I moved your post to the InDesign and Illustrator forums.
None of these file types can be locked.
Locked files, like PDFs with a password, cannot be printed for RIP.
As far as I know there's nothing you can do to prevent this kind of theft beyond dealing only with service providers you know and can trust.
And it's a whole lot easier to sue someone local for copyright infringement than it is to sue someone overseas if you get burned. Folks who steal your work count on that.
Just found out that there is are a few additional app/software can be used on any files to make it self destruct. Droplr and Quick Crypt
Thank you for advice