A simple and cheap end-to-end voice encryption framework over GSM-based networks

This paper presents a framework for voice encryption over GSM-based networks. To evaluate the framework, we have designed and implemented prototypes. The prototypes support full-duplex communication and real-time communication. To make the prototypes cheap and simple, the RC4 algorithm is utilized to protect digital of voice. The Bluetooth technology is utilized to communicate between the voice encryption prototype and a mobile phone. Because of using Bluetooth link, modification of mobile phone does not need and user interfaces do not need. The preliminary result of the prototype shows that the communication using prototypes is significantly secured and acceptable performance. In addition, the prototypes could be commercial products with very low cost. The cost of one prototype could be less than 40 US dollars.