Is this the proper way do permanently delete data?

[MarcoKaraki]

So, as far as I know, mechanical hardrives work by switching the little magnet binary switches to either a 1 or a 0.
By deleting data, you are simply telling the computer to stop recognizing that data.

So by that logic, to permanently delete that data, all you have to do is write over it by filling your hardrive with dummy txt files, correct?

 

[MongGrel]

I haven't done that to a disk in a long time but I used to just write 0's with the WD utility myself.

Depends, your HDD manufacturer might have something.

http://www.overclock.net/t/318829/good-program-to-write-zeros-to-hdd

 

[Essence_of_War]

So by that logic, to permanently delete that data, all you have to do is write over it by filling your hardrive with dummy txt files, correct?

That's in principle correct, but I would not rely on that to be effective without some sort of low-level tool that writes binary data directly to the disk.


Are you trying to figure out how to securely erase a hard drive before you sell it/recycle it/etc?

 

[videogames101]

No, physical destruction is the only way to be sure.

Even with a 0-write to a drive the old data can still be recovered in forensic labs.

If you can't destroy the drive, write random (not all 0s) data over the whole drive 10 times or so and you should be good.

 

[JeffMD]

For conventional means, using one of the many drive formatters that go over the platters with random data a couple times is good enough. You will generally not recover data through the drive itself. Forensic wise, transferring the platters to an enclosure where heads can pickup the edges of sectors where old data can remain. Much like a paintball, the drive head aims for the center and changes as much of the sector it can, but it won't hit %100 of that sector. repeated formats help prevent recovery but the only sure way is a bullet.

 

[Mr Evil]

Overwriting the whole drive may leave small amounts of data behind if any sectors have been reallocated. To ensure that those sectors are wiped too, you should use the ATA Secure Erase command. This works on SSDs too.

...Even with a 0-write to a drive the old data can still be recovered in forensic labs...

There is no evidence that this is possible with any modern drive after even a single overwrite. It is was possible, then it would indicate that hard drive manufacturers are not storing data as densely as they could, which would never happen.

 

[MarcoKaraki]

HAHA! It's not like I'm doing criminal things you guys! :awe:

I'm selling my laptop and just in case the guy wants my private info, I want to delete it permanently. It's not like a forensic lab is going to investigate me

 

[MarcoKaraki]

I haven't done that to a disk in a long time but I used to just write 0's with the WD utility myself.

Depends, your HDD manufacturer might have something.

http://www.overclock.net/t/318829/good-program-to-write-zeros-to-hdd

Hey that looks promising if I had a virus that was very stubborn throughout OS re-installs.

 

[Essence_of_War]

If you're selling the laptop and part of the deal is that it includes the OEM windows, you should:

1) Prepare a recovery medium
2) Secure erase the hard drive (here's a good overview of how ot do that with HDPARM)
3) Re-install the OS from the recovery medium and hand it off to the new owner w/ any relevant activation codes so that they can prepare their own recovery medium.

 

[MarcoKaraki]

If you're selling the laptop and part of the deal is that it includes the OEM windows, you should:

1) Prepare a recovery medium
2) Secure erase the hard drive (here's a good overview of how ot do that with HDPARM)
3) Re-install the OS from the recovery medium and hand it off to the new owner w/ any relevant activation codes so that they can prepare their own recovery medium.

That's just what I needed to know. Thank you

 

[mindless1]

You don't need to do all that stuff, to spend so much time on it when selling something at a greatly reduced, used price.

Just install a secure delete type utility before deleting your personal files, email, and browser cache/history/etc. Here's one:
http://eraser.heidi.ie/

Besides, it's usually better to have the system already configured beyond an initial windows installation at time of sale so you can demo that everything works.

 

[videogames101]

Overwriting the whole drive may leave small amounts of data behind if any sectors have been reallocated. To ensure that those sectors are wiped too, you should use the ATA Secure Erase command. This works on SSDs too.


There is no evidence that this is possible with any modern drive after even a single overwrite. It is was possible, then it would indicate that hard drive manufacturers are not storing data as densely as they could, which would never happen.

I just read some data saying there is a single digit percentage chance of recovering a 32-bit integer. Non-zero. The cost of doing multiple randomized passes is so low, I wouldn't risk it.

 

[John Connor]

DBAN for platters, Parted Magic for SSDs.

 

[MarcoKaraki]

You don't need to do all that stuff, to spend so much time on it when selling something at a greatly reduced, used price.

Just install a secure delete type utility before deleting your personal files, email, and browser cache/history/etc. Here's one:
http://eraser.heidi.ie/

Besides, it's usually better to have the system already configured beyond an initial windows installation at time of sale so you can demo that everything works.

Oh, that works too i guess. thx

 

[Mr Evil]

I just read some data saying there is a single digit percentage chance of recovering a 32-bit integer. Non-zero. The cost of doing multiple randomized passes is so low, I wouldn't risk it.

Could you provide a link please? I have never found any tales of it happening before, or any data recovery companies that even claim to be able to do it. It would effectively entail being able to read >1 bit of information from a single magnetic domain.

 

[Charlie98]

No, physical destruction is the only way to be sure.

Even with a 0-write to a drive the old data can still be recovered in forensic labs.

If you can't destroy the drive, write random (not all 0s) data over the whole drive 10 times or so and you should be good.

I have a good friend of mine that is in the forensic data recovery business.. here is his reply:

In the old days, he would have been close. Not even the NSA does 10 passes. They used the DoD 7 pass process which did something different each time. This is not the case in the last 10 years. I can write one pass and it's not recoverable.

 

[MrTeal]

I would say that if the data you have on the hard drive is so valuable that there's any question someone might take it to a forensics lab, just spend the $30 to replace the HDD in your laptop and put a 1/2" drill bit through your existing one.

 

[John Connor]

I would say that if the data you have on the hard drive is so valuable that there's any question someone might take it to a forensics lab, just spend the $30 to replace the HDD in your laptop and put a 1/2" drill bit through your existing one.

The FBI can still recover...

 

[mindless1]

^ Evidence or it didn't happen.

 

[MrTeal]

^ Evidence or it didn't happen.

It'd like to see a case study on this, too. The last time I did this was an old laptop that I didn't feel like powering up to wipe before tossing in the trash, but the drill shattered the platter and you could hear the pieces tumbling around in it. While no doubt there was still some data encoded on the platter, saying even the best funded lab could recover anything from it sounds like Avengers-style "We're sweeping every wirelessly accessible camera on the planet".

 

[silicon]

The FBI can still recover...

i think the government run the write rewrite 7 times to ensure a permanent delete. I would do this personally if selling a laptop or desktop but what is the chance a normal user would want to recover data? Almost none in my opinion. The big problem is when drives are returned on rma for replacement. what do these companies do with those drives? They are sold by the pound to people who try to repair them and often they get data from them.

 

[Charlie98]

i think the government run the write rewrite 7 times to ensure a permanent delete. I would do this personally if selling a laptop or desktop but what is the chance a normal user would want to recover data? Almost none in my opinion. The big problem is when drives are returned on rma for replacement. what do these companies do with those drives? They are sold by the pound to people who try to repair them and often they get data from them.

I don't think that's true, given the amount of 'refurb' drives given back from an RMA, or refurb drives available for retail sale.

I've had 2 drives RMA'd... an SSD and an HDD. Both were compensated by sending me a refurb drive.

 

[John Connor]

^ Evidence or it didn't happen.

Example A: http://www.popularmechanics.com/tec...66/how-to-read-a-smashed-hard-drive-14877558/

 

[silicon]

I don't think that's true, given the amount of 'refurb' drives given back from an RMA, or refurb drives available for retail sale.

I've had 2 drives RMA'd... an SSD and an HDD. Both were compensated by sending me a refurb drive.

i should have said big box stores and not the manufacturer.

 

[MrTeal]

Example A: http://www.popularmechanics.com/tec...66/how-to-read-a-smashed-hard-drive-14877558/

A popular mechanics article claiming that it's theoretically possible to glue the platter back together? That's not exactly an solid example of it ever having happened or actually being possible. The comments on that weren't very kind.

Counterpoints: http://www.bankinfosecurity.com/forensics-when-data-truly-lost-a-5380/op-1
http://www.cbldatarecovery.com/blog/data-recovery/cbl-pictures-shattered
https://blog.gillware.com/data-recovery/data-recovery-hard-drive-platters
http://www.vitaldata.ca/unrecoverable.html