[Snake]

Quote:

Originally Posted by ServinginEcuador The Boot n Nuke is the way to go. It is widely reported about how a simple fdisk and format won't rid your drive of personal info. There was a whole 20/20 investigation or something on this, and they talked about people having their personal info stolen when they donated a computer they thought was wiped clean. Even installing Windows onto the newly formatted drive won't erase everything.

It's overhype. FDISK / FORMAT does indeed overwrite with zeros - what they, those "investigative reports", do is take the drive to a tech who uses a scope to retrieve the data. What they 'read' back is magnetic latency of a sector's bit when overwritten just once or twice - the heads can still detect the faint latent magnetic residue of the original data...with the right equipment, that is.

The real problem is that FORMAT defaults, since Win98, to a quick format that only wipes the FAT and therefore leaves the data area intact.

What you need to do is FORMAT C: /u (unconditional switch) that forces Windows to overwrite all sectors with zeros and tells Windows NOT to make a unformat entry for the FAT table (yes, that is part of the default). The /U switch is now undocumented but was standard on Win98.

 

[Alexhifi]

dd if=/dev/zero of=/dev/hdb
dd if=/dev/random of=/dev/hdb
dd if=/dev/zero of=/dev/hdb

Done.

-Alex

 

[Zanth]

Alex just listed my quick and dirty method. Though that DBAN is wicked cool,

dd if=/dev/zero of=/dev/hdb
dd if=/dev/random of=/dev/hdb
dd if=/dev/zero of=/dev/hdb

Just works sooooo well

 

[Stephonovich]

Snake, I wasn't aware that Windows' format actually wrote 0s to the entire drive. Interesting. That explains the reason for a Quick option, though...

As for the security hype, you're partially right. Depending on what method you used to erase it, there are programs that can recover data by comparing contextual information, among other methods. This obviously has problems if the drive is heavily fragmented, however. And as for the scope, that will recover pretty much anything. One thing I always found odd; if the DoD claims that their method (0/1 pass over entire disk 6 times, government code wipe, then a verification - unless I'm mistaken) is so secure, why do they grind their disks up when discarded, and then incinerate he fragments?

For most people, however, 1 pass of random data should suffice to keep your information safe.

 

[The_Mac]

Quote:

Originally Posted by Stephonovich Snake, I wasn't aware that Windows' format actually wrote 0s to the entire drive. Interesting. That explains the reason for a Quick option, though... As for the security hype, you're partially right. Depending on what method you used to erase it, there are programs that can recover data by comparing contextual information, among other methods. This obviously has problems if the drive is heavily fragmented, however. And as for the scope, that will recover pretty much anything. One thing I always found odd; if the DoD claims that their method (0/1 pass over entire disk 6 times, government code wipe, then a verification - unless I'm mistaken) is so secure, why do they grind their disks up when discarded, and then incinerate he fragments? For most people, however, 1 pass of random data should suffice to keep your information safe.

Why would a man ever want to wear suspenders and a belt? It's not that you don't trust your method, it's that you trust something else as well, and when you're dealing with some material, you can never be too secure.

If I ever needed to really destroy a disk, I'd DBAN it and then drill through all the platters with a nice drill, but that's only if I really needed to.