Cryptanalysis of Stream Cipher System Using Particle Swarm Optimization Algorithm


The meaning of the Particle Swarm Optimization (PSO) refers to a relatively new family of algorithms that may be used to find optimal (or near optimal) solutions to numerical and qualitative problems.Stream ciphers are an important class of encryption algorithms. Shift register sequences are used in both cryptography and coding theory. There is a wealth of theory about them; stream ciphers based on shift registers have been the workhorse of military cryptography since the beginnings of electronics.This paper aims to implement cryptanalysis attack algorithms on stream cipher systems using plaintext attack (or part from it), choosing one Linear Feedback Shift Register (LFSR), since its considered as a basic unit of stream cipher systems, in the performance of PSO by solving Linear Equations System (LES) for any number of variables of the output of LFSR.The application divided into two stages, first, constructing LES’s for the LFSR, and the second, is attacking the variables of LES’s which they are also the initial key values the of LFSR.