签到 xor

main函数

int __cdecl main_0(int argc, const char **argv, const char **envp)
{
  char v4; // [esp+0h] [ebp-FCh]
  char v5; // [esp+0h] [ebp-FCh]
  char v6; // [esp+0h] [ebp-FCh]
  char v7; // [esp+0h] [ebp-FCh]
  char v8; // [esp+0h] [ebp-FCh]
  char v9; // [esp+0h] [ebp-FCh]
  char v10; // [esp+0h] [ebp-FCh]
  char v11; // [esp+0h] [ebp-FCh]
  char v12; // [esp+0h] [ebp-FCh]
  char v13; // [esp+0h] [ebp-FCh]
  char v14; // [esp+0h] [ebp-FCh]
  char v15; // [esp+0h] [ebp-FCh]
  char v16; // [esp+0h] [ebp-FCh]
  char v17; // [esp+0h] [ebp-FCh]
  char v18; // [esp+0h] [ebp-FCh]
  char v19; // [esp+0h] [ebp-FCh]
  char v20; // [esp+0h] [ebp-FCh]
  char v21; // [esp+0h] [ebp-FCh]
  char v22; // [esp+0h] [ebp-FCh]
  char v23; // [esp+0h] [ebp-FCh]
  int i; // [esp+DCh] [ebp-20h]
  unsigned int v25; // [esp+F4h] [ebp-8h] BYREF

  sub_45A7BE((int)&unk_50B110, v4);
  sub_45A7BE((int)&unk_50B158, v5);
  sub_45A7BE((int)&unk_50B1A0, v6);
  sub_45A7BE((int)&unk_50B1E8, v7);
  sub_45A7BE((int)&unk_50B230, v8);
  sub_45A7BE((int)&unk_50B278, v9);
  sub_45A7BE((int)&unk_50B2C0, v10);
  sub_45A7BE((int)&unk_50B308, v11);
  sub_45A7BE((int)&unk_50AFD0, v12);
  sub_45A7BE((int)"|              by 0x61                                 |\n", v13);
  sub_45A7BE((int)"|                                                      |\n", v14);
  sub_45A7BE((int)"|------------------------------------------------------|\n", v15);
  sub_45A7BE(
    (int)"Play a game\n"
         "The n is the serial number of the lamp,and m is the state of the lamp\n"
         "If m of the Nth lamp is 1,it's on ,if not it's off\n"
         "At first all the lights were closed\n",
    v16);
  sub_45A7BE((int)"Now you can input n to change its state\n", v17);
  sub_45A7BE(
    (int)"But you should pay attention to one thing,if you change the state of the Nth lamp,the state of (N-1)th and (N+1"
         ")th will be changed too\n",
    v18);
  sub_45A7BE((int)"When all lamps are on,flag will appear\n", v19);
  sub_45A7BE((int)"Now,input n \n", v20);
  while ( 1 )
  {
    do
    {
      while ( 1 )
      {
        sub_45A7BE((int)"input n,n(1-8)\n", v21);
        sub_459418();
        sub_45A7BE((int)"n=", v22);
        sub_4596D4("%d", &v25);
        sub_45A7BE((int)"\n", v23);
        if ( v25 <= 8 )
          break;
        sub_45A7BE((int)"sorry,n error,try again\n", v21);
      }
      if ( v25 )
      {
        sub_4576D6(v25 - 1);
      }
      else
      {
        for ( i = 0; i < 8; ++i )
        {
          if ( (unsigned int)i >= 9 )
            j____report_rangecheckfailure();
          byte_532E28[i] = 0;
        }
      }
      j__system("CLS");
      sub_458054();
    }
    while ( byte_532E28[0] != 1
         || byte_532E29 != 1
         || unk_532E2A != 1
         || unk_532E2B != 1
         || unk_532E2C != 1
         || unk_532E2D != 1
         || unk_532E2E != 1
         || unk_532E2F != 1 );
    sub_457AB4();
  }
}

能看出来啥都没有 只有游戏框架 我们搜索字符串来定位 flag

定位到

int sub_45E940()
{
  int i; // [esp+D0h] [ebp-94h]
  _BYTE v2[3]; // [esp+DCh] [ebp-88h] BYREF
  _BYTE v3[19]; // [esp+DFh] [ebp-85h] BYREF
  _BYTE v4[32]; // [esp+F2h] [ebp-72h] BYREF
  char v5[14]; // [esp+112h] [ebp-52h] BYREF
  _BYTE v6[64]; // [esp+120h] [ebp-44h]

  sub_45A7BE("done!!! the flag is ");
  v6[0] = 18;
  v6[1] = 64;
  v6[2] = 98;
  v6[3] = 5;
  v6[4] = 2;
  v6[5] = 4;
  v6[6] = 6;
  v6[7] = 3;
  v6[8] = 6;
  v6[9] = 48;
  v6[10] = 49;
  v6[11] = 65;
  v6[12] = 32;
  v6[13] = 12;
  v6[14] = 48;
  v6[15] = 65;
  v6[16] = 31;
  v6[17] = 78;
  v6[18] = 62;
  v6[19] = 32;
  v6[20] = 49;
  v6[21] = 32;
  v6[22] = 1;
  v6[23] = 57;
  v6[24] = 96;
  v6[25] = 3;
  v6[26] = 21;
  v6[27] = 9;
  v6[28] = 4;
  v6[29] = 62;
  v6[30] = 3;
  v6[31] = 5;
  v6[32] = 4;
  v6[33] = 1;
  v6[34] = 2;
  v6[35] = 3;
  v6[36] = 44;
  v6[37] = 65;
  v6[38] = 78;
  v6[39] = 32;
  v6[40] = 16;
  v6[41] = 97;
  v6[42] = 54;
  v6[43] = 16;
  v6[44] = 44;
  v6[45] = 52;
  v6[46] = 32;
  v6[47] = 64;
  v6[48] = 89;
  v6[49] = 45;
  v6[50] = 32;
  v6[51] = 65;
  v6[52] = 15;
  v6[53] = 34;
  v6[54] = 18;
  v6[55] = 16;
  v6[56] = 0;
  qmemcpy(v2, "{ ", 2);
  v2[2] = 18;
  qmemcpy(v3, "bwlA)|P}&|oJ1Sl^lT", 18);
  v3[18] = 6;
  qmemcpy(v4, "`S,yhn _uec{", 12);
  v4[12] = 127;
  v4[13] = 119;
  v4[14] = 96;
  v4[15] = 48;
  v4[16] = 107;
  v4[17] = 71;
  v4[18] = 92;
  v4[19] = 29;
  v4[20] = 81;
  v4[21] = 107;
  v4[22] = 90;
  v4[23] = 85;
  v4[24] = 64;
  v4[25] = 12;
  v4[26] = 43;
  v4[27] = 76;
  v4[28] = 86;
  v4[29] = 13;
  v4[30] = 114;
  v4[31] = 1;
  strcpy(v5, "u~");
  for ( i = 0; i < 56; ++i )
  {
    v2[i] ^= v6[i];
    v2[i] ^= 0x13u;
  }
  return sub_45A7BE("%s\n");
}

能看到只有一个简单的xor和拼接

exp

key = [
    18, 64, 98, 5, 2, 4, 6, 3, 6, 48, 49, 65, 32, 12,
    48, 65, 31, 78, 62, 32, 49, 32, 1, 57, 96, 3, 21, 9,
    4, 62, 3, 5, 4, 1, 2, 3, 44, 65, 78, 32, 16, 97, 54,
    16, 44, 52, 32, 64, 89, 45, 32, 65, 15, 34, 18, 16
]

encrypted = (
    b"{ " + bytes([18]) +
    b"bwlA)|P}&|oJ1Sl^lT" + bytes([6]) +
    b"`S,yhn _uec{" +
    bytes([
        127, 119, 96, 48, 107, 71, 92, 29, 81, 107,
        90, 85, 64, 12, 43, 76, 86, 13, 114, 1
    ]) +
    b"u~"
)

flag = bytes(c ^ k ^ 0x13 for c, k in zip(encrypted, key))
print(flag.decode())

flag

zsctf{T9is_tOpic_1s_v5ry_int7resting_b6t_others_are_n0t}

一把梭

image