Three-Subset Meet-in-the-Middle Attack on Reduced XTEA
Three-Subset Meet-in-the-Middle Attack on Reduced XTEA
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DOI：
10.1007/978-3-642-31410-0_9
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发表时间：
2012-07
期刊：
影响因子：
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通讯作者：
Yu Sasaki;Lei Wang;Yasuhide Sakai;K. Sakiyama;K. Ohta
中科院分区：
文献类型：
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作者：
Yu Sasaki;Lei Wang;Yasuhide Sakai;K. Sakiyama;K. Ohta
提出了一种改进的基于三子集中间相遇（MitM）的分组密码XTEA单密钥攻击。首先，讨论了一种通用分组密码技术。指出了以往的工作应用拼接切割技术的三子集的MitM攻击包含不完整的参数，因此它需要非常大的数据复杂度，这是接近的代码书。本文给出了一个修正的过程，以保持数据的复杂性小。其次，对具有64轮Feistel网络和128位密钥的64位分组密码XTEA进行了三子集MitM攻击。使用9个已知明文和2120.40XTEA计算攻击25轮，而之前最好的单密钥攻击仅达到23轮。在选择明文模型下，攻击扩展到28轮，237个选择明文和2120.38次计算。
This paper presents an improved single-key attack on a block-cipher XTEA by using the three-subset meet-in-the-middle (MitM) attack. Firstly, a technique on a generic block-cipher is discussed. It points out that the previous work applying the splice-and-cut technique to the three-subset MitM attack contains incomplete arguments, and thus it requires a very large data complexity, which is close to the code book. This paper gives a corrected procedure to keep the data complexity small. Secondly, the three-subset MitM attack is applied for reduced-round XTEA, which is a 64-bit block-cipher with 64-round Feistel network and a 128-bit key. 25 rounds are attacked with 9 known plaintexts and 2120.40XTEA computations, while the previous best single-key attack only reaches 23 rounds. In the chosen-plaintext model, the attack is extended to 28 rounds with 237chosen-plaintexts and 2120.38computations.