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Is 7 pass erase secure enough?


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11 replies to this topic

#1 bovril

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Posted 21 November 2014 - 09:38 AM

I am going to wipe out my external HD. I want every single piece of data irrecoverable. Obviously 35 pass is always better than 7 pass but is it really required? Wiping out 500gb with 35 pass would take about a week so it would be nice to make it quicker if it don't make any difference.



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#2 bludshot

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Posted 21 November 2014 - 10:37 PM

It depends what you mean by required? There are articles that say that 1 pass is enough and that more being needed is a myth. As far as I understand it, the methods for even possibly retrieving data after 7 passes are not available to whoever is likely to be trying to see your data, unless you are james bond or something.



#3 JohnC_21

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Posted 21 November 2014 - 10:51 PM

bludshot is right. A one pass wipe is enough, 35 passes is overkill. 3 times would work if you are really worried.

 

HTG Explains: Why You Only Have to Wipe a Disk Once to Erase It

 

http://www.it.cornell.edu/security/depth/practices/media_destruct.cfm


Edited by JohnC_21, 21 November 2014 - 10:52 PM.


#4 bovril

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Posted 22 November 2014 - 04:44 PM

Please I need more answers to this question. As many as possible please!



#5 sflatechguy

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Posted 22 November 2014 - 04:58 PM

Seven pass is what the military uses, and only on mechanical hard drives. Unless you've got ultra-sensitive data on that drive, 1-3 passes is enough. The 35-pass wipe is actually something of an urban legend: http://www.howtogeek.com/115573/htg-explains-why-you-only-have-to-wipe-a-disk-once-to-erase-it/

 

I should also point out that "wiping" SSD drives is totally unnecessary, as the drive is designed to actually delete the data completely when you issue the command. There are no leftover file fragments to wipe.



#6 NickAu

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Posted 22 November 2014 - 05:39 PM

Are you selling or giving away the HDD?

 

3 times would work if you are really worried.

 

Are you going to dispose of it by throwing it out?

Smash it with a hammer a few times.

 

Are you keeping it and just want to delete everything?

Just format it.



#7 bludshot

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Posted 22 November 2014 - 06:14 PM

Please I need more answers to this question. As many as possible please!

 

I recommend that people this concerned need to physically destroy the drive.



#8 bovril

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Posted 22 November 2014 - 06:56 PM

No I am not going to destroy it but keeping any data is not an option.



#9 Platypus

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Posted 23 November 2014 - 04:31 AM

What is the point of more answers? If they contradict, they're no help to you and if they're the same, then it's only people saying the same things over again.

 

In 2008 a challenge was issued to anyone who thought they could recover data from a single pass zero filled drive - even up to government agency (NSA, CIA) would have been accepted to see if they could recover even a file name, let alone contents. Nobody was prepared to attempt it.

 

http://www.hostjury.com/blog/view/195/the-great-zero-challenge-remains-unaccepted

 

Really, unless you have a legal obligation to certify to someone that a drive has been wiped to a specific requirement, all that matters is whatever will make you feel satisfied. Do that.


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#10 bovril

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Posted 24 November 2014 - 10:10 AM

What is the point of more answers? If they contradict, they're no help to you and if they're the same, then it's only people saying the same things over again.

 

In 2008 a challenge was issued to anyone who thought they could recover data from a single pass zero filled drive - even up to government agency (NSA, CIA) would have been accepted to see if they could recover even a file name, let alone contents. Nobody was prepared to attempt it.

 

http://www.hostjury.com/blog/view/195/the-great-zero-challenge-remains-unaccepted

 

Really, unless you have a legal obligation to certify to someone that a drive has been wiped to a specific requirement, all that matters is whatever will make you feel satisfied. Do that.

Well the thing is not all answers are the same.



#11 zingo156

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Posted 24 November 2014 - 11:15 AM

If you are worried, use the 7 layer wipe. I have tried recovering data from hard drives that were wiped by using a single pass with zeroing as a wiping measure. Even after 1 pass all of the data recovery software I had were incapable of recovering any data at all what so ever. That said, as mentioned: the military standard is 7 pass. If I had sensitive information I really wanted securely erased I would use 7 layer just to be safe. The old saying is always better safe than sorry. Even if it is overkill peace of mind is worth the extra time.


Edited by zingo156, 24 November 2014 - 11:19 AM.

If I am helping you with a problem and I have not responded within 48 hours please send me a PM.

#12 Platypus

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Posted 24 November 2014 - 05:42 PM

Well the thing is not all answers are the same.

Exactly. How does it help getting 12 different answers, in comparison to 5 different answers? And if 12 people said single pass is enough, would you happily accept that, or always have the niggly feeling you should have done 7?

 

Seriously, do what will make you feel comfortable about it.


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