Nice one, David! I appreciate your thoroughness, and I will go over your steps because I have learned more about Mathematica from Mathematica discussion boards than anywhere else; and you've touched on interesting things that could be used in a consulting project. But as for incorporating these steps into the creation of encrypted university material, it is far too much pain in its complexity and the time it takes away from the real business of teaching and research. Hope Wolfram catches up to the game on this issue. Point-and-click encryption for PDFs is built right into Preview on Macs. I can do the same in RAD environments like LiveCode in a minute or two. As a matter of fact, I've been wondering whether it would be better, for some teaching applications, to export my Mathematica functions to C (that, I think I could learn to do) and then use them as externals in encrypted apps that I build with LiveCode.
Gregory