The GSM Standard (An overview of its security)

Global System for Mobile Communications (GSM) is the most popular mobile phone system in the world, accounting for 70% of the world's digital mobile phones. According to a press release by the GSM Association in May 2001, there are more than half a billion GSM mobile phones in use in over 168 countries today. The phenomenal success in mobile telecommunications is due in large to GSM. One of its key strength is its international roaming capability, giving consumers a seamless service in over 168 countries.