Secure formatting takes centuries

[Sciuriware]

Hello,
I am formatting some old 2Tb USB drives by Disk Utility on max. security.
Well, it takes more than 24h a piece ....
Any idea if this is better than formatting to the minimum and then filling up with trash-text (meaningless data)?
;JOOP!

 

[russell_314]

Hello,
I am formatting some old 2Tb USB drives by Disk Utility on max. security.
Well, it takes more than 24h a piece ....
Any idea if this is better than formatting to the minimum and then filling up with trash-text (meaningless data)?
;JOOP!

Does it offer a one or two pass option? That’s usually sufficient unless you really have something you’re concerned about on the drives. In that case perhaps consider physical destruction after wiping them. I wouldn’t try manually filling the hard drives with data because that could be unreliable.

 

[Sciuriware]

Does it offer a one or two pass option? That’s usually sufficient unless you really have something you’re concerned about on the drives. In that case perhaps consider physical destruction after wiping them. I wouldn’t try manually filling the hard drives with data because that could be unreliable.

Well, the real problem is uncertainty: you could never guess what tomorrow brings w.r.t. detecting methods.
I've seen scientific methods to make the bits at the edge of tracks on wiped rotating disks visible.

All my friends have the attitude: "I've nothing to hide, it won't happen to me" w.r.t. data, media and internet.
I do not think like that.
B.t.w: a 30 hour erase, only once, is no problem for me, it may run at night.
Thanks for reading the question.
;JOOP!

 

[chabig]

Hello,
I am formatting some old 2Tb USB drives by Disk Utility on max. security.
Well, it takes more than 24h a piece ....
Any idea if this is better than formatting to the minimum and then filling up with trash-text (meaningless data)?
;JOOP!

Is this drive for your personal use? If so, there is no need to secure erase before you use it. Secure erase is used before you dispose of a disk. And yes, it's very time consuming, so just let it run even if it takes days.

 

[Sciuriware]

Is this drive for your personal use? If so, there is no need to secure erase before you use it. Secure erase is used before you dispose of a disk. And yes, it's very time consuming, so just let it run even if it takes days.

Right: it's for disposal. And it just completed after 28 hours.
;JOOP!

 

[KALLT]

I've seen scientific methods to make the bits at the edge of tracks on wiped rotating disks visible.

Where have you seen those? This might be based on old research.

There is a well-known paper written by Peter Gutmann in 1996 that is ostensibly responsible for the belief that you need a multi-pass overwrite to ‘wipe’ data from hard disks. Even it 1996 it was already virtually impossible to reliably recover chunks of data that were overwritten once (s. https://security.web.cern.ch/rules/images/The Great Wiping Controversy.pdf).

For a 1 TB drive it should be more than enough to “zero out” data (i.e. overwrite with zeros) to avoid recovery.

As usual: if you store sensitive data on a storage medium, then you want to think about encryption, not about secure erase afterwards.

Any idea if this is better than formatting to the minimum and then filling up with trash-text (meaningless data)?

No. Any type of secure erase that uses overwriting (zero out, random data, multi-pass, etc.) is already writing meaningless data.

 

[Sciuriware]

Where have you seen those? This might be based on old research.

There is a well-known paper written by Peter Gutmann in 1996 that is ostensibly responsible for the belief that you need a multi-pass overwrite to ‘wipe’ data from hard disks. Even it 1996 it was already virtually impossible to reliably recover chunks of data that were overwritten once (s. https://security.web.cern.ch/rules/images/The Great Wiping Controversy.pdf).

For a 1 TB drive it should be more than enough to “zero out” data (i.e. overwrite with zeros) to avoid recovery.

As usual: if you store sensitive data on a storage medium, then you want to think about encryption, not about secure erase afterwards.


No. Any type of secure erase that uses overwriting (zero out, random data, multi-pass, etc.) is already writing meaningless data.

It was about those days that I attended a congress where they showed pictures of "bit remains".
Anyway ..... time to turn to SSD 'disks': 2ce as fast and without 'remains'.
;JOOP!

 

[KALLT]

It was about those days that I attended a congress where they showed pictures of "bit remains".
Anyway ..... time to turn to SSD 'disks': 2ce as fast and without 'remains'.

Consider the scale though: 2 TB equals 16 trillion bits. A bit is infinitesimal in comparison. Also consider that data is usually stored in bytes (8 bits), so being able to recover individual bits makes it even less likely to recover usable data.

SSDs have a different problem though: you cannot reliably wipe SSDs by overwriting, since this is not how SSDs work. You have to rely instead on the microcontroller to trim unused/deleted blocks.

 

[Sciuriware]

Consider the scale though: 2 TB equals 16 trillion bits. A bit is infinitesimal in comparison. Also consider that data is usually stored in bytes (8 bits), so being able to recover individual bits makes it even less likely to recover usable data.

SSDs have a different problem though: you cannot reliably wipe SSDs by overwriting, since this is not how SSDs work. You have to rely instead on the microcontroller to trim unused/deleted blocks.

Trim? is that function performed by Disk Utility Erase?
;JOOP!

 

[KALLT]

Trim? is that function performed by Disk Utility Erase?

For the internal Apple-branded SSD, likely yes. Trim is also executed periodically. However, external SSDs might not use trim, either because Apple does not support the disk or the microcontroller/interface cannot process the trim command. You should not rely on it to wipe data, instead use encryption, preferably before you even write any personal data onto it.