Crackability of a software

Originally Posted by Syoma

I think it is just trash topic. Read manuals first. Start from NP-hard problems.

-.-'

I repeat it for the last time: my statement doesn't refer to protections that involve, in any way, tecniques of encryption when the key is not included or deducible from the code of the exe...

In particullary, my question is referred to the existence of some tecniques or protection software (such as themida or armadillo) that doesn't allow, in any way, to do an operation of reversing engineering (or cracking if is the case)