To worry about piracy, you must first have a product that will be a certain hit. So, I wonder why asking such a question? Can you please explain it? We might probably be able to help you out on that, but as it is, it is too broad as a topic.
By the way, AAA companies do their best to create anti piracy methods, and games, in the end, get cracked. So here comes the second question. Do you believe you can fight this with a free solution?
What a developer should be thinking, is not creating a good anti piracy countermeasure, but a good game. If you got a good game, you will succeed. If you got a crappy game with great DRM, it's obvious that nobody will buy it. Which scenario is better?