2020河北省赛线下CTF：re1

河北省赛线下CTF：re1"/>

2020河北省赛线下CTF：re1

一种利用返回地址来提供对比字符的新出题方式

flag里的每一个值都对应一个函数，函数输出一个字符同时将输入的flag的每个值与其他两个值异或，返回值是下一个地址，利用地址跳转来最后组成congratulate_you，这样结果也有了，算法也有了，逆向写出爆破脚本。

for i in range(128):if 0x401100 ^ i ^ 0x95 == 0x4011C0: # 0print(chr(i),end='')
for i in range(128):if 0x401200 ^ i ^ 0x8F == 0x4012D0: # 1print(chr(i),end='')
for i in range(128):if 0x401500 ^ i ^ 0x42 == 0x401510: # 2print(chr(i),end='')
for i in range(128):if 0x401400 ^ i ^ 0xF == 0x401450: # 3print(chr(i),end='')
for i in range(128):if 0x401300 ^ i ^ 0xA3 == 0x401390: # 4print(chr(i),end='')
for i in range(128):if 0x401100 ^ i ^ 0x78 == 0x401100: # 5print(chr(i),end='')for i in range(128):if 0x401000 ^ i ^ 0xc3 == 0x4010A0: # 6print(chr(i),end='')
for i in range(128):if (0x4012FC + 4) ^ i ^ 0x55 == 0x401330: # 7print(chr(i),end='')
for i in range(128):if 0x401100 ^ i ^ 0x51 == 0x401160: # 8print(chr(i),end='')
for i in range(128):if 0x401200 ^ i ^ 0x4c == 0x401220: # 9print(chr(i),end='')
for i in range(128):if 0x401500 ^ i ^ 0x43 == 0x401570: # 10print(chr(i),end='')
for i in range(128):if 0x401300 ^ i ^ 0x9e == 0x4013F0: # 11print(chr(i),end='')
for i in range(128):if 0x401200 ^ i ^ 0xb7 == 0x401280: # 12print(chr(i),end='')
#U_R_3xce1l3n7