keyfile_generator.cpp

#include <Windows.h>
#include <algorithm>
#include <iostream>
#include <ctime>

u_char TABLE_[] = {
	0x00, 0x02, 0x04, 0x06, 0x08, 0x0A, 0x0C, 0x0E, 0x10, 0x12, 0x14, 0x16, 0x18, 0x1A, 0x1C, 0x1E,
	0x20, 0x22, 0x24, 0x26, 0x28, 0x2A, 0x2C, 0x2E, 0x30, 0x32, 0x34, 0x36, 0x38, 0x3A, 0x3C, 0x3E,
	0x40, 0x42, 0x44, 0x46, 0x48, 0x4A, 0x4C, 0x4E, 0x50, 0x52, 0x54, 0x56, 0x58, 0x5A, 0x5C, 0x5E,
	0x60, 0x62, 0x64, 0x66, 0x68, 0x6A, 0x6C, 0x6E, 0x70, 0x72, 0x74, 0x76, 0x78, 0x7A, 0x7C, 0x7E,
	0x80, 0x82, 0x84, 0x86, 0x88, 0x8A, 0x8C, 0x8E, 0x90, 0x92, 0x94, 0x96, 0x98, 0x9A, 0x9C, 0x9E,
	0xA0, 0xA2, 0xA4, 0xA6, 0xA8, 0xAA, 0xAC, 0xAE, 0xB0, 0xB2, 0xB4, 0xB6, 0xB8, 0xBA, 0xBC, 0xBE,
	0xC0, 0xC2, 0xC4, 0xC6, 0xC8, 0xCA, 0xCC, 0xCE, 0xD0, 0xD2, 0xD4, 0xD6, 0xD8, 0xDA, 0xDC, 0xDE,
	0xE0, 0xE2, 0xE4, 0xE6, 0xE8, 0xEA, 0xEC, 0xEE, 0xF0, 0xF2, 0xF4, 0xF6, 0xF8, 0xFA, 0xFC, 0xFE,
	0x1B, 0x19, 0x1F, 0x1D, 0x13, 0x11, 0x17, 0x15, 0x0B, 0x09, 0x0F, 0x0D, 0x03, 0x01, 0x07, 0x05,
	0x3B, 0x39, 0x3F, 0x3D, 0x33, 0x31, 0x37, 0x35, 0x2B, 0x29, 0x2F, 0x2D, 0x23, 0x21, 0x27, 0x25,
	0x5B, 0x59, 0x5F, 0x5D, 0x53, 0x51, 0x57, 0x55, 0x4B, 0x49, 0x4F, 0x4D, 0x43, 0x41, 0x47, 0x45,
	0x7B, 0x79, 0x7F, 0x7D, 0x73, 0x71, 0x77, 0x75, 0x6B, 0x69, 0x6F, 0x6D, 0x63, 0x61, 0x67, 0x65,
	0x9B, 0x99, 0x9F, 0x9D, 0x93, 0x91, 0x97, 0x95, 0x8B, 0x89, 0x8F, 0x8D, 0x83, 0x81, 0x87, 0x85,
	0xBB, 0xB9, 0xBF, 0xBD, 0xB3, 0xB1, 0xB7, 0xB5, 0xAB, 0xA9, 0xAF, 0xAD, 0xA3, 0xA1, 0xA7, 0xA5,
	0xDB, 0xD9, 0xDF, 0xDD, 0xD3, 0xD1, 0xD7, 0xD5, 0xCB, 0xC9, 0xCF, 0xCD, 0xC3, 0xC1, 0xC7, 0xC5,
	0xFB, 0xF9, 0xFF, 0xFD, 0xF3, 0xF1, 0xF7, 0xF5, 0xEB, 0xE9, 0xEF, 0xED, 0xE3, 0xE1, 0xE7, 0xE5,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

int main()
{
start_:
	srand(time(0));
	u_char key[4]{};


	u_char al, cl;
	do {
		key[0] = 0x20 + rand() % (0x7F - 0x20);
		al = key[0];
		u_char bl = al; // key[0]
		cl = bl; // key[0]
		DWORD ebx = (DWORD)bl << 4;
		al &= 0xF;
		DWORD ecx = (DWORD)cl >> 4; 
		cl = ecx & 0xF;             
	} while (al == cl); // e.g "(0x22), 3(0x33), D(0x44), U(0x55), f(0x66), w(0x77)

	key[1] = (key[0] << 4) | ((key[0] >> 4) & 0xF); // e.g. 0x46 >>> 0x64

	key[2] = key[0] + key[1];

	key[3] = 0;

	u_char middle_[17]{};
	u_char org_middle_[17]{};

	// Generate randomly 
	for (size_t i = 0; i < 17; i++)
	{
		middle_[i] = 0x20 + rand() % (0x7F - 0x20);
	}
	std::copy(std::begin(middle_), std::end(middle_), org_middle_);

	u_char last_[17]{};

	// loop_1
	__asm {
		lea esi, middle_;
		mov ecx, 13;
	loop_1:
		lodsd;
		xor eax, 0x1BADC0DE;
		bswap eax;
		not al;
		rol eax, cl;
		inc ecx;
		bswap eax;
		ror eax, cl;
		dec ecx;
		not eax;
		xor eax, 0x98765432;
		xchg al, ah;
		mov [esi - 4], eax;
		sub esi, 3;
		loop loop_1;
	}

	// loop_2
	for (size_t i = 0; i < 16; i++)
	{
		middle_[i] ^= key[2];
	}

	size_t i = 0;
	BOOL flag = FALSE;
	for (u_char a = 0; a < 0xFF; a++)
	{
		for (u_char b = 0; b < 0xFF; b++)
		{
			for (u_char c = 0; c < 0xFF; c++)
			{
				for (u_char d = 0; d < 0xFF; d++)
				{
					u_char ah = a ^ b ^ c ^ d;

					u_char al = a ^ b;
					al = TABLE_[al]; // xlat
					al ^= ah;
					al ^= a;
					if (al != middle_[i])
						continue;
					last_[i] = a;

					al = b ^ c;
					al = TABLE_[al];
					al ^= ah;
					al ^= b;
					if (al != middle_[i + 0x4])
						continue;
					last_[i + 4] = b;
					
					al = c ^ d;
					al = TABLE_[al];
					al ^= ah;
					al ^= c;
					if (al != middle_[i + 0x8])
						continue;
					last_[i + 0x8] = c;

					al = d ^ a;
					al = TABLE_[al];
					al ^= ah;
					al ^= d;
					if (al != middle_[i + 0xC])
						continue;
					last_[i + 0xC] = d;
					i++;
					a = b = c = d = 0;
					if (i >= 4) {
						flag = TRUE;
						goto NEXT;
					}
				}
			}
		}
	}
NEXT:
	if (!flag) {
		std::cout << "\nCan not generate keyfile\nNext Try...";
		goto start_;
	}

	HANDLE f = CreateFile(L"\\Path\\to\\keyme.exe\\reginf.k23", GENERIC_WRITE, 0, NULL,
		CREATE_ALWAYS, 0, NULL);
	if (!f) {
		std::cout << "Can not create file...\n";
		getchar();
		return 1;
	}
	u_char buf[] = { key[0], key[1], key[2], key[3] };
	for (size_t i = 0; i < 4; i++)
	{
		WriteFile(f, &buf[i], sizeof(u_char), NULL, NULL);
	}

	WriteFile(f, org_middle_, 16, NULL, NULL);

	WriteFile(f, last_, 16, NULL, NULL);

	CloseHandle(f);

    return 0;
}