DBAN time for 100gig HDD

How do I completely erase my PC?

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DBAN time for 100gig HDD

Postby bigdude » Mon Feb 07, 2005 6:47 pm

I know its a popular question but couldn't find definitive answer. I'm just looking for an approximate time it would take to wipe a 100gig HDD. I have a 2 year old Sony Vaio w/ 2.4 pentium and 1gig RAM. I have XP Home ed. I want to use the 35 times pass.
bigdude
 

Postby Gralfus » Mon Feb 07, 2005 8:50 pm

The 35 pass method takes a long time on any system. You really don't need to do it that way, as it is overkill.

The reason there is no definitive answer is that no one has sat down with all the different possible hardware configurations and timed DBAN on all the different hard drive sizes. And it is unlikely that anyone ever will.

Fire it up, let it run, and go do something for a few days and check on it periodically.
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Postby bigdude » Tue Feb 08, 2005 7:23 pm

So is 7 pass near nonrecoverable? On what level (i.e. gov't)?
bigdude
 

Postby Anonymous0 » Tue Feb 08, 2005 10:19 pm

1 pass PRNG will stop software recovery methods, but will not protect against a detailed analysis in a forensic lab.

7 pass PRNG will give you quite a good protection against hardware recovery, with a probability of 0.99 that every area of the disk will be reoriented once.

33 pass PRNG will very likely stop all hardware recovery attempts, with a probability of 0.99 that every area gets reoriented at least twice.

In all 3 cases, you have to make sure, that your HDD does not contain bad sectors. You can check for bad sectors with specific utilities that you can obtain from the disk manufacturer.
For Samsung this is the hutil.
I'd recommend you download the Ultimate Boot CD, UBCD.
Most drive specific utilities are on that CD, no matter whether you have a Maxtor or a Samsung, you'll likely find the one that applies to your harddrive.
Furthermore, you should only do 1 round PRNG at once. When the first round is finished (you selected 1 round in the menu), then restart your PC and repeat the process x times. Thus you can be sure, that the random noise is not stored in the internal cache and thus only the last pass is written to the drive, although DBAN already checks for this.

Now you might ask, how do I know this 7-pass and 33-pass stuff?

Well, in 2003 a member of one of the federal data protection agencies (yea, we got this cool stuff in Germany :D ) told a News magazine, that a deletion standard, that is advertised by our Federal Office for IT Security (www.bsi.de) isn't really secure. The BSI advertises a 3-pass standard without random numbers.
This guy, Roy Pfitzner, wrote an internal paper for his boss at the Agency.
However, this paper was then classified, because in his paper he explained how you could delete data so that even the intelligence services would not get anything, if properly applied.
Nevertheless, it seems that the Data protection agency somehow managed to make this information official.
In October 2004 they published a guide line on secure deletion of data from hard disks, you can find the german version here:
http://www.lfd.m-v.de/informat/magloe/magloe.html

I'm already working on a translation, but I'm still in exams, so you'll have to wait until end of March, unless someone else picks it up.
Maybe I'll ask my local Agency whether they can publish the original paper as well.

greets
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Postby Gralfus » Wed Feb 09, 2005 5:51 pm

Which all means that for most mortals, the 7 pass method is what to use. Unless you actually believe that the federal spooks really have an interest in your hard drive, and the vast majority of us will never even show up on their "radar". You would have to have something on your drive worth spending a LOT of time and money on before they would do anything beyond regular software recovery.
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Postby Guest » Thu Feb 10, 2005 12:17 am

I was asking this on another thread, but I dont know how to get more than 1 pass in PRNG. I can change the number of rounds no problem, but the default PRNG is 1 pass, and I dont see anywhere where I can change it.
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Postby fireontheway » Tue Dec 27, 2005 1:31 am

[quote="Gralfus"]Which all means that for most mortals, the [b]7 pass[/b] method is what to use. Unless you actually believe that the federal spooks really have an interest in your hard drive, and the vast majority of us will never even show up on their "radar". You would have to have something on your drive worth spending a LOT of time and money on before they would do anything beyond regular software recovery.[/quote]

When you said 7 pass, did you actually mean the pass or rounds.Sorry if i had to ask im terribly confused.At the moment my sisters pc is getting wiped with the following settings:

PRNG: Mersenne Twister
Method: PRNG Stream
Verfy: Last Pass
Rounds: 8

Is this level of wiping acceptable?
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Postby dajhorn » Tue Dec 27, 2005 2:36 am

Yes.

The defaults are safe. Don't change it unless you understand it.
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Postby fireontheway » Tue Dec 27, 2005 3:49 am

dajhorn, sorry for being a total newb but are you saying that PRNG with 8 rounds and 1 pass is overkill for my purpose? If so which method of wiping would you suggest because i have another hard drive to wipe. Thank's a bunch.
:)
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Postby dajhorn » Tue Dec 27, 2005 5:41 am

are you saying that PRNG with 8 rounds and 1 pass is overkill for my purpose?

This is adequate.

If so which method of wiping would you suggest because i have another hard drive to wipe.

I recommend using the default method of the latest DBAN release, which is currently one round of the DoD short method.
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