Windows Product Key viewer (incl. Windows 10)

main.cpp

#include "stdafx.h"

#include <Windows.h>
#include <intrin.h>
#include <atlstr.h>
#include <wbemidl.h>
#include <comdef.h>
#include <Strsafe.h>

#include <stdio.h>
#include <conio.h>

#include <string>
#include <iostream>

int main()
{
	HKEY hRegistryKey;
	BYTE *DigitalProductID = NULL;
	DWORD DataLength;

	int isWin10Key = 0;

	if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, TEXT("SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion"),
		0, KEY_QUERY_VALUE | KEY_WOW64_64KEY, &hRegistryKey) == ERROR_SUCCESS)
	{
		DataLength = 164;
		DigitalProductID = (BYTE *)malloc(DataLength);
		memset(DigitalProductID, 0, DataLength);

		if (RegQueryValueEx(hRegistryKey, TEXT("DigitalProductId"),
			0, NULL, DigitalProductID, &DataLength) == ERROR_SUCCESS)
		{
			isWin10Key = (byte)((DigitalProductID[66] / 6) & 1);
			DigitalProductID[66] = (byte)((DigitalProductID[66] & 0xF7) | ((isWin10Key & 2) * 4));
		}
	}

	std::string pkey;
	const std::string digits = "BCDFGHJKMPQRTVWXY2346789";
	int last = 0;
	for (int i = 24; i >= 0; i--) {
		int current = 0;

		for (int j = 14; j >= 0; j--) {
			current = current * 256;
			current = DigitalProductID[j + 52] + current;
			DigitalProductID[j + 52] = (BYTE)(current / 24);
			current = current % 24;
			last = current;
		}
		pkey = digits[current] + pkey;
	}

	RegCloseKey(hRegistryKey);
	if (DigitalProductID) free(DigitalProductID);
	std::string productKey;
	if (isWin10Key != 0) {
		productKey = pkey;
		std::string keypart1 = productKey.substr(1, last);
		std::string keypart2 = productKey.substr(last + 1, productKey.length() - (last + 1));
		productKey = keypart1 + "N" + keypart2;
	}
	else {
		productKey = pkey;
	}

	for (unsigned int i = 5; i < productKey.length(); i += 6) {
		productKey = productKey.insert(i, "-");
	}

	std::cout << productKey;
	std::getchar();

	return 0;
}