[CodeEngn.com] Advance RCE Level 16

Mission...
Generate the key file to print out "registered: true".
Post the key file in a private thread in the message board to have it verified.
(Difficulty : ★★★☆☆)


Analysis...

Solution and Coding...
Reverse2L16.cpp
Copyright (C) 2011 3735943886

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.

Private Access Only...

Result...

Omake...
This attachment is C++ dump of Advance RCE level 16.
Please feel free to download and test it.

Reverse2L16_dumped.exe

(Compiled with GCC)

//
// Reverse2L16_dumped.cpp
// C++ dump of Advance RCE L16 (CodeEngn.com)
// Made by 3735943886
// License : GPL
//

#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;

void CreateTemplate(void *lpOutBuffer, const void *lpInBuffer)
{
  // Direct Conversion of ASM (00405340)

  unsigned long *lpResult;
  unsigned char *lpBufferPointer;
  unsigned int i;
  unsigned int v8;

  lpResult = (unsigned long *)lpOutBuffer;
  lpBufferPointer = (unsigned char *)lpInBuffer;

  for(i = 0; i < 0x10000; i += 0x100)
  {
    v8 = i + *lpBufferPointer;
    lpResult[v8 >> 5] |= 1 << (v8 & 0x1F);
    lpBufferPointer++;
  }
  return;
}

bool TestBuffer(void *lpBuffer)
{
  //Direct Conversion of ASM (004053F0)

  unsigned int Var1, Var2;
  int Flag1, Flag2;
  unsigned int i, j;

  Var1 = 0;
  for(i = 0; i < 0x100; i++)
  {
    Flag1 = 0;
    Flag2 = 0;
    Var1 = i;
    Var2 = i * 0x100;                              // Increased Var2 by 0x100, whereas Increased Var1 by 1
    for(j = 0; j < 0x100; j++)
    {
      // Test Var2 - 0 to 0xFF, 0x100 to 0x1FF, 0x300 to 0x3FF ...    -> only 1 must be set among 0x100 tests
      // Test Var1 - 0 to 0xFF00, 1 to 0xFF01, 2 to 0xFF02 ...      -> only 1 must be set among 0x100 tests
      // Horizontal and Vertical line
      Flag2 += ((1 << (Var2 & 0x1F)) & ((unsigned long *)lpBuffer)[Var2 >> 5]) != 0;
      Flag1 += ((1 << (Var1 & 0x1F)) & ((unsigned long *)lpBuffer)[Var1 >> 5]) != 0;
      Var2++;                                  // Increased Var2 by 1
      Var1 += 0x100;                            // Increased Var1 by 0x100
    }
    if (Flag2 != 1 || Flag1 != 1)                      // Both variables must be 1 = Only 1 on each H and V line
      return 0;
  }
  return 1;
}

bool TestBuffer2(void *lpBuffer)
{
  //Direct Conversion of ASM (004054B0)

  int Code1[] = {-1, -1, 1, 1};    // 00412108
  int Code2[] = {-1, 1, -1, 1};    // 00412118

  unsigned int Var1;
  unsigned int Var2;

  int Flag;
  unsigned int i, j, k;

  for(i = 0; i < 0x100; i++)
  {
    for(j = 0; j < 0x100; j++)
    {
      for(k = 0; k < 4; k ++)
      {
        Var2 = i;
        Var1 = j;
        Flag = 0;
        while((int)Var1 >= 0 && Var1 < 0x100 && (int)Var2 >= 0 && Var2 < 0x100)
        {
          // 4 Patterns but can catogarized into 2 patterns (diagonal line)
          // 0x0000, 0x0101, 0x0202, 0x0303, ... 0xFFFF - Positive Slope
          // 0x0100, 0x0201, 0x0302, 0x0403, ... 0xFFFE  - Positive Slope
          // 0x8000, 0x8101, 0x8202, 0x8303, ... 0xFF80 - Negative Slope
          // 0xFF00, 0xFE01, 0xFD02, 0xFC03, ... 0x00FF - Negative Slope
          Flag += ((1 << (Var1 & 0x1F)) & (((unsigned long *)lpBuffer)[(Var1 + Var2 * 0x100) >> 5])) != 0;
          Var1 += Code1[k];
          Var2 += Code2[k];
        }
        if(Flag > 1)
          return 0;
      }
    }
  }
  return 1;
}

int main()
{
  const char *FileName = "./crackme.key";
  const size_t FileSize = 0x100;

  fstream fKeyFile;
  char *Buffer;
  unsigned long *Buffer2;

  Buffer = new char [FileSize];
  Buffer2 = new unsigned long [FileSize * 8];

  cout << endl << "Reverse2L16_dumped.cpp" << endl
    << "C++ dump of Advance RCE L16 (CodeEngn.com)" << endl
    << "Made by 3735943886" << endl << "License : GPL" << endl << endl;

  fKeyFile.open(FileName, ios::in | ios::binary);
  if(fKeyFile.is_open())
  {
    fKeyFile.seekg(0, ios::end);
    if(FileSize == fKeyFile.tellg())
    {
      fKeyFile.seekg(0, ios::beg);
      fKeyFile.read(Buffer, FileSize);

      memset(Buffer2, 0, FileSize * 8);
      CreateTemplate(Buffer2, Buffer);
      if(TestBuffer(Buffer2) && TestBuffer2(Buffer2))
      {
        cout << "registered: true" << endl;
        delete [] Buffer;
        delete [] Buffer2;
        fKeyFile.close();
        return 1;
      }
    }
  }

  cout << "registered: false" << endl;
  delete [] Buffer;
  delete [] Buffer2;
  fKeyFile.close();
  return 0;
}