How do you destroy a hard drive?

The question of hard drive destruction is often raised, when people want to prevent access to their data, e.g. getting rid of old computers.

Questions include:

• How do I destroy my hard drive? Will drilling it work?
• Can I burn my hard drive, will that work ?
• Can I put it in water?
• How many times do I need to wipe a hard drive, to get rid of all data?

Often, the answers involve “the only thing that destroys a hard drive is thermite” or “wipe the drive 100 times, then grind it up into a fine dust and then melt the dust”.

These statements almost certainly come from those who have never been in a data recovery clean room, and certainly never worked in one.

Destroying data, on a hard drive, is relatively easy and can be done one of two ways:

1)      Wiping the entire hard drive. Just once. Not 3 or 32 or 320 times

2)      Destroying the platters. Once the platters are destroyed recovery is impossible.

The latter option can be achieved by a variety of ways, such as drilling the hard drive. In theory “somebody” could read the data around the holes, though no commercial company would ever do that. As the governments outsource their major data recovery work, to commerical companies, from the NASA Columbia disaster to international terrorist incidents if its very technical and very important it gets outsourced. Therefore who exactly “somebody” is, is unclear.

The idea that overwritten data, on a modern hard drive, can be recovered is just fanciful. Nobody has ever recovered data an overwritten modern drive, and nobody has said they can, it’s merely a theory, an old theory that was never tested or proved. However, when this theory was tested, it was not possible.

Remember wiping data is not formatting or deleting data. It is wiping every single sector on a hard dive.

In short there no evidence for recovering wiped data but there is evidence to showing wiped cannot be recovered.

Physical Methods that will not work to destroy data on a hard drive include:

• Throwing it in the water (this does not do much)
• Setting it on fire (the temperature is not going to be high enough at home)
• Throwing it out of the window. Hard drives can take quite a bit of G force.  They are not heavy so the impact of the hard drive on the ground is not likely to destroy the platters.
• Drive over the hard drive. A car, or even a tank, driving over a hard drive will do nothing, any more than they  would driving over a book. Unless the drive is actually flattened, the platters are not going to be destroyed.

Electronic Methods that will not work in destroying data are:

• Deleting files
• Formatting files
• Shredding files/Wiping Files

The whole drive needs to be wiped, not just some of it. Nothing else can guarantee all data is gone.