Reverse To Make A Keygen

This is a old keygenme but is a good learning curve.  Coded by KiTo
Keygen Download Zippyshare
Tools::
x32dbg.exe

We see there is a user and serial this time.
If we click Check without entering nothing we get this message:

This time we can use a different approach by finding this string to do this while the program is running and we at the entry point: press this to fetch the strings.

We can now see the address for the messages.
From the entrypoint 0x00401000 press G and the graph will show you the flow of the program.

Moving in the graph you can see where the jump is when we don't enter anything.

We could just patch this to go to good boy message but that's super easy.
Just before this message it compares input is 3 if it's greater we don't get this message, so working with a 4 or more username length we can move to the main part.

After all this will decide if we get Good Boy message or Bad Boy message.
Lets look at this function :

This function moves whats at address esp+ecx+8 into EDX 0x30 = 0, EDX is then added to EDI , Increments ECX[char counter] finaly compared with EAX[char length].
After its cycled 4 times EDI = 0x0C.

This is the last function EDI x 0x539[1337] = 256704.

My Keygen written in C code.

And there is the keygen Enjoy.