First things first: What do you bring to the table, besides having an idea? Inside experience in your target industry? Industry contacts? Venture capital? If y

First things first: What do you bring to the table, besides having an idea? Inside experience in your target industry? Industry contacts? Venture capital? If you bring any of the above, it's a non-issue. If your hacker runs off with your idea and tries to compete with you, he/she will go down in flames. If you don't bring any of the above: Seriously stop and evaluate whether or not your "big idea" is actually worth pursuing in the first place. Ideas that don't come from years of experiencing an industry's pain points from the inside tend to be very risky propositions. (This includes about 100% of consumer-oriented software businesses.) In this case, your best bet might be to give up on finding a co-founder, and find a contractor that you just pay up front. People are a lot more willing to sign non-disclosure agreements when you're waving cash under their noses, which in turn resolves your fears of them stealing your idea.