gbde blackening feature - how can on disk keys be "destroyed"
olli at lurza.secnetix.de
Fri Jul 15 11:58:13 GMT 2005
David Kreil <kreil at ebi.ac.uk> wrote:
> So, even if one doesn't know how to disable device caching, if a typical disk
> cash is 8MB, I suppose one could flush it through by writing 20MB. so, if one
> has |key|20MB bla| on disk and one wrote |random|20MB bla| that should ge the
> "random" bits overwriting the key on disk (but for hardware level sector
> remapping but that is a rare event). One would have to bypass the operating
> system cache though but I guess you would know how to do that, right?
> This should take less than 1s on a modern disk, i.e., less than half a minute
> for the entire procedure, x4 = 1-2 minutes, which should be fast enough for a
> final destruction.
That sounds like you want to overwrite the same location
on the disk more than a hundred times. That's not even
paranoid, it's completely pointless.
I suggest you read this document, ESPECIALLY the section
"Epilogue" near the end:
It suggests that -- with any modern hard disk drive -- a
few passes (say three) of overwriting with random data are
Oliver Fromme, secnetix GmbH & Co KG, Marktplatz 29, 85567 Grafing
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