摘要
一、引言 在流密码学中,人们通常采用一个线性移位寄存器或多个线性移位寄存器再加一个滤波函数来作为流密钥序列生成器。非线性滤波函数的作用是为了提高流密钥序列的线性复杂度。Siegenthaler指出:如果滤波函数选择不当,破译者在仅知密文的情况下可以使用相关攻击的方法来攻击该体制。为了抵抗相关攻击的方法,Siegenthaler提出了相关免疫函数的概念,并给出开关函数是相关免疫函数的必要条件。肖国镇和J.L.
A sufficient and necessary condition for the swkch functions to be correlation-immune is derived by using the characteristic matrix.A characterization of the algebraic normal form of functions with correlation immunity is also presented by using the relationship between the minterm expression and algebraic normal form expression.Finally, a large number of correlation-immune functions of order 1 are constructed in this paper.
出处
《应用数学学报》
CSCD
北大核心
1991年第3期331-336,共6页
Acta Mathematicae Applicatae Sinica
