Re: Data protection

Eugene Leitl (
Tue, 18 Mar 1997 22:03:47 +0100 (MET)

On Tue, 18 Mar 1997, Robert Schrader wrote:

> Awhile back, someone - I forget who - made the comment that the only
> way to really erase data was with thermite. I'm not sure if the comment
> was indended literally, but...

Thermite (they still use it routinely to weld streetcar rails, a great
show even in the sunlight, fumes lit by lava, wow), or a sheet of
electrically ignited (system call Detonate() ) plastique taped onto the

> Basic thermite is just a combination of aluminum powder and iron oxide.
> ( hydroxide? I forget ) Sounds pretty similar to the composition of the

Oxide. Coarse aluminum powder. Fine aluminum powder withh lead oxide
kinda explodes.

> platter itself. Is it possible to make a platter of cast thermite?

I dunno whether it already happened, but the trend goes towards sputtered
high-tech stuff (on-glass? IBM?). The platter is still aluminum, though.
Thermite won't stand even weak centrifugal forces, though.

> If so, this opens up new horizons for really secure data.

Crypt, and destroy. Erase with grace.

> The microproccesor in the drive mechanism could be instructed to ask
> for a key at start-up. If it doesn't get it, it refuses to seek data.
> If it gets several consecutive bad keys, it ignites the disk.

I actually thought about several 100 g of plastique in the cabinet, for
software copy protection. (Better than dongles. Pirates having to wear
kevlar-lined pinstripe suits).

> It should be possible to rig a dead-man switch so that the case cannot be
> forced open without turning the platter into molten slag.

Of course ;)

> For the really paranoid, a cmos clock chip and battery could be added
> internally. If a period of several days goes by without the microprocessor
> getting the key, it ignites the disk. ( Of course the time period should
> be programmable so that one can take vacations )

Why risk missing the fun? Much better than a cranial explosive charge.

> Robert Schrader


P.S. aural float -- dub up the virus

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