“与密钥模2~n加运算”的差分性质研究

Differential Characteristic Probability of Added Key on Modulo 2~n Operation

"与密钥K模2n加"—Y=X+Kmod2n是密码算法中一个常用的基本编码环节,在SAFER++,RC6Phelix等算法中有广泛的应用。该文对Y=X+Kmod2n进行了差分分析,首次给出了当差分转移概率取最大值1,次大值1-1/2n-2,次小值1/2n-2以及1/2时,输入差,输出差及密钥的结构特点和计数公式。

Added key on modulo 2n operation—Y=X＋Kmod2n is a code link which is often used in cipher algorithms,as SAFER＋＋,RC6,Phelix and so on.In this paper,the Y=X＋Kmod2n is analyzed with differential cryptanalysis.And the characters of structure,counting formulas of input and output differences and the keys is given for the first time,when the differential probability is to be 1,1-1/2n-2,1/2n-2,1/2.