diff --git a/src/base64/ft_base64.c b/src/base64/ft_base64.c
index f9fdf404..9caa50a5 100644
--- a/src/base64/ft_base64.c
+++ b/src/base64/ft_base64.c
@@ -1,15 +1,36 @@
 #include <stdio.h>
 #include <sys/stat.h>
+#include <sys/stat.h>
 #include <fcntl.h>
 #include "libft.h"
 #include "ft_base64.h"
 
-static int	open_stream(char *filename, int flags, int mode)
+static int	open_input(char *filename)
 {
 	int fd;
-	if ((fd = open((const char *)filename, flags, mode)) == -1)
+	struct stat stat_buff;
+
+	if ((fd = open((const char *)filename, O_RDONLY, 0)) == -1)
 	{
-		perror("base64");
+		perror("base64: input stream error");
+		exit(1);
+	}
+	stat(filename, &stat_buff);
+	if (S_ISDIR(stat_buff.st_mode))
+	{
+		ft_putstr_fd("base64: input path is not a file", STDERR_FILENO);
+		exit(1);
+	}
+	return fd;
+}
+
+static int	open_output(char *filename)
+{
+	int fd;
+	if ((fd = open((const char *)filename,
+		O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR)) == -1)
+	{
+		perror("base64: output stream error");
 		exit(1);
 	}
 	return fd;
@@ -42,10 +63,9 @@ static void read_args
 		else if (ft_strcmp(current_arg, "-e") == 0 && ++i)
 			continue;
 		else if (ft_strcmp(current_arg, "-i") == 0)
-			ctx->input_fd = open_stream(next_arg, O_RDONLY, 0);
+			ctx->input_fd = open_input(next_arg);
 		else if (ft_strcmp(current_arg, "-o") == 0)
-			ctx->output_fd = open_stream(next_arg, O_CREAT | O_WRONLY,
-			S_IRUSR | S_IWUSR);
+			ctx->output_fd = open_output(next_arg);
 		else if (++i)
 			continue;
 		i++;
diff --git a/src/base64/ft_base64_decode_finish.c b/src/base64/ft_base64_decode_finish.c
index 7b352c2b..241fd6cc 100644
--- a/src/base64/ft_base64_decode_finish.c
+++ b/src/base64/ft_base64_decode_finish.c
@@ -1,3 +1,4 @@
+#include <fcntl.h>
 #include "ft_base64.h"
 #include "libft.h"
 
@@ -13,8 +14,8 @@ void		ft_base64_decode_finish
 		return ;
 	if (buffer_index != 0)
 	{
-		ft_putstr("\nbase64: invalid input: readed \
-bytes count isn't multiple of 4\n");
+		ft_putstr_fd("\nbase64: invalid input: readed \
+bytes count isn't multiple of 4\n", STDERR_FILENO);
 		exit(1);
 	}
 }
\ No newline at end of file
diff --git a/src/des/ft_des_arg_parsers.c b/src/des/ft_des_arg_parsers.c
index 1d322b6c..b549c627 100644
--- a/src/des/ft_des_arg_parsers.c
+++ b/src/des/ft_des_arg_parsers.c
@@ -1,5 +1,9 @@
-#include "ft_des.h"
 #include <stddef.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include "ft_des.h"
 
 int	ft_des_base64_arg_parser
 (
@@ -58,6 +62,48 @@ int ft_des_encode_arg_parser
 {
 	(void)argc;
 	(void)argv;
-	ctx->encode = 1;
+	ctx->decode = 0;
 	return (++position);
 }
+
+int ft_des_input_file_arg_parser
+(
+	int argc,
+	char **argv,
+	int position,
+	t_des_ctx *ctx
+)
+{
+	struct stat stat_buff;
+
+	if (position + 1 >= argc)
+		ft_des_print_error("there is no filaname after -i flag.");
+	if ((ctx->input_fd = open(argv[position + 1], O_RDONLY, 0)) == -1)
+	{
+		perror("des");
+		exit(1);
+	}
+	stat(argv[position + 1], &stat_buff);
+	if (S_ISDIR(stat_buff.st_mode))
+		ft_des_print_error("input path is not a file.");
+	return (position + 2);
+}
+
+int ft_des_output_file_arg_parser
+(
+	int argc,
+	char **argv,
+	int position,
+	t_des_ctx *ctx
+)
+{
+	if (position + 1 >= argc)
+		ft_des_print_error("there is no filaname after -o flag.");
+	if ((ctx->output_fd = open(
+		argv[position + 1], O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR)) == -1)
+	{
+		perror("des");
+		exit(1);
+	}
+	return (position + 2);
+}
diff --git a/src/des/ft_des_ecb.c b/src/des/ft_des_ecb.c
index a576e3fe..2eb2a858 100644
--- a/src/des/ft_des_ecb.c
+++ b/src/des/ft_des_ecb.c
@@ -18,6 +18,14 @@ t_des_argument_parser	g_arg_parsers[] = {
 		"-a",
 		ft_des_base64_arg_parser,
 	},
+	{
+		"-i",
+		ft_des_input_file_arg_parser,
+	},
+	{
+		"-o",
+		ft_des_output_file_arg_parser,
+	},
 	{ NULL, NULL},
 };