有限域上的逆函数左右复合一个仿射置换而成的仿射逆函数具有很好的密码学性质。文中讨论了仿射逆函数的输出分量函数所具有的线性等价性,给出了欧洲NESSIE计划的入选算法Camellia算法的S盒输出分量函数的统一等价表示,并证明这种线性等价表示是仿射逆函数所不能避免的。
Affine inverse functions derived from the inverse function composed with affine permutations possess good eryptographic properties. In this paper, the linear equivalence of output coordinate functions of affine inverse functions and the S-box of Camellia are discussed. It is proved that this equivalence in affine inverse functions can not be avoided wherever any affine permutations are used.