Open safe, insert dvd into safe, lock safe. This is the easiest method.
If you are asking how to copy protect your dvd, and keep other people from making copies after you give or sell it to them, you can't. There are too many ways that encryption can be broken or bypassed, and none of the commercial programs that are designed to protect dvds work very well to stop this. Paradoxically, even though ineffective, the commercial programs are also very expensive and beyond the means of most home users.