Security in GPRS systems

Human beings had always dreamed of being able to communicate freely without thelimitations of time and place. This dream led the idea of mobile communication. Thanks tothe electronic systems, getting smaller, and the development of technology, telephones, whichwe had only in our homes and offices in the past, are now in our pockets. Mobilecommunication studies have not been limited to voice communication, but it provided theneeded mobile data transmission. Thanks to this improvement the needs which used to be metby traditional means have started to be met with mobile devices. The most important serviceprovided is the mobile internet service. Mobile internet is a technology that includes servicesvarying from shopping to corporate networks. This technology is added to our mobile deviceswith GPRS and EDGE technologies which work over GSM system. There are operators in theworld which provide the same service by using the third generation GSM systems; however,only trial studies have been going on in Turkey.The work in this study is the security issues of the GPRS system which is very commonlyused by the GSM operators to provide mobile internet service. The information needed to beprotected, the potential attackers, and the security threats of the GPRS system are presented.Security countermeasures are developed in order to be protected against the threats.Moreover, criteria needed by the GPRS operators to provide a secure service are determined,and they are tested on a live GPRS network. In order to develop these tests, a sample GPRSnetwork has been constructed and the security tests have been repeated. For this sample GPRStest system, a security policy which can also be used by GPRS operators has been developed.Key Words: Mobile internet, GSM, GPRS, Security, (A3, GPRS-A5, A8) Authentication andciphering algorithms, security policy, EDG