Destroying a hard drive

[Bill Ricker]

>     What is the most efficient way to destroy the data on a hard drive
> before junking it?  Normal file erasure leaves the data intact.  Secure
> erasure or reformatting takes too much time, and the drive may not be
> working well enough to complete the operation.

Good practice would swap the disk out before it's too sick to reliably
run core-utils shred(1).
Once it IS too sick to run shred(1), the cost of exploitation of the
disk by the opponent has gone up quite a bit ($1500 datarecovery
service or equivalent organic resources).
If the enemy is the fleamarket customer buying a pile of parts looking
for credit card or pr0n account #, good enough to make the move on to
the next one.

If the enemy is a major corp or government out for YOUR secrets, not
adequate ... and yeah, a hammer blow would leave too many bits
readable by those with various scanning force microscopes and magnetic
dies ...


>     Has anybody suggested a chemical solvent wash?  (Wash fluid disposal
> might possibly be a problem.)

Back when disk platters were stored in cake boxes and loaded into
washing machines, one local firm left the machine room windows open at
night to save on air-conditioning. Certain disks were swapped for day
vs night batch runs. One multi-platter disk unit was left by window
without a cake cover over it one night. It snowed. The operator didn't
notice snow between the platters when he scooped it up with a
cake-cover and slotted it into the washing machine. Boy did it wash
the platters.  The melting snow was enough -- back then -- to free the
iron-oxide from the platters. Splat, all the bits sprayed onto the
inside of the washingmachine drive unit. In random alignment.

So yes, a solvent should do it if you pick(led) the right one. But
they're hazmat.
And may react nastily with something else in the drive.

>     Do the rather exotic magnetic coatings have a low enough Curie
> temperature to destroy the magnetization in an oven?  Our kitchen oven
> goes to 270C (520F) or so, but magnetite requires 560C.  Cobalt
> compounds are higher.  Using a Bernz-O-Matic torch would simplify
> disassembly - just remove the cover.

If I wanted a secure proxy cache to self-destruct on tamper, I'd
request drives with magnesium platters and case ...

Unsubstantiated rumor was certain crypto gear came with thermite bomb
just above in case of capture. If you embed the drive in molten iron
...

>     Not that I have anything to hide, you understand.  Just curious.

Take it to the gun club and let 'em use it for target practice.

-- 
Bill
n1vux at arrl.net bill.n1vux at gmail.com