target-Heavy 一般化 Feistel 構造の改良 (2011)
  • Author(s): 柳原 慎吾
  • Organizer: 2011年暗号と情報セキュリティシンポジウム,SCIS 2011, 3B2-3
  • Place of Presentation: 福岡県北九州市
• [Presentation] 暗号文長を削減可能なHtECB方式 (2011)
  • Author(s): 尾崎 泰司
  • Organizer: 2011年暗号と情報セキュリティシンポジウム, SCIS 2011, 3B2-4
  • Place of Presentation: 福岡県北九州市
• [Presentation] Further more on key wrapping (2011)
  • Author(s): Yasushi Osaki
  • Organizer: Conference record of Symmetric Key Encryption Workshop (SKEW) 2011
  • Place of Presentation: Lyngby, Denmark.