data shredder

[Gilles Gravier]

Hi!

On 22/12/2009 05:26, NoOp wrote:
> On 12/21/2009 01:51 PM, Amedee Van Gasse (ub) wrote:
>   
>> Even a 0.907185 kg, as someone wrote, won't be enough against *really*
>> fancy hardware.
>>     
> Just how fancy do you wish it to be? A 2 lb hammer (0.907185 kg) works
> just fine on old drives. You just need to use 7x pound to get the
> necessary result. Worked for me in my past life; 8 years as a ciphony
> specialist for some world government (C4 works better but can't do that
> now).
>
> But all of this is getting a bit silly isn't it? The OP asked for a
> "date shredder". He didn't specify how 'shredded' the data needs to be.
> Several 'reasonable' options have been provided & the thread now has
> drifted into disertations & theory on data shredding.
>  I suppose that's expected, but any search of the list archives will
> turn up previous.
>
> Other than 'shred won't do this', 'TrueCrypt can do this', I've not seen
> any of the "expert" contributor that have recommend much.
>
> o I recommended looking at shred and scrub.
> o Gilles recommended TrueCrypt (which isn't really an answer to the OP's
> question, and has nothing to do with the OP's question)
>   
I beg to differ. It has all to do. If the OPs aim is to prevent people
from recovering his/her data on discarded or stolen disks, then
initially storing that data in an encrypted containers achieves that aim
with the security level provided by the strength of the encryption
algorithm chosen. Unless the key is also made available to the attacker,
the data is just as well protected in an encrypted container as if it
were shredded in some other way. It's just random junk. You can go to
the extreme of changing the key to a random value before discarding the
disks if you want.

Now if you are trying to prevent people from accessing data on a running
system with a mounted disk... well... once the encrypted disk is
mounted, for all purposes, it's just another FAT disk... so all FAT
tools apply for recovering data, and shredding is in order. At this
point, since the system is running, and not being disassembled to look
at phantom magnetic data, simple shredding is enough (since when you
disassemble it, you lose the access to unencrypted data).

So again, before saying it's got nothing to do, maybe we try to refine
the OP's scenario and then pinpoint the right answer...

Gilles