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Bogdanov等人在2011年亚密会上提出了一种新的针对分组密码的密钥恢复攻击,称为biclique攻击,该攻击方法在构造biclique结构的基础上结合了中间相遇攻击的思想,可以有效降低攻击的时间复杂度和数据复杂度.此后这一方法被广泛用于分组密码的安全性分析.mCrypton作为一种新的能够在资源有限的硬件环境下高效运行轻量级分组密码,其安全性备受关注.本文首先介绍了biclique攻击的一般方法,并给出了一个d维biclique的完整定义.接着,我们说明了如何通过分析密码的密钥扩展算法,找出两条较短的且相互独立的差分路径,进而完成biclique结构的构造并利用该biclique结构进行全轮攻击.在此基础上,我们给出轻量级分组密码mCrypton-64的算法描述,并利用biclique攻击对其进行分析.mCrypton-64整体采用了SP结构,其分组长度为64比特,密钥长度为64比特,其加密过程包括非线性替换、比特置换、行列换位和密钥加.最后,我们针对mCrypton-64的密钥扩展算法找到了两条相互独立的差分路径,进而构造出一个11~12轮的4维biclique,利用它对全轮mCrypton-64进行了攻击,攻击的数据复杂度为2~(32),计算复杂度为2~(63.115),均好于已有的结果.
Bogdanov et al proposed a new key recovery attack for block cipher at the 2011 conference in Asia, called the biclique attack, which based on constructing the biclique structure, combined with the idea of intermediate encounter attack, can effectively reduce Attack time complexity and data complexity.After this method is widely used in packet-based password security analysis.Mcrypton as a new hardware and software resources in the limited hardware environment can efficiently run lightweight block cipher, its security This article first introduces the general method of biclique attacks and gives a complete definition of a d-dimensional biclique.Next, we show how to find out two short and mutual Independent differential path to complete the structure of biclique structure and use this biclique structure for all-round attack.On the basis of this, we give a description of the algorithm of lightweight block cipher mCrypton-64 and analyze it with biclique attack. mCrypton-64 adopts SP structure as a whole, its packet length is 64 bits, its key length is 64 bits, its encryption process includes non-linear replacement, bit Replacement, row and column keys and key addition.Finally, we find two independent differential paths for the key expansion algorithm of mCrypton-64, and then construct a four-dimensional biclique of 11 to 12 rounds, mCrypton-64 attack, the attack data complexity is 2 ~ (32), the computational complexity is 2 ~ (63.115), are better than the existing results.