Comparing algorithm

I'm working on a program that basically compares strings to find similarities in the way the have been generated, and so it finds the encryption key. More are the strings, better are the results...basically, with this you can create any keygen ( not only for piracy, but also for testing serial code algorithms )...It's simply to do I know, but I want to optimize the code to have more accuracy in the results. I wrote a bit of it in C ( the final version will be wrote in Python ) but I'll post it later, because it's too buggy for now and also I need suggestion about optimizing the algorithm...any idea about improving the speed? I use recursive functions and for cycles for doing the comparitions, and for now a bit of inline assembly for memory handling.
I'm also working with a different version of the program to decode tripcodes, or at least for finding the key to decode them all....I know their algorithm is very weak and they are already been decoded, but I want to do something better decoding also secure tripcodes. Ideas?

inputting as many 5's as the installer will allow you to actually works for more things than you'd expect.
i lol'd muchly when i tried that and it worked for visual studio 4 (which i obtained legally but then lost the cd key for) several years ago.