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Making erased files unrecoverable?

What is a good/free program that will wipe out deleted files so that they are never recoverable?

Would taking a file and copying it to the hard drive enough times so that the complete drive is full, then erasing it, would that do the trick?

I am using Windows 7.
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Jess31
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Jess31
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*** Hopeleonie ***IT ManagerCommented:
There are several tools.

For a whole hard drive we use:
DBAN ( www.dban.org )

For Partitions:
WipeDisk ( http://www.gaijin.at/dlwipedisk.php )

For Files & Data (also Partitions):
Eraser ( http://eraser.heidi.ie/download.php )
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Michael-BestCommented:
You can overwrite the data several times to make recovery impossible.
It is time consuming with free software.
Unless you can afford to wipe the whole drive...so I suggest Evidence Eliminator
http://download.cnet.com/Evidence-Eliminator/3000-2092_4-10206328.html

CCleaner may satisfy your needs?
http://www.piriform.com/ccleaner/download
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jcimarronCommented:
Jess31---The CNET page on Evidence Eliminator suggests it is not suitable for Win 7 or Vista. I do not know.
These articles may be of help
http://pcsupport.about.com/od/windows7/ht/format-hard-drive-windows-7.htm
(and DBAN is mentioned at the bottom).

http://gizmodo.com/5489933/leave-no-trace-how-to-completely-erase-your-hard-drives-ssds-and-thumb-drives
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XaelianCommented:
I would go for the eraser: http://eraser.heidi.ie/download.php here you can choose how many passes it must do. A 3 pass erase is really secure.
Or the cmd like program sdelete:
http://technet.microsoft.com/en-us/sysinternals/bb897443.aspx
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tliottaCommented:
Do you want to makes "files" unrecoverable, or do you want to clear an entire drive? Those are two very different things. Erasing a drive is generally easy, but "files" (without erasing the drive) is more difficult.

...so that the complete drive is full, then erasing it...

Yes, pretty much that would probably do it, so long as you're not trying to hide data from the NSA or similar very-high-tech organizations. There may be areas such as sectors that later became marked as bad that wouldn't be cleared, but it's not fully understood what you're needing to accomplish.

Tom
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Jess31Author Commented:
why would a one pass not be 100% effective?

And what about second part to the question:
Would taking a file and copying it to the hard drive enough times so that the complete drive is full, then erasing it, would that do the trick?
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XaelianCommented:
A one pass is good, but it's not 100% secure. Based on the guidelines a the US military Departement, a 3 way pass is the best there is. You can also do a 7 way pass, but that takes to long, and I don't see the advantage of this.

Your second part of the question. That would be ok. All the segments on the hard drive are overwritten then. So it's unreadable for data recovery programs.
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tliottaCommented:
A proper one-pass can be 100% effective. And filling a drive with a dummy file, then deleting the file would do the trick -- unless you need to meet truly high-security/military standards. (But there are much faster methods.)

Again, though, do you only want to remove certain files? Or do you want to clear a drive? Clearing a drive can be faster and easier.

Tom
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Jess31Author Commented:
Tom,

>>
Yes, pretty much that would probably do it, so long as you're not trying to hide data from the NSA or similar very-high-tech organizations. There may be areas such as sectors that later became marked as bad that wouldn't be cleared, but it's not fully understood what you're needing to accomplish.


But why would not one pass (or filling the drive with a tiff file and then erasing the tiff files) not be 100% even for NSA or anything?
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Adam LeinssCommented:
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XaelianCommented:
@aleinss
Already said sdelete.

@Jess31
http://en.wikipedia.org/wiki/Data_erasure here you get an overview who governments delete there data (how many passes). A 1 way pass is good, there are also instances, that just write in 1 big text file:
"010101010101010101010"

But what you want to do is good. You just need to make sure, that your HD is full with dummy data. And delete it, then nobody can retrieve your data (all the segments are overwritten).
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Adam LeinssCommented:
Oops, you did: my bad!
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*** Hopeleonie ***IT ManagerCommented:
@Xaelian
Already said Eraser :-)
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McKnifeCommented:
2 cents more: encrypt the drive. You won't have to worry about deletions (and temporary data) even if the drive dies.
[Of course if you have multiple admin users working on that drive (that can see the files of other users by default), then encryption is not enough and eraser is needed].
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tliottaCommented:
But why would not one pass (or filling the drive with a tiff file and then erasing the tiff files) not be 100% even for NSA or anything?

Review the Permanently delete data question for some basic links, just so it doesn't have to be typed again.

Beyond that...

Drives manufactured in this century (mostly; and probably in the 90's) have characteristics that make them different from those that were still commonly in use a decade or so ago. Things are changing. Tracks are narrower, "bits" are smaller, precision is greater. When an area is magnetized/demagnetized, it's more definite nowadays. Less bleeding into extra space and less residual magnetism. Tolerances are "very small".

There is some reason to think that very high capability organizations (e.g., NSA) with high quality equipment might be able to analyze disk surfaces. I'm not aware that it's ever actually been done.

That's the general thought behind the multi-pass cult that arose even though there's no evidence that it makes an actual difference for recovery. Or more likely, the evidence is that some military/government requirements call for multi-pass for secure cleaning. Whether those are meaningful or they're just standards based on "just in case" is questionable.

In any case, software solutions such as DBAN are unable to clean many/most drives fully no matter how many times they over-write. They can only access portions of drives that software can access. There are often areas that are marked by the drive as unusable, and software can't touch them.

For example, some sectors can be written to earlier in a drive's lifetime. Later, drive diagnostics might find faults in those sectors and mark them as 'bad'. All drives have spare sectors that can be activated in place of 'bad' sectors. Any data previously recorded in a 'bad' sector remains there for the rest of the drive's life. Accessing those areas (and one or two potential others) is only done by drive electronics.

Replacing the drive controller or related specialized procedures can allow reading any part of the drive that the read heads can be positioned over. It's not the kind of stuff that's done by just booting a program.

However, essentially every drive manufactured this century (generally ATA standards, >15GB capacity) has had a controller function called Secure Erase built in. (Link is for a utility that can activate the function. There are others.) It's not a trivial process, and probably should be practiced to learn the procedure. It is fast and it is reliable.

So, do you want to delete files? Or clear drives? If you're just deleting files, then delete them, defrag the drive and copy data to the drive until it's full and delete that. You're almost certainly fine. It'll take time and a little effort.

Tom
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