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General discussion

How can I SECURELY delete a previously deleted file?

by mortalmonkey Sep 20, 2007 8:59PM PDT

I've deleted a file in WinXP which I meant to securely delete. My
questions are:

1) Is there a secure file wipe utility that can find previously
deleted files (assuming they haven't been overwritten) and then
securely delete them? I know I can securely wipe free space but the
time involved in doing this means it is not an option.

2) Is there a file restore/recovery program that doesn't just restore
to another disk (i.e. copies the deleted file), but instead resets the
attributes of the deleted file, but doesn't in any way change or move
the original deleted file, so that it appears as normal in windows
again (from which I can then use a secure delete utility as normal)?

3) any other ways to securely delete a deleted but not overwritten
file?

I'll be very grateful for any help.

Discussion is locked

4 Posts
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I would search Google for "File recovery" software
by MarkFlax Forum moderator Sep 20, 2007 11:01PM PDT

Without the quotes.

Most will cost you but you may find some freeware software there.

Mark

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Re: wipe free space
by Kees Bakker Sep 21, 2007 4:39AM PDT

- How much free space do you have?
- How long would it take to wipe it? With what program?
- Why is that unacceptable? If it's important, why can't you let it run for a weekend?
- Assuming it's 100 Gb free, time how long a copy of a 1 Gb file takes. Say one minute. Then 100 copies take 100 minutes. Easy to do in a batch file. This overwrites all free space. Repeat with another 1 Gb file. That's another 100 minutes. Nobody will ever find your data. Explain why 200 minutes is unacceptable.
- A file of 500 Mb might be better, because the source can easily stay in 1 Gb RAM, so the copy only writes and doesn't read. Experiment a little bit.

Kees

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Secure wiping a deleted file
by mortalmonkey Sep 21, 2007 5:06AM PDT

Thanks for the reply Kees.

I need to wipe about ten 250k files and there is 480GB free space. I need to do a Guttman wipe and i estimate that a guttman on 480GB will take somewhere in the region of 20-30 days. So as I said, not acceptable. i just need to be able to recover those ten files (recover mind, not copy) and then securely delete them.

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Re: wiping a file
by Kees Bakker Sep 22, 2007 4:22AM PDT

Wow ... 35 passes, that certainly should do it. It's Gutmann, by the way, not Guttman. Read the article at http://www.cs.auckland.ac.nz/%7Epgut001/pubs/secure_del.html

In this case, I should do it the other way around. Buy a new hard disk (might be quite a lot of Gb smaller, if you've got so much free space), clone the contents of the old drive (free space isn't cloned) and physically destroy the old one. If it's about such a degree of security, who cares about USD 200 or so.

You might consider to find an old drive of a few Gb to store sensitive data. If anything like this happens again, it can be remedied in a reasonable time.

Hope this helps.


Kees

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