Fuzzy Logic Based Complexity Evaluation of Stream Cipher Systems

This paper is proposing an “evaluation method “for a pseudo – random sequences based on fuzzy rules. The Fuzzy rules are designed taken into considerations two main parameters, which are, the length of the maximum period that can be obtained from the linear feedback shift register, and the second parameter is the Entropy of the resulted maximum period of the sequences obtained from different length shift register.The proposed method was applied on the summation generator firstly on its original well known form (with one bit memory) and then we developed the summation generator itself by varying the number of the delayed bits by two and by three. All the results of the complexity measures are compared to the complexity results obtained from the well known “Berlkamp Massey Method “. A promising result is obtained, that give us a good indication for the performance for the proposed method.

کلیدواژه ها:

Fuzzy Logic ، Stream cipher system ، evaluation techniques ، summation generator ، complexity theory