There's lots of them out there. Lots of different types.
Most popular protection sports here in the US at the moment:
Schutzhund (IPO) - 3 phase sport. Tracking, Obedience, Protection. United Schutzhund Clubs of America ? Schutzhund Training
Protection Sports Association (PSA) - Obedience and controlled protection work. Basically a civilian protection dog.
About PSA K9 | PSA K9
and of course the wonderful Wiki to list some of the others:
List of protection sports - Wikipedia, the free encyclopedia
To answer your question: For all of the those listed above- Lots and lots of professional training with the right dog (proper temperament, nerves, and drives). Obedience must be solid and remain top of the list for importance.
Have fun with your research!