In this book, the security algorithms for wireless communications were discussed. Then different algorithms of global system for mobile communications (GSM) and their work have been analysed using qualitative method that we conducted our research which was the research methodology we used for this study.GSM was one of the first digital mobile phone systems to follow the analogue era. Widely known problems with GSMs analogue counter parts were the possibility of phone fraud through cloning phones and thus calling in someone elses expense, and the possibility of someone intercepting the phone...