Tips and instructions for beginners

Tips and instructions for beginners

Tips and instructions for beginners

Common Assembly commands for software cracking

Cmp a, B // compare A and B
MoV A, B // send the value of B to the value of a, so that a = B
RET // return the main program
NOP // no effect, abbreviated as "do nothing" (machine code 90)
(Ultraedit open and edit the EXE file to see the NOP of 90 equivalent Assembly statements)
Call // call a subroutine ending with RET
Je or JZ // equal jump (machine code 74 or 84)
JNE or jnz // skip if not equal (machine code is 75 or 85)
JMP // unconditional jump (machine code is EB)
JB // skip if the value is smaller
Ja // skip if the value is greater
JG // skip if the value is greater
Jge // skip if the value is greater than or equal
Jl // skip if the value is smaller
Pop XXX // XXX output Stack
Push XXX // XXX pressure Stack

Brute force cracking

One (HOP) will die, and nine (90) will be Hu
(Corresponding to 2 above -- changed to NOP)
One (HOP), one (EB)
(Corresponding to the above 1 -- modified to JMP)
(74) Change (75)
(84) Change (85)
It doesn't matter if you don't understand it. Remember it first and understand it later.