運が悪かったので、効果を元に戻そうとしたコード関数があります。私が持っている元の機能は次のとおりです。
ror al,1 // rotates the al part of the eax register (the Ekey) bitwise by 1 bit, as 1 mod 8 = 1 (al = 2D)
ror al,1 // moves the rightmost bit from al (the end of the Ekey) and shifts everything along
ror al,1 // rotates al bitwise by 1 bit, as 1 mod 8 = 1 (al = 4B)
ror al,1 // rotates the end 8 bits of the Ekey bitwise by 1 bit, as 1 mod 8 = 1 (al = A5)
push ecx // preserves the value of the encrypted character by pushing it on the stack, the stack pointer decrements by 4 to allow this
not eax // completes the ones' complement on the Ekey, toggling the bits
mov edx,eax // copies the current value of the Ekey register and places it in edx, for holding
pop eax // restores original register value from stack
xor eax,edx // completes a bitwise exclusive or on the Ekey, with the previous value of the Ekey that was stored in edx
ror al,1 // rotates the last 8 bits of the Ekey bitwise by 1 bit, as 1 mod 8 = 1
ror al,1 // rotates al bitwise by 1 bit, as 1 mod 8 = 1
not eax // completes the ones' complement on the Ekey value, 'flipping' eax entirely
add eax,0x20 // adds the hex value of 20 (32 in base 10) to the current value in the Ekey
特定の行ごとではなく、上記のコードの効果のみを元に戻す必要があります。私はさまざまなことを試しました...試行1(これは間違っています):
sub eax, 0x20
not eax
rol al, 2
xor ecx, eax
push eax
mov eax, edx
not eax
pop ecx
rol al, 4
私の2番目の試みは以下の通りです:
sub eax, 0x20
not eax
rol al, 2
not eax
xor ecx, eax
これの何が問題なのですか... xor の効果を元に戻すことはできますか?