### Abstract

MISTY is a data encryption algorithm recently proposed by M. Matsui from Mitsubishi Electric Corporation. This paper focuses on cryptographic roles of the transform used in the MISTY cipher. Our research reveals that when used for constructing pseudorandom permutations, the transform employed by the MISTY cipher is inferior to the transform in DES, though the former is superior to the latter in terms of strength against linear and differential attacks. More specifically, we show that a 3-round (4-round, respectively) concatenation of transforms used in the MISTY cipher is not a pseudorandom (super pseudorandom, respectively) permutation. For comparison, we note that with three (four, respectively) rounds, transforms used in DES yield a pseudorandom (super pseudorandom, respectively) permutation. Another contribution of this paper is to show that a 3-round concatenation of transforms used in (the preliminary version of) the MISTY cipher has an algebraic property, which may open a door for various cryptanalytic attacks.

Original language | English |
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Title of host publication | Algorithms and Computation - 7th International Symposium, ISAAC 1996, Proceedings |

Editors | Hiroshi Nagamochi, Satoru Miyano, Tetsuo Asano, Yoshihide Igarashi, Subhash Suri |

Publisher | Springer Verlag |

Pages | 376-385 |

Number of pages | 10 |

ISBN (Print) | 3540620486, 9783540620488 |

Publication status | Published - Jan 1 1996 |

Event | 7th International Symposium on Algorithms and Computation, ISAAC 1996 - Osaka, Japan Duration: Dec 16 1996 → Dec 18 1996 |

### Publication series

Name | Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) |
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Volume | 1178 |

ISSN (Print) | 0302-9743 |

ISSN (Electronic) | 1611-3349 |

### Other

Other | 7th International Symposium on Algorithms and Computation, ISAAC 1996 |
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Country | Japan |

City | Osaka |

Period | 12/16/96 → 12/18/96 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

- Theoretical Computer Science
- Computer Science(all)

### Cite this

*Algorithms and Computation - 7th International Symposium, ISAAC 1996, Proceedings*(pp. 376-385). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 1178). Springer Verlag.

**Cryptographic weaknesses in the round transformation used in a block cipher with provable immunity against linear cryptanalysis.** / Sakurai, Kouichi; Zheng, Yuliang.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*Algorithms and Computation - 7th International Symposium, ISAAC 1996, Proceedings.*Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), vol. 1178, Springer Verlag, pp. 376-385, 7th International Symposium on Algorithms and Computation, ISAAC 1996, Osaka, Japan, 12/16/96.

}

TY - GEN

T1 - Cryptographic weaknesses in the round transformation used in a block cipher with provable immunity against linear cryptanalysis

AU - Sakurai, Kouichi

AU - Zheng, Yuliang

PY - 1996/1/1

Y1 - 1996/1/1

N2 - MISTY is a data encryption algorithm recently proposed by M. Matsui from Mitsubishi Electric Corporation. This paper focuses on cryptographic roles of the transform used in the MISTY cipher. Our research reveals that when used for constructing pseudorandom permutations, the transform employed by the MISTY cipher is inferior to the transform in DES, though the former is superior to the latter in terms of strength against linear and differential attacks. More specifically, we show that a 3-round (4-round, respectively) concatenation of transforms used in the MISTY cipher is not a pseudorandom (super pseudorandom, respectively) permutation. For comparison, we note that with three (four, respectively) rounds, transforms used in DES yield a pseudorandom (super pseudorandom, respectively) permutation. Another contribution of this paper is to show that a 3-round concatenation of transforms used in (the preliminary version of) the MISTY cipher has an algebraic property, which may open a door for various cryptanalytic attacks.

AB - MISTY is a data encryption algorithm recently proposed by M. Matsui from Mitsubishi Electric Corporation. This paper focuses on cryptographic roles of the transform used in the MISTY cipher. Our research reveals that when used for constructing pseudorandom permutations, the transform employed by the MISTY cipher is inferior to the transform in DES, though the former is superior to the latter in terms of strength against linear and differential attacks. More specifically, we show that a 3-round (4-round, respectively) concatenation of transforms used in the MISTY cipher is not a pseudorandom (super pseudorandom, respectively) permutation. For comparison, we note that with three (four, respectively) rounds, transforms used in DES yield a pseudorandom (super pseudorandom, respectively) permutation. Another contribution of this paper is to show that a 3-round concatenation of transforms used in (the preliminary version of) the MISTY cipher has an algebraic property, which may open a door for various cryptanalytic attacks.

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UR - http://www.scopus.com/inward/citedby.url?scp=84990204529&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:84990204529

SN - 3540620486

SN - 9783540620488

T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

SP - 376

EP - 385

BT - Algorithms and Computation - 7th International Symposium, ISAAC 1996, Proceedings

A2 - Nagamochi, Hiroshi

A2 - Miyano, Satoru

A2 - Asano, Tetsuo

A2 - Igarashi, Yoshihide

A2 - Suri, Subhash

PB - Springer Verlag

ER -