Secure end-to-end communication over GSM and PSTN networks

GSM (Global System for Mobiles) is the most widely spread mobile communication system in the world. An important objective in mobile communication systems is secure speech communication. GSM suffers from various security weaknesses. The GSM voice traffic is secure outside the core network but it has no security over the core network. This system can be made thoroughly secure by encrypting the speech which is to be transmitted on the GSM voice channel. In this paper we have demonstrated a real-time prototype of an end-to-end secure communication system developed in MATLAB Simulink. Our technique comprises of encryption of the speech before entering the GSM handset which adds security and confidentiality to our communication. The encryption algorithm is private to the communicating GSM subscribers and even the service providing company will not judge what was said. This is amazing because now the GSM channel will become exclusively concealed and confidential to the two subscribers so that even the company people cannot listen to them.