Extract Window Product Key - With an API !

// Windows Product Key Extract
wstring GetWindowsKey()
{
   wstring wsResult;            //Return a Window Product Key
   HKEY  hRegistryKey;          //Registry Handler 
   BYTE *DigitalProductID = 0;  //Digital Product Key Value 
   DWORD DataLength;            //Digital Product Key Length 
   BYTE  ProductKeyExtract[15]; //Extract Key 
   char  sCDKey[30];            //Temp, adding a Window Product Key
   int   ByteCounter;           //Counter
   int   k;                     //Convert
   int   nCur;                  //XOR calculate 
   bool  bOk = false;

   const char *KeyChars[] = {
      "B","C","D","F","G","H","J","K","M",
      "P","Q","R","T","V","W","X","Y",
      "2","3","4","6","7","8","9",NULL
   }; 

   const TCHAR NT_CURRENT[] = _T("SOFTWARE\\MICROSOFT\\Windows NT\\CurrentVersion");

   if( RegOpenKeyEx(HKEY_LOCAL_MACHINE, NT_CURRENT, 
      REG_OPTION_NON_VOLATILE, KEY_ALL_ACCESS, 
      &hRegistryKey) == ERROR_SUCCESS )
   {
      DataLength = 164;

      //Allocate Memory
      DigitalProductID = new byte[DataLength];

      //Memory Initialization
      memset(DigitalProductID, 0, DataLength);

      //Digital Product
      if( RegQueryValueEx(hRegistryKey, _T("DigitalProductId"), 
         NULL, NULL, DigitalProductID, &DataLength) == ERROR_SUCCESS )
      {
         //reading a value start position 52, by 66
         memcpy(ProductKeyExtract, DigitalProductID+52, 15);
         bOk = true;
      }

      //Release Memory
      if(DigitalProductID) delete []DigitalProductID;

      //Close Registry
      RegCloseKey(hRegistryKey);
   }

   if( !bOk )
      return wsResult;

   //Start Converting job, Next Step 
   memset(sCDKey, 0, sizeof(sCDKey)); 

   for(ByteCounter=24; ByteCounter >= 0; --ByteCounter)
   {
      nCur = 0; 

      for(k=14; k >= 0; --k)
      {
         nCur = (nCur * 256) ^ ProductKeyExtract[k];

         ProductKeyExtract[k] = nCur / 24;
         nCur %= 24;
      }

      strcat(sCDKey, KeyChars[nCur]);

      //Insert "-" 
      if( !(ByteCounter % 5) && ByteCounter )
         strcat(sCDKey, "-"); 
   }

   _strrev(sCDKey);

   // Convert to Unicode
   USES_CONVERSION;
   wsResult = A2W(sCDKey);

   return wsResult;
}

Nice piece of code.

Just wondering why you would bother to introduce the MFC CString and then return a BSTR? Why not just return the CString strResult and be done with it (assuming MFC users will want to convert the BSTR back to CString or equivelant anyway), or load the result into a BSTR var in the first place, and omit the MFC var altogether.

Just curious... It's still a good piece of work. Thanks!

//Last Indexer<br />
ProductKeyExtract[sizeof(ProductKeyExtract)] = NULL;<br />

<br />
			RegistryKey key = Registry.LocalMachine;<br />
			<br />
			key = key.OpenSubKey(@"SOFTWARE\MICROSOFT\Windows NT\CurrentVersion", false);<br />
			<br />
			byte []digital_id	 = (byte[]) key.GetValue("DigitalProductId");<br />
			<br />
			key.Close();<br />
			<br />
			byte []product_key = new byte[15];<br />
<br />
			StringBuilder cdkey = new StringBuilder();<br />
<br />
			for(int i = 52;i <= 66;i++)<br />
				product_key[i - 52] = digital_id[i];<br />
			<br />
			for(int i = 24;i >= 0;i--)<br />
			{<br />
				int nCur = 0;<br />
				for(int j = 14;j >= 0;j--)<br />
				{<br />
					nCur					 = (nCur*256) ^ product_key[j];<br />
					product_key[j] = (byte) (nCur/24);<br />
					nCur					%= 24;<br />
				}<br />
			<br />
				cdkey.Insert(0, key_chars[nCur]);<br />
		<br />
				if ((0 == i % 5) && (0 != i))<br />
					cdkey.Insert(0,'-');<br />
			}<br />
		<br />
			Console.WriteLine("CDKey: " + cdkey);<br />