Is it safe to sell a hard drive after I format it?

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NightCrawler

Diamond Member
Oct 15, 2003
3,179
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Originally posted by: n0cmonkey
Originally posted by: NightCrawler
Could use Safe Boot Solo to encrypt the entire disc and then do a low level format. Even if they could recover the data it would be encrypted. I doubt they could break through the encryption but who knows maybe there is a back door.
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How much will encrypting after the fact help? That data needed to be encrypted when it hit the disk.
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Don't think that is how it works, otherwise Safeboot Solo would be a useless product. If someone steals your laptop and it's encrypted with safeboot solo it's pretty safe that they won't be able to steal any of your information.

 
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n0cmonkey

Elite Member
Jun 10, 2001
42,936
1
0
Originally posted by: NightCrawler
Originally posted by: n0cmonkey
Originally posted by: NightCrawler
Could use Safe Boot Solo to encrypt the entire disc and then do a low level format. Even if they could recover the data it would be encrypted. I doubt they could break through the encryption but who knows maybe there is a back door.
Click to expand...

How much will encrypting after the fact help? That data needed to be encrypted when it hit the disk.
Click to expand...

Don't think that is how it works, otherwise Safeboot Solo would be a useless product. If someone steals your laptop and it's encrypted with safeboot solo it's pretty safe that they won't be able to steal any of your information.
Click to expand...

I'm really tired and feeling kind of dumb, so please forgive me if I am being dumb. Aren't we saying the same thing? That the data needed to be encrypted originally?

If you are going to over write the data afterwards, the only benefit the encryption would add is the randomness. The traces of the file are still there in whatever non-encrypted format they were originally.

EDIT: Yeah, safeboot solo looks like an encrypted disk solution. I don't think it is meant to be used after the fact, but to be used from when the files are created on-ward. Encrypting the file won't ensure that it is being over written.
 
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buleyb

Golden Member
Aug 12, 2002
1,301
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Originally posted by: Perplx
I think a single wipe all 0s or 1s is sufficient. If people could reliably find what data was on a wiped hardrive then hardrive capacity would double.
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The problem is reliably getting info. They aren't sold as having 7x the capacity listed, because its not an easy feat to read the residual fields, but that doesn't mean its not possible. Besides, to get some sensative data, you don't need the whole disk, just a few bytes of data.


regardless. If you are worried about people getting your info, do a 3-5 pass wipe of the drive (7 if you're uber paranoid), its easy enough to do, and would be done by now if you started it when you started this thread.

If its just personal info, its easier/cheaper for someone to trick that info out of you rather than fiddle with your hard drive.
 
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buleyb

Golden Member
Aug 12, 2002
1,301
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Originally posted by: sharq
You can run all of the erasing tools, but it won't help you much. The kind of scrubbing actually required will basically render the hard drive useless. I did some work on computer forensics and their tools for a senior level class, and the only 100% way, is to break the platters in the harddrive, but then you can't sell it. :)
Yes the tools to recover the data are not cheap, and you can't buy them from your local Compusa or Bestbuy, but if someone wanted your data (I emphasize the word "IF") then it's not out of their reach.
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I'll bite, you have proof of this? Links?

There is a lot of research done on wiping hard drives, and the consensus disagrees with you. Residual fields can be disrupted and weakened after a 7 wipe pass to the point where the detected field isn't gone, but the detection cannot get an accurate reading either way, making 0s and 1s too difficult to determine.

as for 'breaking the platters', the only true way to end the topic is to grind off the surfaces of the platters.
 
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nx02nx02

Senior member
Dec 26, 2001
539
0
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It's so hard to tell what is the truth and what is not on the forums.

Half of the people come in and say, it's impossible to recover data after it has been formatted so many times
and the other half says, that it's easy to do and you can never really delete all the information. LOL.
Who knows what the real truth is. I guess forums are generally good for opinions to be taken with a grain of salt
but not for undisputed hard cold facts.
How can anyone know who is really telling the truth?

Well I guess I never really had anything too important on my hard drive.
Just things like, addresses, phone numbers, passwords to forums, passwords to accounts,
ebay passwords, bank account passwords, paypal password, letters to girlfriend, emails to friends. etc. etc. etc.

Come to think of it, that info is kind of important.:confused:

Bah, the internet is worthless.

 
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Matthias99

Diamond Member
Oct 7, 2003
8,808
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Half of the people come in and say, it's impossible to recover data after it has been formatted so many times
and the other half says, that it's easy to do and you can never really delete all the information. LOL.
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I work in the storage industry, and here's my take on it: after you've low-level formatted / repeatedly overwritten the data with something else, there's no way to recover the data *through the original drive's read/write mechanisms*. The drive heads just aren't that sensitive; they're designed to detect '1' or '0' at a particular head and cylinder, not "well, this was probably a '1' that got overwritten by a '0' and then another '1' during the reformat". Unless you physically destroy or damage the platters, however, it is possible to take a drive apart and analyze the physical platters using specialized equipment to try and recover data from it. But nobody except law enforcement or a data recovery firm generally has access to this sort of equipment. Certainly, if someone has reason to believe there's very valuable information on that hard drive, they can go to some extraordinary (and very expensive) means to attempt to recover it. But rest assured that you are not really that important.

Just things like, addresses, phone numbers, passwords to forums, passwords to accounts,
ebay passwords, bank account passwords, paypal password, letters to girlfriend, emails to friends. etc. etc. etc.
Click to expand...

The better solution is to not store sensitive passwords, PIN numbers, account numbers, etc. on your computer in the first place, unless you have them encrypted (and in that case, don't store the encryption password on there either). I'd be more worried about spyware or getting hit with a trojan/backdoor if my system was full of data like that.

If you're concerned about security for email -- damn, it's easy for law enforcement to tap someone's email, again unless they're encrypting it. You honestly think someone would buy your hard drive on the off chance they could find your old emails, or your address book? Sorry, but unless you're a celebrity, I don't think this is a big issue.
 
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nx02nx02

Senior member
Dec 26, 2001
539
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0
I see. Well I never really stored my passwords on my hard drive by actually typing them in a text document and then saving it.

I mean like, I login to my bank account or paypal and I have to type in my password. So isn't that then stored in my
hard drive? Or is it not because it is a encrypted server?

If I go to paypal and login, it is an encrypted server so does that mean that my password that I type in will never be stored on my hard drive?

I guess if this is the case then I dont really have anything to worry about because I never stored passwords on my hard drive I just typed then in to login, etc. On the internet.
 
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CQuinn

Golden Member
May 31, 2000
1,656
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and the other half says, that it's easy to do and you can never really delete all the information.
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Nobody said that, even sharq admits that his project did not go to extraordinary lengths to remove
the data on the drives before attempting recovery.

For my 2 cents, there are several scenarios you need to consider for this issue, depending on your level
of concern/paranoia. These are all scenarios from the point of view of some person who might want to
access your re-sold drive to get sensitive information of some sort (Credit Card #s or account passwords).

Scenario 1: The drive is sold "as is" straight out of the machine with all data intact
(and yes, I have seen people sell drives/removeable media like this).
-- This is the best situation for a would be data thief, since all they have to do is scan the files for useable
information.

Scenario 2: All the files/folders on the drive have been deleted.
-- All they need is an undelete utility to get back to the state in scenario 1.

Scenario 3: The drive has been quick-formatted.
-- They need an unformat utility instead of an undelete utility.

(The above three are assuming the drive is FAT/FAT32 formatted.)

Scen4: The drive is fully formatted/ NTFS-formatted.
-- It can still be recovered with some unformat / data recovery utils, but will take much longer and probably
require another hard drive to copy recovered data to.

Scen5: The drive was encypted before being fully formatted.
-- The recovery may work, but without the decryption codes for the data it will not seem worth much effort

Scen6: The drive has been once-wiped (1s or 0s over-written on top of the format)
-- This would require more sophisticated recoevery software, and is no longer certain that the data you
recover is completely valid.

At this point, it is no longer really cost effective to try to recover the drive just in the hope of finding somebodies
credit info or some other secrets. Some hobbyist might, if they have no life or are trying to complete some
school project, but most other people would decide the drive is worth more to re-sell it or stick it in a machine
to use as is.








 
Jeff7181

Jeff7181

Lifer
Aug 21, 2002
18,368
11
81
Originally posted by: sharq
You can run all of the erasing tools, but it won't help you much. The kind of scrubbing actually required will basically render the hard drive useless. I did some work on computer forensics and their tools for a senior level class, and the only 100% way, is to break the platters in the harddrive, but then you can't sell it. :)
Yes the tools to recover the data are not cheap, and you can't buy them from your local Compusa or Bestbuy, but if someone wanted your data (I emphasize the word "IF") then it's not out of their reach.
Click to expand...

My spleen isn't out of reach if someone wanted either... but as you said, the key word here is if.

Unless you're a well known person and do very sensative work on your computer, a simple format is enough to protect your gigabytes of animal porn from being found.

Even if you were well known and have sensative data on your computer, I doubt you'd be upgrading your hard drive and selling the old one :)
 
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n0cmonkey

Elite Member
Jun 10, 2001
42,936
1
0
I think the real question people need to ask themselves, is how much is that information worth to someone else? Writing over it X number of times will keep most people from being able to see the data without spending a lot of money. Do you have data that will make them a profit after they spend all those dollars on data recovery proceedures? Probably not. Over write everything 3-7 times and you should be fine.

The differences between possible and feasible are big enough to make the validity of some of the claims here moot.

If you do have that kind of data, you should just destroy the drive. Period. ;)
 
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Acanthus

Lifer
Aug 28, 2001
19,915
2
76
ostif.org
No one wants your pr0n.

I just format then delete the partition. If you do that much work to get my Discover card numbers, you deserve my $5000 because you spent 10x that to get it.
 
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sharq

Senior member
Mar 11, 2003
507
0
0
Boy did I create a ruckus(sp?) :)
Like everyone, along with me, has pointed out, unless you have some reason to be paranoid, then just format it as ntfs, write over it once, and then delete the partitions.
If you are extremely paranoid, or feel that somoene is out to get you (once again, keyword is IF), then get a drill and go nuts.
 
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Matthias99

Diamond Member
Oct 7, 2003
8,808
0
0
Originally posted by: mx1mx1
I see. Well I never really stored my passwords on my hard drive by actually typing them in a text document and then saving it.

I mean like, I login to my bank account or paypal and I have to type in my password. So isn't that then stored in my
hard drive? Or is it not because it is a encrypted server?

If I go to paypal and login, it is an encrypted server so does that mean that my password that I type in will never be stored on my hard drive?

I guess if this is the case then I dont really have anything to worry about because I never stored passwords on my hard drive I just typed then in to login, etc. On the internet.
Click to expand...

Depends. I would *HOPE* that any reasonably secure site would not do something really stupid like storing your password in plaintext in a cookie on your hard drive. As long as they don't do something like that, you should be fine; when you use a secure site, the password is encrypted before even being sent out to the server, and should not ever be stored on disk (at least not in an unencrypted form).

You can get into trouble from things like cached online 'receipt' pages that show your full credit card number (most show it partially XXXed out, fortunately), or programs that store your username/password in the registry (a good reason not to use 'remember my username/password' for things like AIM), but, again, if you wipe the disk with a 'scrubbing' utility that overwrites the entire drive repeatedly with random data, they're not getting anything off of it without spending far more time and effort than it would really be worth.
 
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nx02nx02

Senior member
Dec 26, 2001
539
0
0
Originally posted by: piasabird
Try the software on this site:

http://www.killdisk.com/downloadfree.htm

It is suppose to be pretty good. Maybe someone has actually tried this.

You may not want to sell a hard drive with illegal material on it like Child pornography or illegal copies of operating systems.
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Nah I have never had anything illegal on my hard drives.
Just stuff that is important to me like, credit card numbers, passwords, etc.
Or atleast they have gone through an encrypted server like we were talking about
earlier in the thread.

bah I think I am being too cautious. I am probably making a big deal out of nothing.
This topic is interesting though, and educational.
I just dont want my credit card numbers and bank account numbers to fall
into the wrong hands. :)
 
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