Slightly OT : Disk wiping?

  • Thread starter Thread starter Grendel
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G

Grendel

Hi,

As my hard drive has to go back, has anyone got any recommendations for any
good, free, disk wiping software? I don't want anyone seeing some of the
data that I've got.

Thanks,

Grendel.
 
BruceM said:
Won't be worth sending back if you use that!!!!!!!!!
Click to expand...

It says it shouldn't do any physical damage, but it might do. It's got a
*lot* of bad sectors anyway after just a few weeks, so I don't think it will
really make any difference.
 
Grendel said:
It says it shouldn't do any physical damage, but it might do. It's got a
*lot* of bad sectors anyway after just a few weeks, so I don't think it
will really make any difference.
Click to expand...
Except you could end up sending it back with a different fault to the one
you reported to get the RMA.

SteveH
 
Hi,

As my hard drive has to go back, has anyone got any recommendations for any
good, free, disk wiping software? I don't want anyone seeing some of the
data that I've got.

Thanks,

Grendel.
Click to expand...

This is the best one to use. It has a number of wipe methods you can
use. Depending on the size of your drive it can take a long time too.
The Guttman wipe method overwrites the drive 35 times and takes a very
long time. If you just want to write zeros to the drive (low level
format) it is fairly quick.

http://dban.sourceforge.net/
 
Actually, there are few ways of truly wiping data:
o When a HD head records data it does so by following a servo track
---- following the track results in data being recorded to the side
o Data is recorded as a probability distribution around the servo track
---- it is admittedly a very tight distribution, but it is one none the less
o An edge of layers of dated data remain distant from the servo track
---- over-wiping in theory reduces that incrementally

The problem is in theory isn't necessarily in practice:
o Mil spec wiping requires as I recall 4 overwrites
---- so diminishing such edge data to an unrecoverable level
o Overwriting also requires attention to the pattern used
---- otherwise it is possible to predict what was there
---- reverse-ECC, signal level & other tricks counters that

Remember a HD is an analog device - not digital - in recording.
Yes the signal is 1s & 0s, but analog techniques can interpret what
data was there before based on its particular value re 0.83 v 0.85 etc.

The reality comes down to security level required:
o NSA can pull your platters & use lots of tricks to get data back
o For basic financial, email etc data a decent program will suffice :-)

The most critical military/gov't uses a different method:
o Either a belt sander to remove the physical magnetic media
---- platters once aluminium are now glass in most instances
o Alternatively they just melt them down
---- probably more economic in terms of labour

Wiping data is an important consideration:
o MS-IE / XP regularly store auto-complete info for passwords
---- auto-complete on email address, get from ISP/Outlook settings
o Take someone's HD and you can access all financial info
---- transferring funds, pensions, bank contents
---- expenditure on credit cards, debit cards

At present identity theft is easier via your dustbin in the street,
but a stolen laptop owned by a financial adviser is a potential risk.
USA tends to have more problem with advisers bunking with money,
which overshadows that done more legally by CEOs & Wall Street :-)

For critical applications it is worth keeping a spare original HD, a
fully as-delivered-drive-O/S ready to go. That way if a laptop or PC
has to be sent for repair that can be enclosed with it, and also very
useful if your machine keels over (particularly if a laptop). It is then
just a matter of re-installing kep apps, your ISP settings & your data.
 
Actually, there are few ways of truly wiping data:
Click to expand...

Unless the person/organization wants to spend megabucks to try and
retrieve the data using microscopy. And I mean megabucks! The Dban
prog I provided the link to has a number of ways to wipe data and a
couple of them are quite secure but very timely. If data is so easily
to retrieve then explain to me how come the NSA, or whoever. still
hasn't been able to retreive the voice recordings of President Nixon
on the tapes from the watergate scandal that had parts erased? They
were just analog tapes erased once and yet those erased parts of the
tapes have never been recovered. although, they have tried supposedly.
If the government is so clever with data retrieval why is that?

If you just want to stop the avarage joe from ever seeing your data a
quick pseudo random data wipe will do it.
 
Actually, there are few ways of truly wiping data:
o When a HD head records data it does so by following a servo track
---- following the track results in data being recorded to the side
o Data is recorded as a probability distribution around the servo track
---- it is admittedly a very tight distribution, but it is one none the less
o An edge of layers of dated data remain distant from the servo track
---- over-wiping in theory reduces that incrementally
Click to expand...

When you wipe a drive the *whole* drive is wiped. Many times! Download
Dban and do some reading on the various methods.
 
I wouldn't bring as an example a 'politically motivated' scenario, nothing
is as it should be in that context.
Why are we still driving cars that burn fossil fuels?
 
When you wipe a drive the *whole* drive is wiped.
Many times! Download Dban and do some reading
on the various methods.
Click to expand...

Hence my comment:
"For basic financial, email etc data a decent program will suffice :-)"

My comment was about the way in which HD data is actually
recorded itself allows various methods of data recovery.

Whilst the forensic capability exists - I doubt it is much used:
o Military will use it on Osama's disks
---- such data is of high value re 1) primary-source & 2) available
---- typical intelligence officer in M.E. sticks out like a sore thumb
o Forensics will rarely need t use it
---- typical paedophile profile is they never destroy their last copy
---- so for them it is a matter of physical finding HD (vs wiped recovery)
---- indeed more likely is they work back from subscription data

So again, a decent program will suffice.
It simply does not mean the data is "absolutely undetectable",
for practical purposes it does - indeed for RMA purposes too :-)

Military just wipe data 4 times to some specified pattern IIRC.
So a simple data wipe is good enough for them in most cases.

However speed could be an issue with 400GB drives :-)
 
JAD said:
I wouldn't bring as an example a 'politically motivated' scenario, nothing
is as it should be in that context.
Why are we still driving cars that burn fossil fuels?
Click to expand...

Because, so far, nothing else works as well for the price.
 
Aldwyn said:
Unless the person/organization wants to spend megabucks to try and
retrieve the data using microscopy. And I mean megabucks! The Dban
prog I provided the link to has a number of ways to wipe data and a
couple of them are quite secure but very timely. If data is so easily
to retrieve
Click to expand...

No one said it was 'easy'.
then explain to me how come the NSA, or whoever. still
hasn't been able to retreive the voice recordings of President Nixon
on the tapes from the watergate scandal that had parts erased? They
were just analog tapes erased once and yet those erased parts of the
tapes have never been recovered. although, they have tried supposedly.
If the government is so clever with data retrieval why is that?
Click to expand...

The short answer is that audio tape is not a hard drive and there's almost
no similarity other than being a "magnetic recording" of some type.

Digital recording is a magnetic domain change and is either 1 or 0. Analog
is a continuously varying signal with undefined volume levels. Put simply,
it's a heck of a lot easier to distinguish a polarity switch than it is to
recover analog. (same reason DTV is 'better' than analog. As long as you
can detect the 1s and 0s the picture is 'perfect' regardless of the ambient
noise while analog TV becomes distorted and indecipherable.)

And then there are the physical differences. Disk magnetic material is not
the same as that used for analog tape. And a hard drive uses the same head
to both read and write, which means the read/write track width is identical
so that any variation in alignment, as there always is, can leave a
residual. Tape machines, on the other hand, usually have multiple heads,
depending on how good a unit it is, and, in particular, often have a
separate erase head (cheap units just slap a bar magnet against the tape).
As such there is no inherent 'identical size' constraint to leave a
residual signal (although it might, again, depending on the unit, tape
bias, alignment, and a whole host of other factors).
 
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