The Universal Mobile Telecommunications System (UMTS) is one of the new 'third-generation' mobile cellular communication systems. UMTS builds on the success of the 'second-generation' Global System for Mobile (GSM) system. One of the factors in the success of GSM has been its security features. New services introduced in UMTS require new security features to protect them. In addition, certain real and perceived shortcomings of GSM security need to be addressed in UMTS. This chapter surveys the major security features that are included in the first releases of the UMTS standards.

6.1 Introduction

The UMTS is one of the new 'third-generation' (3G) mobile cellular communication systems being developed within the framework defined by the ITU known as IMT-2000 [1]. UMTS builds on the capability of today's mobile technologies by providing increased capacity, data capability and a greater range of services using a new radio interface standard called UMTS Terrestrial Radio Access (UTRA) [2].

The basic radio, network and service parameters of the UMTS system were defined by the European Telecommunications Standards Institute (ETSI) in early 1998 [3]. ETSI developed the extremely successful second-generation GSM standard that is used by over 650 million customers world-wide and accounts for approximately 70 per cent of the wireless communications market [4]. An important characteristic of UMTS is that the new radio access network will be connected to an evolution of the GSM core network.

To help build on the global success of GSM, the UMTS standards...