Simulink Based Implementation of Developed A5/1 Stream Cipher Cryptosystems

The major aim of this paper is to develop GSM networks security by working on improving of one of the elements of the GSM networks security which is A5/1 encryption algorithm. Since the development facilities of the MATLAB. Process depends on improving the implementation of clocking unit, change the implementation method of the majority function, increase the length of the key stream generator, decrease the time of computation, increase of entropy and develop the link of second register by avoiding three weaknesses that observed by Biham and Barkan in A5/1 in 2005 in the binding process, these processes are very important to increase the randomness of key stream generator and generate force key stream specifically by the used SIMULINK environment.According to our knowledge, this is the first time to develop a SIMULINK approach for realization the proposed developments of A5/1, and testing their validity of actual application in the real such field. Since the hardware realization is one of the great challenges facing the researchers working in the software field after finishing their implementation of their proposed software development. According to our opinion, this work in such approach offers the following: crossing the barrier separating the software specialists and hardware specialists, offering good background of hardware knowledge to the computer specialists working with this design of a developed key generator or cryptosystem, and offer great trust that the results of the developed algorithms can be applied without any obstacles.