I am working on a project where we have to put the classification (unclassified, etc) in the viewer somehow. What we are currently doing is using the czml-writer project to generate CZML files. Is there a way that I can use the czml-writer project to put a label at the top and bottom of the cesium widget that would indicate the viewers classification?
Cesium is ultimately just an HTML canvas. You can put any arbitrary HTML on top. Just insert a div at the top of the Cesium container with the banner you need.