Deters, Ralph2013-01-032013-01-032012-092012-10-31Septemberhttp://hdl.handle.net/10388/ETD-2012-09-705As of 2011, there were about 5,981 million mobile devices in the world [1] and there are 113.9 million mobile web users in 2012 [2]. With the popularity of web services for mobile devices, the concern of security for mobile devices has been brought up. Furthermore, with more and more cooperation of organizations, web services are now normally involved with more than one organization. How to trust coming requests from other organizations is an issue. This research focuses on building a trust model for the web services of mobile devices. It resolves the issues caused by mobile devices being stolen, lost, users abusing privileges, and cross-domain’s access control. The trust model is distributed in each node of the web servers. The trust value is calculated for every incoming request to decide whether the request should be served or not. The goals of the trust model are 1) flexible; 2) scalable; 3) lightweight. The implementation is designed and accomplished with the goals in mind. The experiments evaluate the overhead for the trust module and maximum capacity of the system.engtrust modelweb servicesmobile devicescontexttext