[Cryptography] Magnetic media destruction question

[Nico Williams]

On Mon, Jan 12, 2026 at 07:01:23AM -0800, Kent Borg wrote:
>        [...]. It is easy to make it much more expensive to reconstruct
> things (water down, maybe mix in other nasty stuff, squish out air, let it
> rot for a time) to impossible (pulp the the chaff into a slurry).

Pulping machines exist.  I would think the best way to destroy paper
documents is to shred them then pulp them with a pulping machine.  I
doubt anything can be recovered at that point.

For harddrives (including solid state ones) I'd say first always encrypt
everything (well, close to everything) on them, that way losing the keys
is the first step to destroying the data on the drives.  Then apply
whatever mechanical destruction machines you have, then apply some sort
of acid or solvent wash.  For bonus points heat / incinerate the
remains.  But the first step will get you quite far, well, as long as
you can reliably destroy the keys.  Of course, encrypting your storage
has other issues, like you'd better not lose the keys accidentally.

Nico
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