In this paper, we study and develope a special secure Dongle to be adapted in GSM SmartPhone for secure voice communication to the serial 20-pin connector in SmartPhone. We design and implement the Dongle module hardware, firmware, and software including cipher crypto-synchronization and cipher algorithm. Also we study and emulate the SmartPhone GUI software interface including communication software module to the Dongle. Finally, we analyze the performances of crypto-synchronization in some noisy environment and also we test the secure Dongle module.