diff --git a/src/file_tar.c b/src/file_tar.c
index 4d3a3567..7afc2449 100644
--- a/src/file_tar.c
+++ b/src/file_tar.c
@@ -3,17 +3,17 @@
     File: file_tar.c
 
     Copyright (C) 1998-2005,2007 Christophe GRENIER <grenier@cgsecurity.org>
-  
+
     This software 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 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; if not, write the Free Software Foundation, Inc., 51
     Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
@@ -27,6 +27,7 @@
 #include <string.h>
 #endif
 #include <stdio.h>
+#include <ctype.h>
 #include "types.h"
 #include "filegen.h"
 #include "file_tar.h"
@@ -43,25 +44,44 @@ const file_hint_t file_hint_tar= {
   .register_header_check=&register_header_check_tar
 };
 
-static const unsigned char tar_header_gnu[6]	= { 'u','s','t','a','r',0x00};
-static const unsigned char tar_header_posix[8]  = { 'u','s','t','a','r',' ',' ',0x00};
-
-static void register_header_check_tar(file_stat_t *file_stat)
-{
-  register_header_check(0x101, tar_header_gnu,sizeof(tar_header_gnu), &header_check_tar, file_stat);
-  register_header_check(0x101, tar_header_posix,sizeof(tar_header_posix), &header_check_tar, file_stat);
-}
+struct posix_header
+{				/* byte offset */
+  char name[100];		/*   0 */
+  char mode[8];			/* 100 */
+  char uid[8];			/* 108 */
+  char gid[8];			/* 116 */
+  char size[12];		/* 124 */
+  char mtime[12];		/* 136 */
+  char chksum[8];		/* 148 */
+  char typeflag;		/* 156 */
+  char linkname[100];		/* 157 */
+  char magic[6];		/* 257 */
+  char version[2];		/* 263 */
+  char uname[32];		/* 265 */
+  char gname[32];		/* 297 */
+  char devmajor[8];		/* 329 */
+  char devminor[8];		/* 337 */
+  char prefix[155];		/* 345 */
+				/* 500 */
+};
 
 int header_check_tar(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
 {
+  const struct posix_header *h=(const struct posix_header *)buffer;
   if(file_recovery->file_stat!=NULL && file_recovery->file_stat->file_hint==&file_hint_tar)
     return 0;
-  if(memcmp(&buffer[0x101],tar_header_gnu,sizeof(tar_header_gnu))==0 ||
-      memcmp(&buffer[0x101],tar_header_posix,sizeof(tar_header_posix))==0)
-  {
-    reset_file_recovery(file_recovery_new);
-    file_recovery_new->extension=file_hint_tar.extension;
-    return 1;
-  }
-  return 0;
+  if(!isspace(h->chksum[0]) && !((unsigned) (h->chksum[0]) - '0' <= 7))
+    return 0;
+  reset_file_recovery(file_recovery_new);
+  file_recovery_new->extension=file_hint_tar.extension;
+  file_recovery_new->min_filesize=512;
+  return 1;
+}
+
+static void register_header_check_tar(file_stat_t *file_stat)
+{
+  static const unsigned char tar_header_gnu[6]	= { 'u','s','t','a','r',0x00};
+  static const unsigned char tar_header_posix[8]  = { 'u','s','t','a','r',' ',' ',0x00};
+  register_header_check(0x101, tar_header_gnu,sizeof(tar_header_gnu), &header_check_tar, file_stat);
+  register_header_check(0x101, tar_header_posix,sizeof(tar_header_posix), &header_check_tar, file_stat);
 }