首先看解密后一段代码:
00401115 . 6A 00 push 0
00401117 . 68 78514000 push 00405178 ; ASCII “You did it”
0040111C . 68 38514000 push 00405138 ; ASCII “Correct Serial ;)”,LF,LF,”Now write a Tutorial how you solved it :)”
00401121 ? 53 push ebx
00401122 ? FFD6 call esi
这段代码解密前是:
00401115 . EE out dx, al
00401116 . 12EC adc ch, ah
00401118 . 6A D5 push -2B
0040111A . 52 push edx
0040111B . 847A BC test byte ptr [edx-44], bh
0040111E . 43 inc ebx
0040111F . C412 les edx, fword ptr [edx]
00401121 . D7 xlat byte ptr [ebx+al]
00401122 . ED in eax, dx
00401123 . 52 push edx
00401124 . 821482 14 adc byte ptr [edx+eax*4], 14
00401128 . 8290 90909090>adc byte ptr [eax+90909090], -70
新意在于用输入的Key做运算得出的值作为解密钥匙~
还是第一次碰到这种CM 但是比不上之前的XOR EDX EDX 的点睛之笔!
一组Key:
EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEDDDDDDDDDDDDDDDDDDDD