Provided by: secure-delete_3.1-5_i386 bug

NAME

       sfill  -  secure  free  disk  and  inode  space  wiper (secure_deletion
       toolkit)

SYNOPSIS

       sfill [-f] [-i] [-I] [-l] [-l] [-v] [-z] directory/mountpoint

DESCRIPTION

       sfill is designed to delete data which lies on available  diskspace  on
       mediums  in  a  secure manner which can not be recovered by thiefs, law
       enforcement or other threats.  The wipe algorythm is based on the paper
       "Secure   Deletion  of  Data  from  Magnetic  and  Solid-State  Memory"
       presented at the 6th Usenix Security Symposium by Peter Gutmann, one of
       the leading civilian cryptographers.

       The secure data deletion process of sfill goes like this:

       *      1 pass with 0xff

       *      5  random  passes.  /dev/urandom  is  used  for  a secure RNG if
              available.

       *      27 passes with special values defined by Peter Gutmann.

       *      5 random passes. /dev/urandom  is  used  for  a  secure  RNG  if
              available.

       afterwards  as  many  temporary files as possible are generated to wipe
       the free inode space. After no more temporary  files  can  be  created,
       they are removed and sfill is finnished.

COMMANDLINE OPTIONS

       -f     fast (and insecure mode): no /dev/urandom, no synchronize mode.

       -i     wipe only free inode space, not free disk space

       -I     wipe only free disk space, not free inode space

       -l     lessens the security. Only two passes are written: one mode with
              0xff and a final mode with random values.

       -l     -l for a second time lessons the security even  more:  only  one
              random pass is written.

       -v     verbose mode

       -z     wipes the last write with zeros instead of random data

       directory/mountpoint  this  is the location of the file created in your
       filesystem. It should lie on the partition you want to write.

LIMITATIONS

       FILESYSTEM INTELLIGENCE
              Most  filesystems  (ext2,  ffs,  etc.)  have  several   features
              included to enhance performance, which will result in that sfill
              might not receive  all  available  free  space.  Sad  but  true.
              Nothing can be done about that ...

       NFS    Beware of NFS. You can't ensure you really completely wiped your
              data from the remote disks. (especially because of caching)

       Raid   Raid Systems use stripped disks and have got large caches.  It's
              hard to wipe them.

       swap   Some of your data might have a copy in your swapspace.  sswap is
              available for this task.

BUGS

       No bugs. There was never a  bug  in  the  secure_deletion  package  (in
       contrast  to  my  other tools, whew, good luck ;-) Send me any that you
       find.  Patches are nice too :)

AUTHOR

       van Hauser / THC <vh@thc.org>

DISTRIBUTION

       The newest version of the secure_deletion package can be obtained  from
       http://www.thc.org

       sfill  and the secure_deletion package is (C) 1997-2003 by van Hauser /
       THC (vh@thc.org)

       This program 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; Version 2.

       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.

SEE ALSO

       srm (1), sswap (1), sdmem (1)

                                                                      SFILL(1)