Many security mechanisms for mobile communications have been introduced in the literature. Among these mechanisms, a simple authentication technique for use in the GLObal MObility NETwork (GLOMONET) is proposed. Specifically, the wireless medium introduces new opportunities for eavesdropping of wireless data communications. Anyone with the appropriate wireless receiver can eavesdrop and this kind of eavesdropping is virtually undetectable. Global System for Mobile Communications (GSM) is a digital wireless network standard designed by standardization committees from major European telecommunications operators and manufacturers.