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为评估一类广义Feistel密码的安全性能,通过列举的方法,对该分组密码抵抗差分密码分析和线性密码分析的能力进行了深入研究.在轮函数是双射的假设条件下,证明了4,8,12,16轮广义Feistel密码分别至少有2,5,8,10个轮函数的输入差分非零;证明了4r(r≥2)轮广义Feistel密码至少有2r+1个轮函数的输入差分非零.从而若设轮函数的最大差分和线性特征的概率分别为p和q,则4r(r≥2)轮广义Feistel密码的差分特征和线性特征的概率分别以p2r+1和q2r+1为其上界.
In order to evaluate the security performance of a class of generalized Feistel ciphers, the ability of the cipher cipher to resist differential cryptanalysis and linear cryptanalysis is studied in detail by enumerated methods. Under the assumption that the round function is bijective, 8, 12, 16 generalized Feistel ciphers at least 2, 5, 8, and 10 round functions respectively. The input differential of at least 2r + 1 round functions is proved for 4r (r≥2) rounds of generalized Feistel ciphers So that if the probability of the maximum difference and the linear feature of the wheel function is p and q respectively, then the probability of the differential feature and the linear feature of the generalized Feistel code with 4r (r≥2) rounds is respectively expressed by p2r + 1 and q2r + 1 for its upper bound.