Nope, as long there is _any_ proof (i.e. implementation logic), you can use it. Similar to software -- if you're happy with a library's interface, you don't hav

Nope, as long there is _any_ proof (i.e. implementation logic), you can use it. Similar to software -- if you're happy with a library's interface, you don't have to read its source code in order to use it.