Klaus Vedder

Security Aspects of Mobile Communications

Security requirements and services of a mobile communication system differ, due to the radio communication between the user and the base station, extensively from those of a fixed network. There is no physical link in the form of a (fixed) telephone line between the user and the local exchange, which could serve to “identify” the user for routing and charging purposes. His identity has to be verified over an air interface. Authentication by means of cryptographic procedures is thus required to stop impostors from taking on the identity of somebody else and “transferring” calls and charges. Eavesdropping on the radio path and intercepting a conversation or data or tracing the whereabouts of a user by listening to signalling data are other serious threats. This paper discusses the countermeasures designed into one of the most advanced radio networks, the Global System for Mobile Communications, as well as some security aspects of the network management related to these measures. Some of the differences between this system and the planned Digital European Cordless Telephone system are highlighted.