ventilator: "it depends a bit on how well the key [..] are hidden in the exe."

Actually that is the real main point. My encryption methods are extremly safe (theoretically not crackable). But: The key is always in the exe file. Of course you can encrypt it, but that you would need an encryption code for the key ==> again unsafe. And even if you would encrypt your key 10 times, the hacker / cracker would just attack the if(key == correct) point.. therefore i'm ruining my brain in a search for a better / more safe method.

Greetings,
Timo