分组密码TWIS的三子集中间相遇攻击

3-subset meet-in-the-middle attack on block cipher TWIS

对轻量级分组密码TWIS的安全性做进一步分析,将三子集中间相遇攻击应用于忽略后期白化过程的10轮TWIS。基于TWIS密钥生成策略中存在的缺陷,即其实际密钥长度仅为62 bit且初始密钥混淆速度慢,攻击恢复10轮TWIS全部62 bit密钥的计算复杂度为245,数据复杂度达到最低,仅为一个已知明密文对。分析结果表明TWIS在三子集中间相遇攻击下是不安全的。

To do further analysis of the security of lightweight block cipher TWIS, 3-subset meet-in-the-middle attack was applied to 10-round TWIS without the final whitening. Based on the weakness in the key schedule of TWIS： its ac- tual key size was only 62-bit and the confusion speed of the initial key was rather slow, the time complexity to recover the whole 62-bit key of 10-round TWIS was 245, and the data complexity was low enough with only one known plain- text-ciphertext pair. The result shows that block cipher TWlS is not secure under 3-subset meet-in-the-middle attack.