本文研究了形如fμ(x)=Tr(μxd)的n元单项布尔函数,其中d=2i+2j+1,μ∈GF(2n)*,i,j均为正整数,且n〉i〉工已有结论表明:当n〉2i时,L(x)具有良好的二阶非线性度下界.在此基础上本文研究了n≤2i时fμ(x)所有导数的非线性度下界,并给出n≤2i时fμ(x)的二阶非线性度下界.结果表明n≤2i时fμ(x)的二阶非线性度下界比n〉2i时fμ(x)的二阶非线性度下界更紧.因此,fμ(x)无论在n〉2i还是n≤2i时都可以抵抗二次函数逼近和仿射逼近攻击.
Abstract: This paper investigates cubic monomial Boolean functions fμ (x) = Tr (IXXd) with n variables, where d =21 +2j + 1,μ∈GF(2n) * , and n 〉 i 〉j. The known results show that the Boolean functionsfμ,(x) has good lower bounds on the second nonlinearity for n 〉 2i. This paper firstly studies all lower bounds on the nonlinearity of the derivatives off,(x), then the lower bounds on the second order nonlinearity off,(x) for n≤2i are given. The results show that the lower bounds on the second order nonlinearity off, (x) for n ≤2i are tighter than that of fμ(x) for n 〉2i. Therefore, whether n 〉2i or n〈.2i, the Boolean functionsf,,(x) can resist quadratic or linear approximation attacks.