Re: Default number of overwrites in shred

[Peter Eckersley]

On Fri, 2007-05-04 at 15:35 -0700, Paul Eggert wrote:

> I looked into the ATA side a bit more.  The hdparm command has
> --security-erase and --security-erase-enhanced options that look like
> they should use the ATA functions in question.  This could well be
> more suitable for the paranoid than 'shred' is.  However, for these
> features the current hdparm manual says "THIS FEATURE IS EXPERIMENTAL
> AND NOT WELL TESTED. USE AT YOUR OWN RISK."  So perhaps 'shred' should
> wait a bit before using this kind of facility, even if it's faster and
> more-secure.
> 
> In the meantime, perhaps the EFF would like to test hdparm?  (On their
> own drives, not mine!  :-)

Those hdparm commands zap the entire drive.  We could test them,
although it'd be hard to test them in any interesting way.  I saw some
mentions of an ATA secure blockwise erase too.  That should really be
linked to chattr +s in the filesystem code.  Maybe once we've got the
userspace parts of this problem sorted, we could look at that...

-- 
Peter Eckersley                            address@hidden
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Electronic Frontier Foundation    Fax  +1 415 436 9993