I recall that Sonic's DVDitPE does have copy protection encryption capability for you writable project authoring.

BTW - GREAT dvd creation software. My older version does not include encryption but the newer versions do it well.

PROBLEM is you not being able to use consumer copy programs to make multiple copies.

For a few copies, no problem, just tell DVDitPE how many copies you want and it will make them at time of dvd program creation. Or course, if you really want mass production just have a pro duplication shop do the job. Whacky for an individual to try to make hundreds of distribution copies.
goodluck