ABSTRACT
The convergence of a wireless communication infrastructure, mobile computing devices, and embedded systems is causing a profound shift in the way we live and work, offering the promise of bringing us closer to the Holy Grail of information technology: ubiquitous computing (computing at any place and at any time) [3]. To fulfill the promise of ubiquitous computing, information about mobile users’ locations is a critical and valuable resource that has to be utilized. Many efforts have been directed toward making such information available as a key service in the ubiquitous computing environment. The location information service or functionality can act as a double-edged sword, however, as it can make our life more convenient while providing criminals with powerful weapons to compromise the privacy of mobile users. Computer scientists have realized that, unless the use of this information is strictly controlled, it can be applied to a variety of unsavory situations [3,4].
