Improvement in the Interception Vulnerability Level of Encryption Mechanism in GSM

Abstract

Due to day-to-day advancements in the technology, cellular mobile operators around the world are facing higher data-rate demands and novel security issues. The emerging issues are basically the result of the evolving features of technology advancement. Therefore, there is an urgent need for specific modifications in the existing security mechanisms used in cellular communication systems, in order to enable them to face evolving security challenges. This thesis focuses on analysis the existing security mechanisms used in GSM (Global system for mobile) and proposes necessary modifications in them in order to enhance security. In GSM generally three linear feedback shift registers are used to fragment key in data encryption mechanism. In the dissertation, it is proposed that in order to improve the security, the number of registers is increased, then the number of combinations also increases. As combinations increase, the vulnerability of intercepting the encryption key decreases that enhances the security of the system. Moreover, a closed-form formula is developed to calculate the number of combinations of the session key if it is fragmented into a number of registers. The results are plotted to show the trends of the number of combinations and the vulnerability level of interception with respect to the number of registers. It is observed from the simulations that when the number of registers is increased, the number of combinations also increases; on the other hand the vulnerability level of interception decreases. In this way, personal data or information is protected and hacking of data becomes difficult. The derived formula can be used for the analysis of security mechanism in GSM, wireless sensor networks and internet of things (IOT).