is there a shred-like command in linux for Ext3 filesystems? [Archive] - Glock Talk

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David_G17
07-19-2004, 14:23
i was looking at the shred man page, and noticed

The following are examples of filesystems on which shred
is not effective:

* log-structured or journaled filesystems, such as those supplied with

AIX and Solaris (and JFS, ReiserFS, XFS, Ext3, etc.)



i'm using Ext3. is there an alternative to shred that can do the same thing?

note: i'm not interested in wiping out my entire hard drive ;)

HerrGlock
07-19-2004, 15:40
Yeah "rm" is a whole like like shred. It's not all that easy to recover things even with standard rm on a *NIX system. It can be done and there are ways, but it's not that easy.

If you really want things gone, run this

dd if=/dev/random of=/bigfile bs=1024

for each of your mount points. / /usr/local /home, etc. When you start getting "no space left on device" errors, delete the file you created (/bigfile) and do it again.

DanH

David_G17
07-19-2004, 16:41
Originally posted by HerrGlock
Yeah "rm" is a whole like like shred.

oh, ok. i was afraid rm was like a standard windows delete (generally easily recoverable).

rm info page:
_Warning_: If you use `rm' to remove a file, it is usually possible to recover the contents of that file. If you want more assurance that the contents are truly unrecoverable, consider using `shred'.


are the linux guys who wrote the info page over-paranoid? is it much harder to recover files removed with rm than is implied?

HerrGlock
07-19-2004, 17:16
Originally posted by David_G17
are the linux guys who wrote the info page over-paranoid? is it much harder to recover files removed with rm than is implied?

It is possible. It's a whole lot easier in WIN, though. Use the dd command after you delete stuff if you want it overwritten and create a requirement for rather special stuff to undelete it.

DanH

HerrGlock
07-19-2004, 17:18
Originally posted by David_G17
are the linux guys who wrote the info page over-paranoid?

Linux guys in general are over-paranoid. It's one of the requirements of being interested in Linux ;f

DanH

David_G17
07-19-2004, 17:34
Originally posted by HerrGlock
Linux guys in general are over-paranoid. It's one of the requirements of being interested in Linux ;f

DanH

i've noticed. perhaps the MS guys could use a little more paranoia.;)

nothingness
07-19-2004, 18:41
look into gpg

David_G17
07-19-2004, 19:21
Originally posted by nothingness
look into gpg
neat!

anyone else interested may want to check out
http://www.aplawrence.com/Basics/gpg.html

nothingness
07-19-2004, 22:31
[*****@*****]$ kgpg --help Usage: kgpg [Qt-options] [KDE-options] [options] [File]

Kgpg - simple gui for gpg

Kgpg was designed to make gpg very easy to use.
I tried to make it as secure as possible.
Hope you enjoy it.

Generic options:
--help Show help about options
--help-qt Show Qt specific options
--help-kde Show KDE specific options
--help-all Show all options
--author Show author information
-v, --version Show version information
--license Show license information
-- End of options

Options:
-e Encrypt file
-k Open key manager
-s Show encrypted file
-S Sign file
-V Verify signature
-X Shred file

Arguments:
File File to open

physicsdevil
07-19-2004, 23:00
The reason that shred isn't effective on journaling filesystems is that it won't wipe the slack space (the unused space of any particular block on the disk). It's a relatively well known "hacker" trick to store files in slack space, making them difficult to detect. Included in the THC-SecureDelete package is a utility called sfill which will clean slack space. - http://www.thc.org/download.php?t=r&f=secure_delete-3.1.tar.gz