For a long time I’ve been interested in the lovely and exciting art of Reverse Code Engineering (RCE) and on more than one occasion I’ve been sucked in to spending hours and hours delving through pages of ASM code searching for the answer.
Today is no different. With Amy feeling pretty crook due to a nasty headache, I thought I’d retire to my PC and do something quiet that I haven’t done for ages. So I downloaded a crackme from Crackmes.de and started reversing. After nailing the problem to the wall, I decided to unleash my learnings on the world via a tutorial. When coders go through the rigmarole of producing these little apps for people like me to play with, it seems only fair that I give back with a bit of information on how I broke their protection scheme. Not just that, but it gives other wannabe-reversers something to read and learn from to.
For those of you who are interested in reading and learning the basics, feel free to download the goods. Any feedback is appreciated (but only if it’s good 
).
March 6, 2007
This sentance on page 5 seems to be incomplete:
“This bit of code just makes sure that both the username (the length of which is stored in EDI) and the serial (the length of which is stored in EAX).”
I assume it’s meant to be:
“This bit of code just makes sure that both the username (the length of which is stored in EDI) and the serial (the length of which is stored in EAX) are at least 6 characters long.”?
March 7, 2007
Right you are Gav. Thanks for that. I have fixed it up