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Date:      Mon, 15 Dec 2003 13:55:07 -0600
From:      "Pratt, Benjamin E." <bepratt@stcloudstate.edu>
To:        "Chris Pressey" <cpressey@catseye.mine.nu>
Cc:        freebsd-questions@freebsd.org
Subject:   RE: Secure Deletion (Like shred for Linux)??
Message-ID:  <4F752E686C8E04449DCB9FA7C3BD9674718262@EXCHANGE.campus.stcloudstate.edu>
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[-- Attachment #1 --]
Chris -

It doesn't look like they do quite what I'd like.  Here's the man page
for shred (http://unixhelp.ed.ac.uk/CGI/man-cgi?shred+1).  Shred is used
in a shell script called Autoclave
(http://staff.washington.edu/jdlarios/autoclave/) to securely wipe a
hard drive before getting rid of it.  I've attached the "autoclave.sh"
script (as long as attachments are allowed, ask me for it if you don't
get the attachment).

Ben

-----Original Message-----
From: Chris Pressey [mailto:cpressey@catseye.mine.nu] 
Sent: Monday, December 15, 2003 1:50 PM
To: Pratt, Benjamin E.
Cc: freebsd-questions@freebsd.org
Subject: Re: Secure Deletion (Like shred for Linux)??

On Mon, 15 Dec 2003 13:31:52 -0600
"Pratt, Benjamin E." <bepratt@stcloudstate.edu> wrote:

> Hello -
> 
> I'm fairly new to FreeBSD and was wondering if there are any other
> programs out there for secure deletion.  I know that you can use the
> -P flag with rm to overwrite files but you can't specify the
> iterations of overwriting.
> 
> What I'm looking for is something similar to (or exactly like) shred
> for Linux.  Is it out there??
> 
> Thanks,
> 
> Ben

Hi,

The only programs I've seen like what you describe are 'obliterate' and
'srm'.

  /usr/ports/sysutils/obliterate
  /usr/ports/security/srm

I'm not sure either of them does exactly what you want (specifying how
many times to overwrite the file,) but they may be worth checking out.

-Chris

[-- Attachment #2 --]
#shred -x -v -n $PASSES /dev/$DEVICE

autoclave-03/
devs=`grep -H ide-disk /proc/ide/hd*/driver | cut -f 4 -d "/"`


echo "Drives found:"
echo

while [ "$flag" != "done" ]; do
    count=0
    for i in $devs; do
  let "count=$count+1"
  eval "dev$count=$i"

  echo "$count) $i"
  echo "-----------"
  cat /proc/ide/$i/model
  blocks=`cat /proc/ide/$i/capacity`
  bytes=`echo "$blocks 512 * p" | dc`
  eval "size$count=$bytes"
  echo "Size: $bytes bytes"
    done

    if [ $count -eq 0 ]; then
  echo "No drives found."
  exit
    fi


    echo -n "Please choose a drive (1-$count) for more information (Q to quit): "
    read choice
    case $choice in
  [Qq]*)
      echo "Stopping."
      exit
  ;;
  *)
      eval device=\$dev$choice
      eval bytes=\$size$choice
      if [ "$device" != "" ]; then
    flag="done"
      fi
  ;;
    esac
done

cmdline="shred -x -v"
# --size=$bytes

echo
echo "With what level of confidence would you like to erase this disk?"
echo
echo "1)  Zero disk only. Slow, only effective against non-hackers."
echo "2)  One random pass. A little slower, effective against most."
echo "3)  3 \"binary overwrite\" passes. Even slower, likely as secure as you need."
echo "4)  10 passes, some structured. Very slow. Almost certainly secure."
echo "5)  25 structured passes. Unbearably slow, but probably secure against the NSA."
echo

flag=""
while [ "$flag" != "done" ]; do
  echo -n "Level (1-5,Q)? "
  read level
  case $level in
    1)
  cmdline="$cmdline -n 0 -z"
  flag="done"
    ;;
    2)
  cmdline="$cmdline -n 1 -z"
  flag="done"
    ;;
    3)
  cmdline="$cmdline -n 3"
  flag="done"
    ;;
    4)
  cmdline="$cmdline -n 10 -z"
  flag="done"
    ;;
    5)
  flag="done"
    ;;
    [Qq]*)
  echo "Stopping."
  exit
    ;;
    *)
    ;;

    esac
done

cmdline="$cmdline /dev/$device"
echo "About to run the command: $cmdline"
echo "WARNING: THIS WILL COMPLETELY ERASE THE DISK /dev/$device."
flag=""

while [ "$flag" != "done" ]; do
echo -n "Are you absolutely sure you want to do this? (Y/N) "
read final
case $final in
  [Yy]*)
    flag="done"
    echo "Ok then. Don't say I didn't warn you."
    eval $cmdline
    echo
    echo "Finished erasing /dev/$device."
  ;;
  [Nn]*)
    flag="done"
    echo "Stopping."
    exit
  ;;
  *)
    echo "I'm looking for \"yes\" or \"no\" here."
  ;;
esac
done

echo "Done."

PATH=/usr/i386-linux-uclibc/bin/:$PATH gcc -D_FILE_OFFSET_BITS=64 -D__USE_FILE_OFFSET64 -O2 shred.c -o shred
strip shred
size shred
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