SHRED for EXT3?

Scot L. Harris webid at cfl.rr.com
Tue Jul 26 17:41:51 UTC 2005


On Tue, 2005-07-26 at 13:09, Laurence wrote:
> On Tue, 2005-07-26 at 08:09 -0600, Robin Laing wrote:
> > Mike McCarty wrote:
> > > Is there a secure file delete available for ext3 file systems?
> > > 
> > > Mike
> > 
> > Possibly encrypt the data in the first place?
> > 
> > http://www.linuxjournal.com/article/6481
> > 
> > -- 
> > Robin Laing
> > 
> 
> how about opening the file & writing zeros to it?

I don't remember the specs but there are specifications published by the
U.S. Government for what constitutes secure deletion of files from
magnetic media.  This requires a certain number of rewrites over the
same sectors the file was in and I think a specific set of patterns.  

Over writing a file once is usually not sufficient.  There are residual
traces of what was written to the drive that with the right tools can be
recovered in some cases.

Of course if you are disposing of a hard drive the only secure method of
disposal is to take a hammer to it.  A few years ago a study was
conducted where they bought used hard drives from ebay.  A variety of
recovery methods were used and the researchers were able to recover a
wide variety of personal information including SSNs, credit cards, etc.
on a significant number of the drives purchased.


-- 
Scot L. Harris
webid at cfl.rr.com

No matter what happens, there is always someone who knew it would. 




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