Just a note of caution that if it exists in a drawing it can be copied. For example, with deter I think there is a LISP undeter out there, sounds familiar anyway, if you know what was used to protect the file.
I am guessing - though might be wrong - that you want to protect your work and information but need to send your clients a dwg... but don't want them to copy it? If the clients don't specify dwgs then you could send them raster PDFs (up to date AutoCAD will produce vector PDFs by default). You could protect the drawing contractually but once copied the information is out there to use though.
It isn't anything I have ever had to do though, current work if the client pays for DWGs, that is what they get otherwise PDFs, but end of the day they pay so they can have them. Before working for an owner we had control of all the drawings, never went out the office. Never worked for a manufacturer but looking at manufacturers drawings they often only include the important information such as an overall dimension, connection points or whatever.
There was this link here which goes through protecting PDFs a little, maybe some of these ideas might help: