SlunkCrypt/frontend/src/main.c

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

#ifdef _WIN32
#	define _CRT_SECURE_NO_WARNINGS 1
#else
#	define _GNU_SOURCE 1
#endif

/* API */
#include <slunkcrypt.h>

/* CLI */
#include "utils.h"
#include "blake2.h"
#include "test.h"

/* CRT */
#include <string.h>
#include <time.h>
#include <inttypes.h>
#include <ctype.h>
#include <signal.h>
#include <assert.h>

// ==========================================================================
// Constants
// ==========================================================================

#define BUFFER_SIZE 4096U

#define MODE_HELP 0
#define MODE_VERS 1
#define MODE_ENCR 2
#define MODE_DECR 3
#define MODE_PASS 4
#define MODE_TEST 5

#define PW_FROM_ENV (!(argc > 4))

static const CHR* const ENV_PASSWORD = T("SLUNK_PASSPHRASE");
static const CHR* const ENV_KEEPFILE = T("SLUNK_KEEP_INCOMPLETE");

static const CHR* const PREFIX_PASS = T("pass:");
static const CHR* const PREFIX_FILE = T("file:");

static const char PASSWD_SYMBOLS[] =
{
	'!', '#', '$', '%', '&', '(', ')', '*', '+', ',', '-', '.', '/', '0', '1',
	'2', '3', '4', '5', '6', '7', '8', '9', ':', ';', '<', '=', '>', '?', '@',
	'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
	'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '[', ']', '^', '_',
	'a', 'b', 'c', 'd',	'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
	'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '{', '|', '}', '~'
};

static const size_t RCMD_PWDLEN_LENGTH = 12U;
static const size_t DFLT_PWDLEN_LENGTH = 20U;

static const clock_t UPDATE_INTERVAL = (clock_t)(1.5708 * CLOCKS_PER_SEC);

static const uint64_t MAGIC_NUMBER = 0x243F6A8885A308D3ull;

// ==========================================================================
// Auxiliary functions
// ==========================================================================

static int parse_slunk_mode(const CHR* const command)
{
	if ((!STRICMP(command, T("-h"))) || (!STRICMP(command, T("/?"))) || (!STRICMP(command, T("--help"))))
	{
		return MODE_HELP;
	}
	else if ((!STRICMP(command, T("-v"))) || (!STRICMP(command, T("--version"))))
	{
		return MODE_VERS;
	}
	else if ((!STRICMP(command, T("-e"))) || (!STRICMP(command, T("--encrypt"))))
	{
		return MODE_ENCR;
	}
	else if ((!STRICMP(command, T("-d"))) || (!STRICMP(command, T("--decrypt"))))
	{
		return MODE_DECR;
	}
	else if ((!STRICMP(command, T("-p"))) || (!STRICMP(command, T("--make-pw"))))
	{
		return MODE_PASS;
	}
	else if ((!STRICMP(command, T("-t"))) || (!STRICMP(command, T("--self-test"))))
	{
		return MODE_TEST;
	}
	else
	{
		return -1; /*invalid command*/
	}
}

static void print_manpage(const CHR *const program)
{
	FPUTS(T("====================================================================\n"), stderr);
	FPUTS(T("This software has been released under the CC0 1.0 Universal license:\n"), stderr);
	FPUTS(T("https://creativecommons.org/publicdomain/zero/1.0/legalcode\n"), stderr);
	FPUTS(T("====================================================================\n\n"), stderr);
	FPUTS(T("Usage:\n"), stderr);
	FPRINTF(stderr, T("  %") T(PRISTR) T(" --encrypt [pass:<pass>|file:<file>] <input.txt> <output.enc>\n"), program);
	FPRINTF(stderr, T("  %") T(PRISTR) T(" --decrypt [pass:<pass>|file:<file>] <input.enc> <output.txt>\n"), program);
	FPRINTF(stderr, T("  %") T(PRISTR) T(" --make-pw [<length>]\n\n"), program);
	FPRINTF(stderr, T("Optionally, reads passphrase from the %") T(PRISTR) T(" environment variable.\n\n"), ENV_PASSWORD);
}

static char *copy_passphrase(const CHR *const passphrase)
{
	if ((!passphrase) || (!passphrase[0U]))
	{
		FPUTS(T("Error: The passphrase input string must not be empty!\n\n"), stderr);
		return NULL;
	}

	char *const buffer = CHR_to_utf8(passphrase);
	if (!buffer)
	{
		FPUTS(T("Error: Failed to allocate the string buffer!\n\n"), stderr);
	}

	return buffer;
}

static char *read_passphrase(const CHR *const file_name)
{
	if ((!file_name) || (!file_name[0U]))
	{
		FPUTS(T("Error: The passphrase input file name must not be empty!\n\n"), stderr);
		return NULL;
	}

	const size_t max_len = SLUNKCRYPT_PWDLEN_MAX + 2U;
	char *const buffer = (char*) malloc(max_len * sizeof(char));
	if (!buffer)
	{
		FPUTS(T("Error: Failed to allocate the passphrase buffer!\n\n"), stderr);
		return NULL;
	}

	const int use_stdin = (!file_name) || (!STRICMP(file_name, T("-")));
	FILE *const file_in = use_stdin ? stdin : FOPEN(file_name, T("rb"));
	if (!file_in)
	{
		FPRINTF(stderr, T("Error: Failed to open input file \"%") T(PRISTR) T("\" for reading!\n\n"), file_name);
		free(buffer);
		return NULL;
	}

	do
	{
		if (!fgets(buffer, (int)max_len, file_in))
		{
			buffer[0U] = '\0';
			goto finish;
		}
		size_t length = strlen(buffer);
		while ((length > 0U) && ((buffer[length - 1U] == '\r') || (buffer[length - 1U] == '\n')))
		{
			buffer[--length] = '\0';
		}
	}
	while (!buffer[0U]);

finish:

	if ((!use_stdin) && file_in)
	{
		fclose(file_in);
	}

	return buffer;
}

static int weak_passphrase(const char *str)
{
	int flags[4U] = { 0, 0, 0, 0 };
	while (*str)
	{
		const int c = *str++;
		if (isalpha(c))
		{
			flags[isupper(c) ? 0U : 1U] = 1;
		}
		else 
		{
			flags[isdigit(c) ? 2U : 3U] = 1;
		}
	}
	const int strong = flags[0U] && flags[1U] && flags[2U] && flags[3U];
	return !strong;
}

static int generate_passphrase(const size_t length)
{
	int result = EXIT_FAILURE;
	const size_t passwd_len = BOUND(SLUNKCRYPT_PWDLEN_MIN, length, SLUNKCRYPT_PWDLEN_MAX);

	char *const buffer = (char*) malloc((passwd_len + 1U) * sizeof(char));
	if (!buffer)
	{
		FPUTS(T("Error: Failed to allocate memory buffer!\n\n"), stderr);
		return EXIT_FAILURE;
	}

	do
	{
		for (size_t i = 0U; i < passwd_len; ++i)
		{
			uint64_t value;
			if (slunkcrypt_generate_nonce(&value) != SLUNKCRYPT_SUCCESS)
			{
				FPUTS(T("Error: Failed to generate next random number!\n\n"), stderr);
				goto clean_up;
			}
			buffer[i] = PASSWD_SYMBOLS[value % ARRAY_SIZE(PASSWD_SYMBOLS)];
		}
		buffer[passwd_len] = '\0';
	}
	while ((!isalpha((int)buffer[0U])) || (!isalnum((int)buffer[passwd_len - 1U])) || weak_passphrase(buffer));

	FPRINTF(stdout, T("%") T(PRIstr) T("\n\n"), buffer);
	fflush(stdout);
	result = EXIT_SUCCESS;

clean_up:

	if (buffer)
	{
		slunkcrypt_bzero(buffer, passwd_len * sizeof(char));
		free(buffer);
	}

	return result;
}

static int open_files(FILE **const file_in, FILE **const file_out, const CHR *const input_path, const CHR *const output_path)
{
	if (!(*file_in = FOPEN(input_path, T("rb"))))
	{
		FPRINTF(stderr, T("Error: Failed to open input file \"%") T(PRISTR) T("\" for reading!\n\n"), input_path);
		*file_out = NULL;
		return EXIT_FAILURE;
	}

	if (!(*file_out = FOPEN(output_path, T("wb"))))
	{
		FPRINTF(stderr, T("Error: Failed to open output file \"%") T(PRISTR) T("\" for writing!\n\n"), output_path);
		return EXIT_FAILURE;
	}

	return EXIT_SUCCESS;
}

static int remove_incomplete_files(void)
{
	const CHR* const keep_files = GETENV(ENV_KEEPFILE);
	if (keep_files)
	{
		return (!STRTOUL(keep_files));
	}
	return 1;
}

static void sigint_handler(const int sig)
{
	if (sig == SIGINT)
	{
		g_slunkcrypt_abort_flag = 1;
	}
}

// ==========================================================================
// Encrypt
// ==========================================================================

static int encrypt(const char* const passphrase, const CHR* const input_path, const CHR* const output_path)
{
	slunkcrypt_t ctx = SLUNKCRYPT_NULL;
	FILE *file_in = NULL, *file_out = NULL;
	int result = EXIT_FAILURE, status;

	if (open_files(&file_in, &file_out, input_path, output_path) != EXIT_SUCCESS)
	{
		goto clean_up;
	}

	const uint64_t file_size = get_file_size(file_in);
	if (file_size == UINT64_MAX)
	{
		FPUTS(T("I/O error: Failed to determine size of input file!\n\n"), stderr);
		goto clean_up;
	}
	else if (file_size < 1U)
	{
		FPUTS(T("Error: Input file is empty or an unsupported type!\n\n"), stderr);
		goto clean_up;
	}

	FPUTS(T("Encrypting file contents, please be patient... "), stderr);
	fflush(stderr);

	uint64_t nonce;
	if (slunkcrypt_generate_nonce(&nonce) != SLUNKCRYPT_SUCCESS)
	{
		FPUTS(T("\n\nSlunkCrypt error: Failed to generate nonce!\n\n"), stderr);
		goto  clean_up;
	}

	ctx = slunkcrypt_alloc(nonce, (const uint8_t*)passphrase, strlen(passphrase), SLUNKCRYPT_ENCRYPT);
	if (!ctx)
	{
		FPUTS(g_slunkcrypt_abort_flag ? T("\n\nProcess interrupted!\n\n") : T("\n\nSlunkCrypt error: Failed to initialize encryption!\n\n"), stderr);
		goto clean_up;
	}

	if (fwrite_ui64(nonce ^ MAGIC_NUMBER, file_out) < 1U)
	{
		FPUTS(T("\n\nI/O error: Failed to write nonce value!\n\n"), stderr);
		goto clean_up;
	}

	unsigned refresh_cycles = 0U;
	clock_t clk_update = clock();
	uint64_t bytes_read = 0U;
	uint8_t buffer[BUFFER_SIZE];

	blake2s_t blake2s_state;
	blake2s_init(&blake2s_state);

	FPRINTF(stderr, T("%5.1f%% "), 0.0);
	fflush(stderr);

	while (bytes_read < file_size)
	{
		const uint64_t bytes_remaining = file_size - bytes_read;
		const size_t request_len = (bytes_remaining < BUFFER_SIZE) ? ((size_t)bytes_remaining) : BUFFER_SIZE;
		const size_t count = fread(buffer, sizeof(uint8_t), request_len, file_in);
		if (count > 0U)
		{
			blake2s_update(&blake2s_state, buffer, count);
			bytes_read += count;
			if ((status = slunkcrypt_inplace(ctx, buffer, count)) != SLUNKCRYPT_SUCCESS)
			{
				FPUTS((status == SLUNKCRYPT_ABORTED) ? T("\n\nProcess interrupted!\n\n") : T("\n\nSlunkCrypt error: Failed to encrypt data!\n\n"), stderr);
				goto clean_up;
			}
			if (fwrite(buffer, sizeof(uint8_t), count, file_out) < count)
			{
				FPUTS(T("\n\nI/O error: Failed to write encrypted data!\n\n"), stderr);
				goto clean_up;
			}
		}
		if (count < request_len)
		{
			break; /*EOF*/
		}
		if (!(++refresh_cycles & 0x1F))
		{
			const clock_t clk_now = clock();
			if ((clk_now < clk_update) || (clk_now - clk_update > UPDATE_INTERVAL))
			{
				FPRINTF(stderr, T("\b\b\b\b\b\b\b%5.1f%% "), (bytes_read / ((double)file_size)) * 100.0);
				fflush(stderr);
				clk_update = clk_now;
			}
		}
	}

	if (ferror(file_in))
	{
		FPUTS(T("\n\nI/O error: Failed to read input data!\n\n"), stderr);
		goto clean_up;
	}

	if (bytes_read != file_size)
	{
		FPUTS(T("\n\nI/O error: Input file could not be fully read!\n\n"), stderr);
		goto clean_up;
	}

	const size_t padding = sizeof(uint64_t) - (file_size % sizeof(uint64_t));
	assert(padding && (padding <= sizeof(uint64_t)));
	if (slunkcrypt_random_bytes(buffer, padding) < padding)
	{
		FPUTS(T("\n\nSlunkCrypt error: Failed to generate random data!\n\n"), stderr);
		goto clean_up;
	}

	SET_LOWBITS(buffer[padding - 1U], padding - 1U);
	if ((status = slunkcrypt_inplace(ctx, buffer, padding)) != SLUNKCRYPT_SUCCESS)
	{
		FPUTS((status == SLUNKCRYPT_ABORTED) ? T("\n\nProcess interrupted!\n\n") : T("\n\nSlunkCrypt error: Failed to encrypt data!\n\n"), stderr);
		goto clean_up;
	}

	if (fwrite(buffer, sizeof(uint8_t), padding, file_out) < padding)
	{
		FPUTS(T("\n\nI/O error: Failed to write padding data!\n\n"), stderr);
		goto clean_up;
	}

	uint8_t checksum_buffer[sizeof(uint64_t)];
	store_ui64(checksum_buffer, blake2s_final(&blake2s_state));

	if ((status = slunkcrypt_inplace(ctx, checksum_buffer, sizeof(uint64_t))) != SLUNKCRYPT_SUCCESS)
	{
		FPUTS((status == SLUNKCRYPT_ABORTED) ? T("\n\nProcess interrupted!\n\n") : T("\n\nSlunkCrypt error: Failed to encrypt checksum!\n\n"), stderr);
		goto  clean_up;
	}

	if (fwrite(checksum_buffer, sizeof(uint8_t), sizeof(uint64_t), file_out) < sizeof(uint64_t))
	{
		FPUTS(T("\n\nI/O error: Failed to write the checksum!\n\n"), stderr);
		goto clean_up;
	}

	FPRINTF(stderr, T("\b\b\b\b\b\b\b%5.1f%%\n\n"), 100.0);
	fflush(stderr);

	result = EXIT_SUCCESS;

	FPUTS(T("All is done.\n\n"), stderr);
	fflush(stderr);

clean_up:

	if (ctx)
	{
		slunkcrypt_free(ctx);
	}

	if (file_out)
	{
		fclose(file_out);
		if ((result != EXIT_SUCCESS) && remove_incomplete_files())
		{
			if (REMOVE(output_path))
			{
				FPUTS(T("Warning: Failed to remove incomplete output file!\n\n"), stderr);
			}
		}
	}

	if (file_in)
	{
		fclose(file_in);
	}

	slunkcrypt_bzero(buffer, BUFFER_SIZE);
	slunkcrypt_bzero(checksum_buffer, sizeof(uint64_t));
	slunkcrypt_bzero(&blake2s_state, sizeof(blake2s_t));
	slunkcrypt_bzero(&nonce, sizeof(uint64_t));

	return result;
}

// ==========================================================================
// Decrypt
// ==========================================================================

static int decrypt(const char* const passphrase, const CHR* const input_path, const CHR* const output_path)
{
	slunkcrypt_t ctx = SLUNKCRYPT_NULL;
	FILE *file_in = NULL, *file_out = NULL;
	int result = EXIT_FAILURE, status;

	if (open_files(&file_in, &file_out, input_path, output_path) != EXIT_SUCCESS)
	{
		goto clean_up;
	}

	const uint64_t file_size = get_file_size(file_in);
	if (file_size == UINT64_MAX)
	{
		FPUTS(T("I/O error: Failed to determine size of input file!\n\n"), stderr);
		goto clean_up;
	}
	else if (file_size < (3U * sizeof(uint64_t)))
	{
		FPUTS(T("Error: Input file is too small! Truncated?\n\n"), stderr);
		goto clean_up;
	}
	else if ((file_size % sizeof(uint64_t)) != 0)
	{
		FPRINTF(stderr, T("Warning: File size is *not* an integer multiple of %u, ignoring excess bytes!\n\n"), (unsigned)sizeof(uint64_t));
	}

	FPUTS(T("Decrypting file contents, please be patient... "), stderr);
	fflush(stderr);

	uint64_t nonce;
	if (fread_ui64(&nonce, file_in) < 1U)
	{
		FPUTS(T("\n\nI/O error: Failed to read nonce value!\n\n"), stderr);
		goto clean_up;
	}

	ctx = slunkcrypt_alloc(nonce ^ MAGIC_NUMBER, (const uint8_t*)passphrase, strlen(passphrase), SLUNKCRYPT_DECRYPT);
	if (!ctx)
	{
		FPUTS(g_slunkcrypt_abort_flag ? T("\n\nProcess interrupted!\n\n") : T("\n\nSlunkCrypt error: Failed to initialize decryption!\n\n"), stderr);
		goto clean_up;
	}
	
	unsigned refresh_cycles = 0U;
	clock_t clk_update = clock();
	uint64_t bytes_read = sizeof(uint64_t);
	uint8_t buffer[BUFFER_SIZE];

	const uint64_t read_limit = round_down(file_size, sizeof(uint64_t)) - (2U * sizeof(uint64_t));

	blake2s_t blake2s_state;
	blake2s_init(&blake2s_state);

	FPRINTF(stderr, T("%5.1f%% "), 0.0);
	fflush(stderr);

	while (bytes_read < read_limit)
	{
		const uint64_t bytes_remaining = read_limit - bytes_read;
		const size_t request_len = (bytes_remaining < BUFFER_SIZE) ? ((size_t)bytes_remaining) : BUFFER_SIZE;
		const size_t count = fread(buffer, sizeof(uint8_t), request_len, file_in);
		if (count > 0U)
		{
			bytes_read += count;
			if ((status = slunkcrypt_inplace(ctx, buffer, count)) != SLUNKCRYPT_SUCCESS)
			{
				FPUTS((status == SLUNKCRYPT_ABORTED) ? T("\n\nProcess interrupted!\n\n") : T("\n\nSlunkCrypt error: Failed to decrypt data!\n\n"), stderr);
				goto clean_up;
			}
			blake2s_update(&blake2s_state, buffer, count);
			if (fwrite(buffer, sizeof(uint8_t), count, file_out) < count)
			{
				FPUTS(T("failed!\n\nI/O error: Failed to write decrypted data!\n\n"), stderr);
				goto clean_up;
			}
		}
		if (count < request_len)
		{
			break; /*EOF*/
		}
		if (!(++refresh_cycles & 0x1F))
		{
			const clock_t clk_now = clock();
			if ((clk_now < clk_update) || (clk_now - clk_update > UPDATE_INTERVAL))
			{
				FPRINTF(stderr, T("\b\b\b\b\b\b\b%5.1f%% "), (bytes_read / ((double)read_limit)) * 100.0);
				fflush(stderr);
				clk_update = clk_now;
			}
		}
	}

	if (ferror(file_in))
	{
		FPUTS(T("\n\nI/O error: Failed to read input data!\n\n"), stderr);
		goto clean_up;
	}

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

	if (fread(buffer, sizeof(uint8_t), sizeof(uint64_t), file_in) < sizeof(uint64_t))
	{
		FPUTS(T("\n\nI/O error: Failed to read final block!\n\n"), stderr);
		goto clean_up;
	}

	if ((status = slunkcrypt_inplace(ctx, buffer, sizeof(uint64_t))) != SLUNKCRYPT_SUCCESS)
	{
		FPUTS((status == SLUNKCRYPT_ABORTED) ? T("\n\nProcess interrupted!\n\n") : T("\n\nSlunkCrypt error: Failed to decrypt data!\n\n"), stderr);
		goto  clean_up;
	}

	const size_t padding = GET_LOWBITS(buffer[sizeof(uint64_t) - 1U]) + 1U;
	assert(padding && (padding <= sizeof(uint64_t)));
	if (padding != sizeof(uint64_t))
	{
		const size_t count = sizeof(uint64_t) - padding;
		if (fwrite(buffer, sizeof(uint8_t), count, file_out) < count)
		{
			FPUTS(T("failed!\n\nI/O error: Failed to write decrypted data!\n\n"), stderr);
			goto clean_up;
		}
		blake2s_update(&blake2s_state, buffer, count);
	}

	const uint64_t checksum_actual = blake2s_final(&blake2s_state);

	uint8_t checksum_buffer[sizeof(uint64_t)];
	if (fread(checksum_buffer, sizeof(uint8_t), sizeof(uint64_t), file_in) < sizeof(uint64_t))
	{
		FPUTS(T("\n\nI/O error: Failed to read the checksum!\n\n"), stderr);
		goto clean_up;
	}

	if ((status = slunkcrypt_inplace(ctx, checksum_buffer, sizeof(uint64_t))) != SLUNKCRYPT_SUCCESS)
	{
		FPUTS((status == SLUNKCRYPT_ABORTED) ? T("\n\nProcess interrupted!\n\n") : T("\n\nSlunkCrypt error: Failed to decrypt checksum!\n\n"), stderr);
		goto clean_up;
	}

	FPRINTF(stderr, T("\b\b\b\b\b\b\b%5.1f%%\n\n"), 100.0);
	fflush(stderr);

	const uint64_t checksum_stored = load_ui64(checksum_buffer);
	if (checksum_actual != checksum_stored)
	{
		FPRINTF(stderr, T("Error: Checksum mismatch detected! [expected: 0x%016") T(PRIX64) T(", actual: 0x%016") T(PRIX64) T("]\n\n"), checksum_stored, checksum_actual);
		FPUTS(T("Wrong passphrase or corrupted file?\n\n"), stderr);
		goto clean_up;
	}

	result = EXIT_SUCCESS;

	FPUTS(T("Checksum is correct.\n\n"), stderr);
	fflush(stderr);

clean_up:

	if (ctx)
	{
		slunkcrypt_free(ctx);
	}

	if (file_out)
	{
		fclose(file_out);
		if ((result != EXIT_SUCCESS) && remove_incomplete_files())
		{
			if (REMOVE(output_path))
			{
				FPUTS(T("Warning: Failed to remove incomplete output file!\n\n"), stderr);
			}
		}
	}

	if (file_in)
	{
		fclose(file_in);
	}

	slunkcrypt_bzero(buffer, BUFFER_SIZE);
	slunkcrypt_bzero(checksum_buffer, sizeof(uint64_t));
	slunkcrypt_bzero(&blake2s_state, sizeof(blake2s_t));
	slunkcrypt_bzero(&nonce, sizeof(uint64_t));
	slunkcrypt_bzero((void*)&checksum_stored, sizeof(uint64_t));
	slunkcrypt_bzero((void*)&checksum_actual, sizeof(uint64_t));

	return result;
}

// ==========================================================================
// Self-test
// ==========================================================================

static int run_test_case(const char *const message, const uint64_t nonce, const uint64_t checksum_message, const uint64_t checksum_expected)
{
	static const char* const TEST_PASSPHRASE = "OrpheanBeh0lderScry!Doubt";

	int status, result = EXIT_FAILURE;
	const size_t length = strlen(message) + 1U;
	slunkcrypt_t ctx = SLUNKCRYPT_NULL;

	char* const text_temp = strdup(message);
	if (!text_temp)
	{
		FPUTS(T("\n\nWhoops: Failed to allocate text buffer!\n\n"), stderr);
		goto clean_up;
	}

	const uint64_t checksum_original = blake2s_compute((uint8_t*)text_temp, length);
	if (checksum_original != checksum_message)
	{
		FPRINTF(stderr, T("\n\nWhoops: Checksum mismatch detected! [expected: 0x%016") T(PRIX64) T(", actual: 0x%016") T(PRIX64) T("]\n\n"), checksum_message, checksum_original);
		goto clean_up;
	}

	ctx = slunkcrypt_alloc(nonce, (const uint8_t*)TEST_PASSPHRASE, strlen(TEST_PASSPHRASE), SLUNKCRYPT_ENCRYPT);
	if (!ctx)
	{
		FPUTS(g_slunkcrypt_abort_flag ? T("\n\nProcess interrupted!\n\n") : T("\n\nWhoops: Failed to initialize encoder!\n\n"), stderr);
		goto clean_up;
	}

	status = slunkcrypt_inplace(ctx, (uint8_t*)text_temp, length);
	if (status != SLUNKCRYPT_SUCCESS)
	{
		FPUTS((status == SLUNKCRYPT_ABORTED) ? T("\n\nProcess interrupted!\n\n") : T("\n\nWhoops: Failed to encrypt the message!\n\n"), stderr);
		goto clean_up;
	}

	if (strncmp(message, text_temp, length) == 0)
	{
		FPUTS(T("\n\nWhoops: Encrypted message equals the original message!\n\n"), stderr);
		goto clean_up;
	}

	const uint64_t checksum_encrypted = blake2s_compute((uint8_t*)text_temp, length);
	if (checksum_encrypted != checksum_expected)
	{
		FPRINTF(stderr, T("\n\nWhoops: Checksum mismatch detected! [expected: 0x%016") T(PRIX64) T(", actual: 0x%016") T(PRIX64) T("]\n\n"), checksum_expected, checksum_encrypted);
		goto clean_up;
	}

	status = slunkcrypt_reset(ctx, nonce, (const uint8_t*)TEST_PASSPHRASE, strlen(TEST_PASSPHRASE), SLUNKCRYPT_DECRYPT);
	if (status != SLUNKCRYPT_SUCCESS)
	{
		FPUTS((status == SLUNKCRYPT_ABORTED) ? T("\n\nProcess interrupted!\n\n") : T("\n\nWhoops: Failed to initialize decoder!\n\n"), stderr);
		goto clean_up;
	}

	status = slunkcrypt_inplace(ctx, (uint8_t*)text_temp, length);
	if (status != SLUNKCRYPT_SUCCESS)
	{
		FPUTS((status == SLUNKCRYPT_ABORTED) ? T("\n\nProcess interrupted!\n\n") : T("\n\nWhoops: Failed to decrypt the message!\n\n"), stderr);
		goto clean_up;
	}

	if (memcmp(message, text_temp, length * sizeof(char)) != 0)
	{
		FPUTS(T("\n\nWhoops: Decrypted message does *not* match the original message!\n\n"), stderr);
		goto clean_up;
	}

	const uint64_t checksum_decrypted = blake2s_compute((uint8_t*)text_temp, length);
	if (checksum_decrypted != checksum_original)
	{
		FPRINTF(stderr, T("\n\nWhoops: Checksum mismatch detected! [expected: 0x%016") T(PRIX64) T(", actual: 0x%016") T(PRIX64) T("]\n\n"), checksum_original, checksum_decrypted);
		goto clean_up;
	}

	result = EXIT_SUCCESS;

clean_up:

	if (ctx)
	{
		slunkcrypt_free(ctx);
	}

	if (text_temp)
	{
		slunkcrypt_bzero(text_temp, strlen(text_temp));
		free(text_temp);
	}

	return result;
}

static int run_self_test(void)
{
	static const uint64_t TEST_NONCE[] = { 0x243F6A8885A308D3, 0x13198A2E03707344 };
	const struct
	{
		const char* text;
		uint64_t check_orig, check_encr[2U];
	}
	TEST_STAGE[] =
	{
		{ TEST_DATA_0, TEST_CHCK_ORIG_0, { TEST_CHCK_ENCR_0[0U], TEST_CHCK_ENCR_0[1U] } },
		{ TEST_DATA_1, TEST_CHCK_ORIG_1, { TEST_CHCK_ENCR_1[0U], TEST_CHCK_ENCR_1[1U] } },
		{ TEST_DATA_2, TEST_CHCK_ORIG_2, { TEST_CHCK_ENCR_2[0U], TEST_CHCK_ENCR_2[1U] } },
		{ TEST_DATA_3, TEST_CHCK_ORIG_3, { TEST_CHCK_ENCR_3[0U], TEST_CHCK_ENCR_3[1U] } },
	};

	const size_t total = ARRAY_SIZE(TEST_NONCE) * ARRAY_SIZE(TEST_STAGE);
	FPRINTF(stderr, T("Self-test is in progress, please be patient... stage %u/%u "), 0U, (unsigned)total);
	fflush(stderr);

	for (size_t i = 0U, count = 0U; i < ARRAY_SIZE(TEST_STAGE); ++i)
	{
		for (size_t j = 0U; j < ARRAY_SIZE(TEST_NONCE); ++j)
		{
			FPRINTF(stderr, T("\b\b\b\b%u/%u "), (unsigned)++count, (unsigned)total);
			fflush(stderr);
			if (run_test_case(TEST_STAGE[i].text, TEST_NONCE[j], TEST_STAGE[i].check_orig, TEST_STAGE[i].check_encr[j]) != EXIT_SUCCESS)
			{
				return EXIT_FAILURE;
			}
		}
	}

	FPRINTF(stderr, T("\b\b\b\b%u/%u\n\nCompleted successfully.\n\n"), (unsigned)total, (unsigned)total);
	fflush(stderr);

	return EXIT_SUCCESS;
}

// ==========================================================================
// Main function
// ==========================================================================

int MAIN(const int argc, CHR *const argv[])
{
	init_terminal();
	setup_signal_handler(SIGINT, sigint_handler);
	int result = EXIT_FAILURE;
	char *passphrase_buffer = NULL;

	FPRINTF(stderr, T("SlunkCrypt Utility (%") T(PRIstr) T("-%") T(PRIstr) T("), by LoRd_MuldeR <MuldeR2@GMX.de>\n"), OS_TYPE, CPU_ARCH);
	FPRINTF(stderr, T("Using libSlunkCrypt v%u.%u.%u [%") T(PRIstr) T("]\n\n"), SLUNKCRYPT_VERSION_MAJOR, SLUNKCRYPT_VERSION_MINOR, SLUNKCRYPT_VERSION_PATCH, SLUNKCRYPT_BUILD);

	/* ----------------------------------------------------- */
	/* Parse arguments                                       */
	/* ----------------------------------------------------- */

	if (argc < 2)
	{
		FPRINTF(stderr, T("Error: Nothing to do. Please type '%") T(PRISTR) T(" --help' for details!\n\n"), get_file_name(argv[0U]));
		goto clean_up;
	}

	const int slunk_mode = parse_slunk_mode(argv[1U]);
	switch (slunk_mode)
	{
	case MODE_HELP:
		print_manpage(get_file_name(argv[0U]));
	case MODE_VERS:
		result = EXIT_SUCCESS;
		goto clean_up;
	case MODE_ENCR:
	case MODE_DECR:
		break; /*fallthrough*/
	case MODE_PASS:
		result = generate_passphrase((argc > 2) ? STRTOUL(argv[2U]) : DFLT_PWDLEN_LENGTH);
		goto clean_up;
	case MODE_TEST:
		result = run_self_test();
		goto clean_up;
	default:
		FPRINTF(stderr, T("Error: The specified command \"%") T(PRISTR) T("\" is unknown!\n\n"), argv[1U]);
		goto clean_up;
	}

	if (argc < 4)
	{
		FPRINTF(stderr, T("Error: Required argument is missing. Please type '%") T(PRISTR) T(" --help' for details!\n\n"), get_file_name(argv[0U]));
		goto clean_up;
	}

	const CHR *const passphrase = PW_FROM_ENV ? GETENV(ENV_PASSWORD) : argv[2U];
	const CHR *const input_file = argv[PW_FROM_ENV ? 2U : 3U], *const output_file = argv[PW_FROM_ENV ? 3U : 4U];

	if ((!passphrase) || (!passphrase[0U]))
	{
		FPUTS(T("Error: The passphrase must be specified, directly or indirectly!\n\n"), stderr);
		goto clean_up;
	}

	if ((!PW_FROM_ENV) && STRICMP(passphrase, T("-")))
	{
		if ((!STARTS_WITH(passphrase, PREFIX_PASS)) && (!STARTS_WITH(passphrase, PREFIX_FILE)))
		{
			FPRINTF(stderr, T("Error: The passphrase must start with a '%") T(PRISTR) T("' or '%") T(PRISTR) T("' prefix!\n\n"), PREFIX_PASS, PREFIX_FILE);
			goto clean_up;
		}
	}

	if ((!input_file[0U]) || (!output_file[0U]))
	{
		FPUTS(T("Error: The input file and/or output file must not be empty!\n\n"), stderr);
		goto clean_up;
	}

	/* ----------------------------------------------------- */
	/* Initialize passphrase                                 */
	/* ----------------------------------------------------- */

	if (!(passphrase_buffer = PW_FROM_ENV ? copy_passphrase(passphrase) :
			(STARTS_WITH(passphrase, PREFIX_PASS) ? copy_passphrase(passphrase + STRLEN(PREFIX_PASS)) :
			(STARTS_WITH(passphrase, PREFIX_FILE) ? read_passphrase(passphrase + STRLEN(PREFIX_FILE)) : read_passphrase(T("-"))))))
	{
		goto clean_up;
	}

	slunkcrypt_bzero((CHR*)passphrase, STRLEN(passphrase) * sizeof(CHR));

	const size_t passphrase_len = strlen(passphrase_buffer);
	if (passphrase_len < SLUNKCRYPT_PWDLEN_MIN)
	{
		FPRINTF(stderr, T("Error: Passphrase must be at least %u characters in length!\n\n"), (unsigned)SLUNKCRYPT_PWDLEN_MIN);
		goto clean_up;
	}
	else if (passphrase_len > SLUNKCRYPT_PWDLEN_MAX)
	{
		FPRINTF(stderr, T("Error: Passphrase must be at most %u characters in length!\n\n"),  (unsigned)SLUNKCRYPT_PWDLEN_MAX);
		goto clean_up;
	}

	if (passphrase_len < RCMD_PWDLEN_LENGTH)
	{
		FPRINTF(stderr, T("Warning: Using a *short* passphrase; a length of %u characters or more is recommended!\n\n"), (unsigned)RCMD_PWDLEN_LENGTH);
	}
	else if (weak_passphrase(passphrase_buffer))
	{
		FPUTS(T("Warning: Using a *weak* passphrase; a mix of upper-case letters, lower-case letters, digits and 'special' characters is recommended!\n\n"), stderr);
	}

	/* ----------------------------------------------------- */
	/* Encrypt or decrypt                                    */
	/* ----------------------------------------------------- */

	const clock_t clk_start = clock();

	switch (slunk_mode)
	{
	case MODE_ENCR:
		result = encrypt(passphrase_buffer, input_file, output_file);
		break;
	case MODE_DECR:
		result = decrypt(passphrase_buffer, input_file, output_file);
		break;
	default:
		FPUTS(T("Unexpected mode encountered!\n\n"), stderr);
	}

	if (!g_slunkcrypt_abort_flag)
	{
		FPUTS(T("--------\n\n"), stderr);
		fflush(stderr);
		const clock_t clk_end = clock();
		FPRINTF(stderr, T("Operation completed after %.1f seconds.\n\n"), (clk_end - clk_start) / ((double)CLOCKS_PER_SEC));
	}

	/* ----------------------------------------------------- */
	/* Final clean-up                                        */
	/* ----------------------------------------------------- */

clean_up:
	
	if (passphrase_buffer)
	{
		slunkcrypt_bzero(passphrase_buffer, strlen(passphrase_buffer));
		free(passphrase_buffer);
	}

	return result;
}

#if defined(_WIN32) && defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR)
void __wgetmainargs(int*, wchar_t***, wchar_t***, int, int*);
int main()
{
	wchar_t** enpv, ** argv;
	int argc, si = 0;
	__wgetmainargs(&argc, &argv, &enpv, 1, &si);
	return wmain(argc, argv);
}
#endif