Lesson 3 :: Cracking ... The Begin of the Quest

In lesson 1 and 2 we had some really tough words but we had also a brief intro to the underground world .jump command (i mentonned briefly last time in that book) is essential for every cracker to know :JA :jump if aboveexample
Code:eax = 20d (i believe you know that "d" stands for decimal)
edx = 10d
cmp eax,edx
JA good_bye (if eax is greater edx it goes to goodbye)
jmp elsewhere (else it goes elsewhere)JAE jump if above or equal JNAE jump if not above or equalJB Jump if Belowexample
Code:eax = 30d
edx = 20d
cmp eax,edx
JB good_bye (if eax is below edx it goes to goodbye)
jmp elsewhere (else it goes elsewhere)the rest is automatic always tests on two registres and then a jump to section of the codeJNB jump if not belowJBE jump if not below or equalJNBE jump if not below or equalJC Jump on CarryJNC do not Jump on CarryJE jump if equal JNE jump if not equalJG jump if greater JNG jump if not greaterJGE jump if greater or equal JNGE jump if not greater or equalJL jump if lowerJNL jump if lowerJLE jump if lower or equalJNLE jump if not lower or equalJO Jump on OverflowJNO Jump on No OverflowJS Jump on Sign (Negative)JNS Jump on Sign (Positive)JZ Jump if Zero (same as JE)JNZ Jump if not Zero (same as JNE)next lesson we will get deaper with another command but i belive talking too much is useless so i prefer posting tutorials either video one or with pictures so that you can see what we're talking about and i prefer working for now on crackme wich are software for studies purposes .for those who has not yet the softwares get the cracking kit of drmechove :

Code:

http://rapidshare.com/files/130900205/cracking_kit.zip