[rkangel]

Security through obscurity is when obscurity is your only security measure. When used on top of an otherwise secure system, obscurity actually makes finding vulnerabilities harder.

The principle with open source is that you can trade that obscurity away in favour of the "many eyes" on your code and the fact that it is then proven secure. That tradeoff is definitely worth it, but that doesn't mean that the obscurity doesn't help security.