diff --git a/libntfs/security.c b/libntfs/security.c
index e69de29b..e1f4113e 100644
--- a/libntfs/security.c
+++ b/libntfs/security.c
@@ -0,0 +1,97 @@
+/*
+ * security.c - Code for handling security/ACLs in NTFS.  Part of the
+ *		Linux-NTFS project.
+ *
+ * Copyright (c) 2004 Anton Altaparmakov
+ *
+ * This program/include file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program/include file is distributed in the hope that it will be
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program (in the main directory of the Linux-NTFS
+ * distribution in the file COPYING); if not, write to the Free Software
+ * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include "types.h"
+#include "layout.h"
+#include "security.h"
+
+/*
+ * The zero GUID.
+ */
+static const GUID __zero_guid = { const_cpu_to_le32(0), const_cpu_to_le16(0),
+		const_cpu_to_le16(0), { 0, 0, 0, 0, 0, 0, 0, 0 } };
+const GUID *const zero_guid = &__zero_guid;
+
+/**
+ * ntfs_guid_is_zero - check if a GUID is zero
+ * @guid:	guid to check
+ *
+ * Return TRUE if @guid is a valid pointer to a GUID and it is the zero GUID
+ * and FALSE otherwise.
+ */
+BOOL ntfs_guid_is_zero(const GUID *guid)
+{
+	return (memcmp(guid, zero_guid, sizeof(*zero_guid)));
+}
+
+/**
+ * ntfs_guid_to_mbs - convert a GUID to a multi byte string
+ * @guid:	guid to convert
+ * @guid_str:	string in which to return the GUID (optional)
+ *
+ * Convert the GUID pointed to by @guid to a multi byte string of the form
+ * "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX".  Therefore, @guid_str (if not NULL)
+ * needs to be able to store at least 37 bytes.
+ *
+ * If @guid_str is not NULL it will contain the converted GUID on return.  If
+ * it is NULL a string will be allocated and this will be returned.  The caller
+ * is responsible for free()ing the string in that case.
+ *
+ * On success return the converted string and on failure return NULL with errno
+ * set to the error code.
+ */
+char *ntfs_guid_to_mbs(const GUID *guid, char *guid_str)
+{
+	char *_guid_str;
+	int res;
+
+	if (!guid) {
+		errno = EINVAL;
+		return (char *)guid;
+	}
+	_guid_str = guid_str;
+	if (!_guid_str) {
+		_guid_str = malloc(37);
+		if (!_guid_str)
+			return _guid_str;
+	}
+	res = snprintf(_guid_str, 37,
+			"%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+			le32_to_cpu(guid->data1),
+			le16_to_cpu(guid->data2), le16_to_cpu(guid->data3),
+			guid->data4[0], guid->data4[1],
+			guid->data4[2], guid->data4[3], guid->data4[4],
+			guid->data4[5], guid->data4[6], guid->data4[7]);
+	if (res == 36)
+	       return _guid_str;
+	if (!guid_str)
+		free(_guid_str);
+	errno = EINVAL;	
+	return NULL;
+}