Rijndael分组密码与差分攻击

深入研究了Rijndael分组密码,将字节代替变换中的有限域GF(28)上模乘求逆运算和仿射变换归并成了一个8×8的S盒,将圈中以字节为单位进行的行移位、列混合、密钥加三种运算归并成了一个广义仿射变换.基于归并将Rijndael密码算法了进行简化,结果表明Rijndael密码实质上是一个形如仿射变换Y=A(?)S(X)(?)K的非线性迭代算法,并以分组长度128比特、密钥长度128比特作为特例,给出了二轮Rijndael密码的差分攻击.文中还给出了Rijndael密码算法的精简描述,并指出了算法通过预计算快速实现的有效方法.

Research on Rijndael Block Cipher and Differential Attack

This paper makes a further study on Rijndael block cipher. The computation of inverse and affine permutation over GF(28) in ByteSub permutation are merged into a 8x8 S-box and the operation of ShiftRow, MixCol and AddRoundKey in round transformation are merged into a general affine permutation. After simplification on the basis of mergence, it results that Rijndael cipher is substantially a nonlinear recurrence algorithm of affine permutation like Y=A(?)S(X)(?)K, which is illustrated with 128 bit block and 128 bit key by giving its two-round differential attack. In addition, a simplified depiction of Rijndael algorithm is offered and an effective way to implement this algorithm rapidly by pre-computation is prosed.