/******************************************************************************/
/* MCrypt, by LoRd_MuldeR <MuldeR2@GMX.de>                                    */
/* This work has been released under the CC0 1.0 Universal license!           */
/******************************************************************************/

#define WIN32_LEAN_AND_MEAN 1
#define _CRT_SECURE_NO_WARNINGS 1

#include <mcrypt.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <Windows.h>

static const uint64_t CRC64_TAB[256] =
{
	0x0000000000000000ULL,  0x42f0e1eba9ea3693ULL,
	0x85e1c3d753d46d26ULL,  0xc711223cfa3e5bb5ULL,
	0x493366450e42ecdfULL,  0x0bc387aea7a8da4cULL,
	0xccd2a5925d9681f9ULL,  0x8e224479f47cb76aULL,
	0x9266cc8a1c85d9beULL,  0xd0962d61b56fef2dULL,
	0x17870f5d4f51b498ULL,  0x5577eeb6e6bb820bULL,
	0xdb55aacf12c73561ULL,  0x99a54b24bb2d03f2ULL,
	0x5eb4691841135847ULL,  0x1c4488f3e8f96ed4ULL,
	0x663d78ff90e185efULL,  0x24cd9914390bb37cULL,
	0xe3dcbb28c335e8c9ULL,  0xa12c5ac36adfde5aULL,
	0x2f0e1eba9ea36930ULL,  0x6dfeff5137495fa3ULL,
	0xaaefdd6dcd770416ULL,  0xe81f3c86649d3285ULL,
	0xf45bb4758c645c51ULL,  0xb6ab559e258e6ac2ULL,
	0x71ba77a2dfb03177ULL,  0x334a9649765a07e4ULL,
	0xbd68d2308226b08eULL,  0xff9833db2bcc861dULL,
	0x388911e7d1f2dda8ULL,  0x7a79f00c7818eb3bULL,
	0xcc7af1ff21c30bdeULL,  0x8e8a101488293d4dULL,
	0x499b3228721766f8ULL,  0x0b6bd3c3dbfd506bULL,
	0x854997ba2f81e701ULL,  0xc7b97651866bd192ULL,
	0x00a8546d7c558a27ULL,  0x4258b586d5bfbcb4ULL,
	0x5e1c3d753d46d260ULL,  0x1cecdc9e94ace4f3ULL,
	0xdbfdfea26e92bf46ULL,  0x990d1f49c77889d5ULL,
	0x172f5b3033043ebfULL,  0x55dfbadb9aee082cULL,
	0x92ce98e760d05399ULL,  0xd03e790cc93a650aULL,
	0xaa478900b1228e31ULL,  0xe8b768eb18c8b8a2ULL,
	0x2fa64ad7e2f6e317ULL,  0x6d56ab3c4b1cd584ULL,
	0xe374ef45bf6062eeULL,  0xa1840eae168a547dULL,
	0x66952c92ecb40fc8ULL,  0x2465cd79455e395bULL,
	0x3821458aada7578fULL,  0x7ad1a461044d611cULL,
	0xbdc0865dfe733aa9ULL,  0xff3067b657990c3aULL,
	0x711223cfa3e5bb50ULL,  0x33e2c2240a0f8dc3ULL,
	0xf4f3e018f031d676ULL,  0xb60301f359dbe0e5ULL,
	0xda050215ea6c212fULL,  0x98f5e3fe438617bcULL,
	0x5fe4c1c2b9b84c09ULL,  0x1d14202910527a9aULL,
	0x93366450e42ecdf0ULL,  0xd1c685bb4dc4fb63ULL,
	0x16d7a787b7faa0d6ULL,  0x5427466c1e109645ULL,
	0x4863ce9ff6e9f891ULL,  0x0a932f745f03ce02ULL,
	0xcd820d48a53d95b7ULL,  0x8f72eca30cd7a324ULL,
	0x0150a8daf8ab144eULL,  0x43a04931514122ddULL,
	0x84b16b0dab7f7968ULL,  0xc6418ae602954ffbULL,
	0xbc387aea7a8da4c0ULL,  0xfec89b01d3679253ULL,
	0x39d9b93d2959c9e6ULL,  0x7b2958d680b3ff75ULL,
	0xf50b1caf74cf481fULL,  0xb7fbfd44dd257e8cULL,
	0x70eadf78271b2539ULL,  0x321a3e938ef113aaULL,
	0x2e5eb66066087d7eULL,  0x6cae578bcfe24bedULL,
	0xabbf75b735dc1058ULL,  0xe94f945c9c3626cbULL,
	0x676dd025684a91a1ULL,  0x259d31cec1a0a732ULL,
	0xe28c13f23b9efc87ULL,  0xa07cf2199274ca14ULL,
	0x167ff3eacbaf2af1ULL,  0x548f120162451c62ULL,
	0x939e303d987b47d7ULL,  0xd16ed1d631917144ULL,
	0x5f4c95afc5edc62eULL,  0x1dbc74446c07f0bdULL,
	0xdaad56789639ab08ULL,  0x985db7933fd39d9bULL,
	0x84193f60d72af34fULL,  0xc6e9de8b7ec0c5dcULL,
	0x01f8fcb784fe9e69ULL,  0x43081d5c2d14a8faULL,
	0xcd2a5925d9681f90ULL,  0x8fdab8ce70822903ULL,
	0x48cb9af28abc72b6ULL,  0x0a3b7b1923564425ULL,
	0x70428b155b4eaf1eULL,  0x32b26afef2a4998dULL,
	0xf5a348c2089ac238ULL,  0xb753a929a170f4abULL,
	0x3971ed50550c43c1ULL,  0x7b810cbbfce67552ULL,
	0xbc902e8706d82ee7ULL,  0xfe60cf6caf321874ULL,
	0xe224479f47cb76a0ULL,  0xa0d4a674ee214033ULL,
	0x67c58448141f1b86ULL,  0x253565a3bdf52d15ULL,
	0xab1721da49899a7fULL,  0xe9e7c031e063acecULL,
	0x2ef6e20d1a5df759ULL,  0x6c0603e6b3b7c1caULL,
	0xf6fae5c07d3274cdULL,  0xb40a042bd4d8425eULL,
	0x731b26172ee619ebULL,  0x31ebc7fc870c2f78ULL,
	0xbfc9838573709812ULL,  0xfd39626eda9aae81ULL,
	0x3a28405220a4f534ULL,  0x78d8a1b9894ec3a7ULL,
	0x649c294a61b7ad73ULL,  0x266cc8a1c85d9be0ULL,
	0xe17dea9d3263c055ULL,  0xa38d0b769b89f6c6ULL,
	0x2daf4f0f6ff541acULL,  0x6f5faee4c61f773fULL,
	0xa84e8cd83c212c8aULL,  0xeabe6d3395cb1a19ULL,
	0x90c79d3fedd3f122ULL,  0xd2377cd44439c7b1ULL,
	0x15265ee8be079c04ULL,  0x57d6bf0317edaa97ULL,
	0xd9f4fb7ae3911dfdULL,  0x9b041a914a7b2b6eULL,
	0x5c1538adb04570dbULL,  0x1ee5d94619af4648ULL,
	0x02a151b5f156289cULL,  0x4051b05e58bc1e0fULL,
	0x87409262a28245baULL,  0xc5b073890b687329ULL,
	0x4b9237f0ff14c443ULL,  0x0962d61b56fef2d0ULL,
	0xce73f427acc0a965ULL,  0x8c8315cc052a9ff6ULL,
	0x3a80143f5cf17f13ULL,  0x7870f5d4f51b4980ULL,
	0xbf61d7e80f251235ULL,  0xfd913603a6cf24a6ULL,
	0x73b3727a52b393ccULL,  0x31439391fb59a55fULL,
	0xf652b1ad0167feeaULL,  0xb4a25046a88dc879ULL,
	0xa8e6d8b54074a6adULL,  0xea16395ee99e903eULL,
	0x2d071b6213a0cb8bULL,  0x6ff7fa89ba4afd18ULL,
	0xe1d5bef04e364a72ULL,  0xa3255f1be7dc7ce1ULL,
	0x64347d271de22754ULL,  0x26c49cccb40811c7ULL,
	0x5cbd6cc0cc10fafcULL,  0x1e4d8d2b65facc6fULL,
	0xd95caf179fc497daULL,  0x9bac4efc362ea149ULL,
	0x158e0a85c2521623ULL,  0x577eeb6e6bb820b0ULL,
	0x906fc95291867b05ULL,  0xd29f28b9386c4d96ULL,
	0xcedba04ad0952342ULL,  0x8c2b41a1797f15d1ULL,
	0x4b3a639d83414e64ULL,  0x09ca82762aab78f7ULL,
	0x87e8c60fded7cf9dULL,  0xc51827e4773df90eULL,
	0x020905d88d03a2bbULL,  0x40f9e43324e99428ULL,
	0x2cffe7d5975e55e2ULL,  0x6e0f063e3eb46371ULL,
	0xa91e2402c48a38c4ULL,  0xebeec5e96d600e57ULL,
	0x65cc8190991cb93dULL,  0x273c607b30f68faeULL,
	0xe02d4247cac8d41bULL,  0xa2dda3ac6322e288ULL,
	0xbe992b5f8bdb8c5cULL,  0xfc69cab42231bacfULL,
	0x3b78e888d80fe17aULL,  0x7988096371e5d7e9ULL,
	0xf7aa4d1a85996083ULL,  0xb55aacf12c735610ULL,
	0x724b8ecdd64d0da5ULL,  0x30bb6f267fa73b36ULL,
	0x4ac29f2a07bfd00dULL,  0x08327ec1ae55e69eULL,
	0xcf235cfd546bbd2bULL,  0x8dd3bd16fd818bb8ULL,
	0x03f1f96f09fd3cd2ULL,  0x41011884a0170a41ULL,
	0x86103ab85a2951f4ULL,  0xc4e0db53f3c36767ULL,
	0xd8a453a01b3a09b3ULL,  0x9a54b24bb2d03f20ULL,
	0x5d45907748ee6495ULL,  0x1fb5719ce1045206ULL,
	0x919735e51578e56cULL,  0xd367d40ebc92d3ffULL,
	0x1476f63246ac884aULL,  0x568617d9ef46bed9ULL,
	0xe085162ab69d5e3cULL,  0xa275f7c11f7768afULL,
	0x6564d5fde549331aULL,  0x279434164ca30589ULL,
	0xa9b6706fb8dfb2e3ULL,  0xeb46918411358470ULL,
	0x2c57b3b8eb0bdfc5ULL,  0x6ea7525342e1e956ULL,
	0x72e3daa0aa188782ULL,  0x30133b4b03f2b111ULL,
	0xf7021977f9cceaa4ULL,  0xb5f2f89c5026dc37ULL,
	0x3bd0bce5a45a6b5dULL,  0x79205d0e0db05dceULL,
	0xbe317f32f78e067bULL,  0xfcc19ed95e6430e8ULL,
	0x86b86ed5267cdbd3ULL,  0xc4488f3e8f96ed40ULL,
	0x0359ad0275a8b6f5ULL,  0x41a94ce9dc428066ULL,
	0xcf8b0890283e370cULL,  0x8d7be97b81d4019fULL,
	0x4a6acb477bea5a2aULL,  0x089a2aacd2006cb9ULL,
	0x14dea25f3af9026dULL,  0x562e43b4931334feULL,
	0x913f6188692d6f4bULL,  0xd3cf8063c0c759d8ULL,
	0x5dedc41a34bbeeb2ULL,  0x1f1d25f19d51d821ULL,
	0xd80c07cd676f8394ULL,  0x9afce626ce85b507ULL,
};

static void erase(void *const ptr, const size_t length)
{
	volatile uint8_t* buffer = ptr;
	for (size_t i = 0U; i < length; ++i)
	{
		buffer[i] = 0U;
	}
}

static char* utf16_to_bytes(const wchar_t* const input, const UINT code_page)
{
	char* buffer;
	DWORD buffer_size = 0U, result = 0U;

	buffer_size = WideCharToMultiByte(code_page, 0, input, -1, NULL, 0, NULL, NULL);
	if (buffer_size < 1U)
	{
		return NULL;
	}

	buffer = (char*)malloc(sizeof(char) * buffer_size);
	if (!buffer)
	{
		return NULL;
	}

	result = WideCharToMultiByte(code_page, 0, input, -1, (LPSTR)buffer, buffer_size, NULL, NULL);
	if ((result > 0U) && (result <= buffer_size))
	{
		return buffer;
	}

	free(buffer);
	return NULL;
}

static void print_string(const char *const text, const size_t length)
{
	fputc('"', stderr);
	for (size_t i = 0; i < length; ++i)
	{
		fputc((text[i] >= 0x20) ? text[i] : '?', stderr);
	}
	fputs("\"\n\n", stderr);
}

static int open_files(FILE** const fin, FILE** const fout, const wchar_t* const input, const wchar_t* const output)
{
	*fin = _wfopen(input, L"rb");
	if (!(*fin))
	{
		fputws(L"Error: Failed to open input file for reading!\n\n", stderr);
		return 1;
	}

	*fout = _wfopen(output, L"wb");
	if (!(*fout))
	{
		fputws(L"Error: Failed to open output file for writing!\n\n", stderr);
		fclose(*fin);
		return 1;
	}

	return 0;
}

static uint64_t get_file_size(FILE *const file)
{
	struct _stati64 stat;
	if (_fstati64(_fileno(file), &stat) != 0)
	{
		fputws(L"I/O error: Failed to determine size of input file!\n\n", stderr);
		return UINT64_MAX;
	}
	return (stat.st_size >= 0) ? ((uint64_t)stat.st_size) : 0U;
}

static int encrypt(const wchar_t* const passphrase, const wchar_t* const input, const wchar_t* const output)
{
	mcrypt_t ctx = NULL;
	FILE *fin = NULL, *fout = NULL;
	int result = -1;

	char *const passphrase_utf8 = utf16_to_bytes(passphrase, CP_UTF8);
	if (!passphrase_utf8)
	{
		fputws(L"Error: Failed to convert passphrase to UTF-8 format!\n\n", stderr);
		goto clean_up;
	}

	if (open_files(&fin, &fout, input, output) != 0)
	{
		goto clean_up;;
	}

	uint64_t seed;
	if (mcrypt_generate_seed(&seed) != 0)
	{
		fputws(L"MCrypt error: Failed to generate seed!\n\n", stderr);
		goto  clean_up;
	}

	if (fwrite(&seed, sizeof(uint64_t), 1U, fout) < 1U)
	{
		fputws(L"I/O error: Failed to write seed value!\n\n", stderr);
		goto clean_up;
	}

	ctx = mcrypt_alloc(seed, passphrase_utf8);
	if (!ctx)
	{
		fputws(L"MCrypt error: Failed to initialize encryption!\n\n", stderr);
		goto clean_up;
	}

	fputws(L"Encrypting, please be patient... ", stderr);

	uint8_t buffer[1024U];
	uint64_t crc_actual = ~0U;

	while (!feof(fin))
	{
		const size_t count = fread(buffer, sizeof(uint8_t), 1024U, fin);
		if (ferror(fin))
		{
			fputws(L"failed!\n\nI/O error: Failed to read input data!\n\n", stderr);
			goto clean_up;
		}
		if (count > 0U)
		{
			for (size_t i = 0U; i < count; ++i)
			{
				crc_actual = CRC64_TAB[((crc_actual >> 56) ^ buffer[i]) & 0xFF] ^ (crc_actual << 8);
			}
			if (mcrypt_enc_process_inplace(ctx, buffer, count) != 0)
			{
				fputws(L"failed!\n\nMCrypt error: Failed to encrypt data!\n\n", stderr);
				goto  clean_up;
			}
			if (fwrite(buffer, sizeof(uint8_t), count, fout) < count)
			{
				fputws(L"failed!\n\nI/O error: Failed to write encrypted data!\n\n", stderr);
				goto clean_up;
			}
		}
	}

	crc_actual ^= ~0U;

	if (fwrite(&crc_actual, sizeof(uint64_t), 1U, fout) < 1U)
	{
		fputws(L"failed!\n\nI/O error: Failed to write CRC checksum!\n\n", stderr);
		goto clean_up;
	}

	result = 0;

	fputws(L"done.\n\n", stderr);
	fflush(stderr);

clean_up:

	if (ctx)
	{
		mcrypt_free(ctx);
	}

	if (fout)
	{
		fclose(fout);
	}

	if (fin)
	{
		fclose(fin);
	}

	if (passphrase_utf8)
	{
		erase(passphrase_utf8, strlen(passphrase_utf8));
		free(passphrase_utf8);
	}

	return result;
}

static int decrypt(const wchar_t* const passphrase, const wchar_t* const input, const wchar_t* const output)
{
	mcrypt_t ctx = NULL;
	FILE *fin = NULL, *fout = NULL;
	int result = -1;

	char *const passphrase_utf8 = utf16_to_bytes(passphrase, CP_UTF8);
	if (!passphrase_utf8)
	{
		fputws(L"Error: Failed to convert passphrase to UTF-8 format!\n\n", stderr);
		goto clean_up;
	}

	if (open_files(&fin, &fout, input, output) != 0)
	{
		goto clean_up;
	}

	const uint64_t file_size = get_file_size(fin);
	if (file_size == UINT64_MAX)
	{
		goto clean_up;
	}

	if (file_size < 16LL)
	{
		fputws(L"Error: Input file is too small!\n\n", stderr);
		goto clean_up;
	}

	uint64_t seed;
	if (fread(&seed, sizeof(uint64_t), 1U, fin) < 1U)
	{
		fputws(L"I/O error: Failed to read seed value!\n\n", stderr);
		goto clean_up;
	}

	ctx = mcrypt_alloc(seed, passphrase_utf8);
	if (!ctx)
	{
		fputws(L"MCrypt error: Failed to initialize decryption!\n\n", stderr);
		goto clean_up;
	}

	fputws(L"Decrypting, please be patient... ", stderr);
	
	uint64_t crc_actual = ~0U;
	int64_t bytes_read = sizeof(uint64_t);
	uint8_t buffer[1024U];

	const int64_t read_limit = file_size - sizeof(uint64_t);
	while ((!feof(fin)) && (bytes_read < read_limit))
	{
		const int64_t bytes_remaining = read_limit - bytes_read;
		const size_t read_len = (bytes_remaining < 1024U) ? ((size_t)bytes_remaining) : 1024U;
		const size_t count = fread(buffer, sizeof(uint8_t), read_len, fin);
		if (ferror(fin))
		{
			fputws(L"failed!\n\nI/O error: Failed to read encrypted data!\n\n", stderr);
			goto clean_up;
		}
		if (count > 0U)
		{
			bytes_read += count;
			if (mcrypt_dec_process_inplace(ctx, buffer, count) != 0)
			{
				fputws(L"failed!\n\nMCrypt error: Failed to decrypt data!\n\n", stderr);
				goto clean_up;
			}
			for (size_t i = 0U; i < count; ++i)
			{
				crc_actual = CRC64_TAB[((crc_actual >> 56) ^ buffer[i]) & 0xFF] ^ (crc_actual << 8);
			}
			if (fwrite(buffer, sizeof(uint8_t), count, fout) < count)
			{
				fputws(L"failed!\n\nI/O error: Failed to write decrypted data!\n\n", stderr);
				goto clean_up;
			}
		}
	}

	crc_actual ^= ~0U;

	if (bytes_read < read_limit)
	{
		fputws(L"failed!\n\nI/O error: Input file could not be fully read!\n\n", stderr);
		goto clean_up;
	}

	uint64_t crc_expected;
	if (fread(&crc_expected, sizeof(uint64_t), 1U, fin) < 1U)
	{
		fputws(L"failed!\n\nI/O error: Failed to read CRC checksum!\n\n", stderr);
		goto clean_up;
	}

	if (crc_actual != crc_expected)
	{
		fwprintf(stderr, L"failed!\n\nCRC error: Checksum mismatch detected! [0x%016llX vs. 0x%016llX]\n\nWrong passphrase?\n\n", crc_actual, crc_expected);
		goto clean_up;
	}

	result = 0;

	fputws(L"done.\n\nCRC checksum is correct.\n\n", stderr);
	fflush(stderr);

clean_up:

	if (ctx)
	{
		mcrypt_free(ctx);
	}

	if (fout)
	{
		fclose(fout);
	}

	if (fin)
	{
		fclose(fin);
	}

	if (passphrase_utf8)
	{
		erase(passphrase_utf8, strlen(passphrase_utf8));
		free(passphrase_utf8);
	}

	return result;
}

int wmain(int argc, wchar_t* argv[])
{
	fwprintf(stderr, L"MCrypt Utility [%S]\n", __DATE__" "__TIME__);
	fwprintf(stderr, L"Powered by libMCrypt v%S [%S]\n\n", LIBMCRYPT_VERSION, LIBMCRYPT_BUILDNO);

	if (argc < 4)
	{
		fputws(L"Usage:\n", stderr);
		fwprintf(stderr, L"  %s [--decrypt] <passphrase> <input> <output>\n\n", argv[0U]);
		return 1;
	}

	int result = -1;
	const clock_t clk_start = clock();

	if ((argc > 4) && (!_wcsicmp(argv[1U], L"--decrypt")))
	{
		result = decrypt(argv[2U], argv[3U], argv[4U]);
		erase(argv[2U], wcslen(argv[2U]) * sizeof(wchar_t));
	}
	else
	{
		result = encrypt(argv[1U], argv[2U], argv[3U]);
		erase(argv[1U], wcslen(argv[1U]) * sizeof(wchar_t));
	}

	fputws(L"--------\n\n", stderr);
	fflush(stderr);

	const clock_t clk_end = clock();
	fwprintf(stderr, L"Operation completed after %.1f seconds.\n\n", (clk_end - clk_start) / ((double)CLOCKS_PER_SEC));
}