Contraction Sequence, Period And Linear Complexity Of Analysis

The clock-conctolled Generator is a significant part of stream cipher cryptosystems. And the self-shrinking generator is a typical model of the clock-conctolled During the past ten years or more, some researches have been done on the period and linear complexity of the self-shrinking sequence obtained from an m-sequence which is generated by a primitive polynomial f(x) over GF(2), degree(f)=n , in the related academies.We have known the period of the self-shrinking sequence is multiple of 2[n/2], and the linear complexity of is at leastThis paper, further more, makes a study of the period and the linear complexity of the output of a self-shrinking generator based on an n-stage m-sequence. It proves that the period of za obtained from an n-stage m-sequence a is the multiple of 2[n/2]+1. That is to say, it provesthat the linear complexity of the output of a self-shrinking generator based on an n-stage m-sequence L(za) > 2[n/2]+ 1, and tl larger than the previous conclusion.m-sequence L(za) > 2[n/2]+ 1, and the lower boundary of the linear complexity is two times...