A prototype for Trusted X labeling policies

The Trusted X Window System (TX/WS) is a prototype of the X Window System for the TMach (Trusted Mach) operating system. TX/WS is designed to support users manipulating information of different sensitivity labels simultaneously. In TX/WS, each top-level window on the screen may belong to a different application. These applications may be running at a variety of sensitivity labels. Each window is visibly labeled with the maximum sensitivity label of the application which created the window. To assist the user of a multi-level windowing system with overlapping windows, a visible labeling policy is required to avoid inadvertent misclassification of information. This paper describes a prototype which demonstrates various labeling policies for overlapping windows. It also summarizes feedback from the prototype