Sure delete

  • Thread starter Thread starter il barbi
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il barbi

I'm using this good utility to definitely erase the free space of my HD. Now
I'd like to ask 2 questions:
1) I'm sure the free space of my HD is unrecoverable, but do existing files
keep any track of the former data recorded in their physical sectors?
Namely, before I ran Sure Delete the free sectors were currently re-used to
record new or modified files, so perhaps they have been recorded only 1,2 or
3 times and so some highlevel recovery utility would be able to recover
their previous content. I guess there would need an utility "normalising"
the voltage level of o's and 1's in existing files in order to definitely
cancel the previous content - maybe this utility exists? Perhaps I could do
this way: I could copy each file and then erase it by Sure Delete, indeed
this is very time consuming but I think it could work. Or perhaps I could
record an iso imagine of my HD, then format and restore it? Does formatting
cancel any track of the previous content?
2) Does anyone know how to run Sure Delete from a line command, by
specifying file(s) to be deleted and number of passes?
TIA
il barbi
 
il said:
I'm using this good utility to definitely erase the free space of my HD. Now
I'd like to ask 2 questions:
1) I'm sure the free space of my HD is unrecoverable, but do existing files
keep any track of the former data recorded in their physical sectors?
Namely, before I ran Sure Delete the free sectors were currently re-used to
record new or modified files, so perhaps they have been recorded only 1,2 or
3 times and so some highlevel recovery utility would be able to recover
their previous content. I guess there would need an utility "normalising"
the voltage level of o's and 1's in existing files in order to definitely
cancel the previous content - maybe this utility exists? Perhaps I could do
this way: I could copy each file and then erase it by Sure Delete, indeed
this is very time consuming but I think it could work. Or perhaps I could
record an iso imagine of my HD, then format and restore it? Does formatting
cancel any track of the previous content?
2) Does anyone know how to run Sure Delete from a line command, by
specifying file(s) to be deleted and number of passes?
Click to expand...

I don't know about command line options for Sure Delete but I can assure
you that no one has ever been able to recover files on a securely wiped
drive.

John
 
The files can be recovered by professional recovery people even if you use Sure
Delete. Ask any law enforcement or intelligence agency. The only way you can get rid
of your files on the hard Disk permanently is to destroy the disk physically
 
John said:
Citations please.

Can be filed under "Urban Myths.

John
Click to expand...

The answer differs over the various generations of disks. Modern
drives have switched to perpendicular recording, and many aspects
of the design have changed. The effectiveness of MFM changes with
them.

For a comment on data recovery of erased modern drives, see this article.

http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html

"Any modern drive will most likely be a hopeless task, what
with ultra-high densities and use of perpendicular recording
I don't see how MFM would even get a usable image, and then
the use of EPRML will mean that even if you could magically
transfer some sort of image into a file, the ability to decode
that to recover the original data would be quite challenging.
OTOH if you're going to use the mid-90s technology that I
talked about, low-density MFM or (1,7) RLL, you could do it
with the right equipment, but why bother? Others have already
done it, and even if you reproduced it, you'd just have done
something with technology that hasn't been used for ten years.
This is why I've never updated my paper (I've had a number of
requests), there doesn't seem to be much more to be said about
the topic."

(MFM is Magnetic Force Microscopy)

So the only place you'll see data recovered on an erased
modern 1TB hard drive, is on the CSI TV series. And it only
takes them 30 seconds to do it :-)

Paul
 
Peter said:
The files can be recovered by professional recovery people even if you
use Sure Delete. Ask any law enforcement or intelligence agency. The
only way you can get rid of your files on the hard Disk permanently is
to destroy the disk physically
Click to expand...

Citations please.

Can be filed under "Urban Myths.

John
 
Paul said:
The answer differs over the various generations of disks. Modern
drives have switched to perpendicular recording, and many aspects
of the design have changed. The effectiveness of MFM changes with
them.

For a comment on data recovery of erased modern drives, see this article.

http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html
Click to expand...

Yes, I have seen and read that. I have had an email conversation with
Dr. Gutmann and he has told me that he was never able to recover data
with the method that he had advanced, even on these old drives he
couldn't do it. His research was completely misinterpreted by some who
then ran with it and proclaimed that data recovery was possible on
overwritten drives. It just never happened, and the purpose of his
paper was not to develop a data recovery method but to securely erase
data and foil any data recovery attempts, read in his epilogue:

"Another point that a number of readers seem to have missed is that this
paper doesn't present a data-recovery solution but a data-deletion
solution. In other words it points out in its problem statement that
there is a potential risk, and then the body of the paper explores the
means of mitigating that risk."

He himself has never been able to recover data using the theoretical
"potential risk" that he advanced and nobody else was ever able to do it.

Reading Charles H Sobeys's paper will put some of the misconceptions to
rest:

Recovering Unrecoverable Data - The Need for Drive-Independant Data Recovery
http://www.actionfront.com/ts_whitepaper.aspx

So the only place you'll see data recovered on an erased
modern 1TB hard drive, is on the CSI TV series. And it only
takes them 30 seconds to do it :-)
Click to expand...

Indeed, it all falls in the realm of urban legends. Your CSI reference
is interesting, we have the same opinion. See one of my posts here:

http://groups.google.com/group/micr...support/msg/bf90b516a3ae3fd2?&q=audetweld+csi

John
 
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