关于广义自缩序列的最小周期  

Least Periods of Generalized Self-Shrinking Sequences

作　　者：周建钦[1] 孙国华[1] 

机构地区：[1]安徽工业大学计算机学院,安徽马鞍山243002

出　　处：《微电子学与计算机》2007年第6期214-217,共4页Microelectronics & Computer

基　　金：国家自然科学基金项目(60473142)

摘　　要：伪随机性是密钥序列的不可预测性的重要度量指标。通过选择适当的比特串并分析其个数的奇偶性,证明了广义自缩序列b(a_(k-1))和b(a_(k+1))的最小周期达到最大,即2^(n-1)。类似地,讨论若干类广义自缩序列的最小周期,如:b(a_(k-1)+a_(k+2)),b(a_(k-2)+a_(k-1)),b(a_(k-2)+a_(k+2)),…等,在大多数情形下证明了它们的最小周期达到最大,即2^(n-1)。Stream ciphers use binary sequences with good pseudo randomness as key streams to enerypt messages. By analysing the appearing times of the bit string ＂101＂ in generalized self-shrinking sequences b （ak-l） and b （ak＋l）, it is proved that their least periods reach the maximum, namely 2^ （n-1）. In the same way, we discuss the least periods of generalized self-shrinking sequences b （ak-l＋ak＋2）,b （ak-2＋ak-l）,b （ak-2＋ak＋2）, ...,etc, it is proved that in most cases their least periods reach the maximum.

关 键 词：序列密码 M-序列 广义自缩序列 最小周期 

分 类 号：TP918.1[自动化与计算机技术]