Acta Scientiarum Naturalium Universitatis Pekinensis

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Two Attacks on 5-Round IDEA

LU Linzhen, CHEN Shaozhen   

  1. Department of Applied Mathematics, Institute of Information Engineering, Information Engineering University, Zhengzhou 450002;
  • Received:2010-05-13 Online:2010-09-20 Published:2010-09-20



  1. 信息工程大学信息工程学院应用数学系, 郑州 450002;

Abstract: Using the linear property of the key schedule algorithm, the authors give a related-key attack on 5-round IDEA (the international data encryption algorithm) that has a time complexity of 270.5 5-round IDEA encryptions, and then present an improved meet-in-the-middle attack, which on 5-round variant of IDEA only requires 27 chosen plaintexts and 2120 5-round IDEA encryptions.

Key words: block cipher, IDEA, cryptanalysis, related-key

摘要: 利用IDEA密钥扩展算法的线性特点,结合IDEA算法的性质提出了两种对5轮IDEA算法的攻击。第 1 种攻击采用相关密钥的思想,计算复杂度约为270.5 次加密5 轮IDEA 算法;第27种攻击利用密钥特点, 攻击5轮仅需要27个选择明文, 计算复杂度约为2120 次加密 5 轮 IDEA 算法。

关键词: 分组密码, IDEA, 密码分析, 相关密钥

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