JustRe

第一部分：

兩端執行相同操作，看其中一個即可。

from z3 import *

base_data = [0x78B09135,0xE78DBAE5,0xFB0C084A, 0x3B5C0EA2,0x82C7F904,0xF937EE81,0xEB130A06,0x3B4D7202,0x3ACC6A08,0x045A0A49, 0x26E84E1B,0x5513B95C, 0x3B4D8209,0xAD132C0D,  0x044BEE4A,0x61164B1F]

base_data = [0x79B19266,  0x0E88EBBB6,  0x0FC0D093B, 0x3C5D0F73,  0x83C8FA15,      0x0FA38EF92,  0x0EC140B17, 0x3C4E7313, 0x3BCD6B19,  0x55B0B5A,0x27E94F0C,0x5614BA4D,0x3C4E831A,0x0AE142D1E, 0x54CEF5B,    0x62174C10]

func_data = [0x83EC8B55,0xEC81F0E4,0x00000278,0x405004A1,0x89C43300,0x02742484,0x100F0000,0x4041A805,0x41C0A000,0x0F560040,0x2C244411,0x7E0FF357,0x4041B805,0xD60F6600,0x0F402444,0x6A0A4110]


f1 = BitVec('f1', 4*8)
f2 = BitVec('f2', 4*8)

# f1 = Int("f1")
# f2 = Int("f2")

solver = Solver()

for i in range(16):

    solver.add(func_data[i] == ((f1 + i) ^ ((0x1010101 * f2) + base_data[i])))   

s = solver.check()
m = solver.model()

print hex(int(str(m[f1])))[2:], hex(int(str(m[f2])))[2:]

# 13242218 18

第二部分 密鑰為 “AFSAFCEDYCXCXACNDFKDCQXC” 的3des算法。直接算即可

from Crypto.Cipher import DES3
import base64

BS = DES3.block_size


def pad(s):
    return s + (BS - len(s) % BS) * chr(BS - len(s) % BS)


def unpad(s):
    return s[0:-ord(s[-1])]


class prpcrypt():
    def __init__(self, key):
        self.key = key
        self.mode = DES3.MODE_ECB

    def encrypt(self, text):
        text = pad(text)
        cryptor = DES3.new(self.key, self.mode)
        x = len(text) % 8
        if x != 0:
            text = text + '\0' * (8 - x)
        # print(text)
        self.ciphertext = cryptor.encrypt(text)
        return (self.ciphertext).encode("hex")

    def decrypt(self, text):
        cryptor = DES3.new(self.key, self.mode)
        # de_text = base64.standard_b64decode(text)
        plain_text = cryptor.decrypt(text)
        st = str(plain_text.decode("utf-8")).rstrip('\0')
        print st.encode("hex")
        print st
        out = unpad(st)
        return out

# 507CA9E68709CEFA20D50DCF90BB976C  #9090F6B07BA6A4E8

cipher = "507CA9E68709CEFA20D50DCF90BB976C".decode("hex")

p = prpcrypt("AFSAFCEDYCXCXACNDFKDCQXC")

print p.decrypt(cipher)