So what I need to do is find some way to prevent people from figuring out the links, or to make it so that linking directly to the file doesn't work. While I don't think it's particularly likely that people who have been given password access are going to just send people direct links to these files right and left, I have to build the page assuming that sooner or later, due to malice or stupidity, they will.
So ... any suggestions?
IMPORTANT NOTE: I am not allowed to use Javascript.
-The Gneech