[dm-crypt] No key available for this passphrase

Marcos marcos at tenak.net
Sun Sep 9 14:53:08 CEST 2012


Hi,

On 08.09.2012 23:47, Arno Wagner wrote:
> Wups, what is that? Quite non-standard. Did you select that yourself?

As per the docs I read back in the time, yes, I selected that cipher.

>> Hash spec:     	sha1
>> Payload offset:	3016
>> MK bits:       	384
>
>
> With that your first keyslot should be from 0x1000 to 0x2ee00.

Find the 'hd' dump at [1], from 0x1000 to 0x2ee00 (didn't attached
because its size is 329K).

>> Key Slot 0: ENABLED
>> 	Iterations:         	254001
>
> Pretty large. Unless you have a liquid-nitrogen cooled
> CPU, did you increase the iteration time?

Nope, actually, the problem is on a laptop hard disk...

> Have you looked at the whole keyslot up to 0x2ee00?

I haven't untill you pointed me to do it with this email :)
It's attached.

And having it done after running the code you attach in another
email, going straight to the low-entropy blocks that it points
to, I have found what seems an image file:

0002a000  ff d8 ff e0 00 10 4a 46  49 46 00 01 01 01 00 90  
|......JFIF......|
0002a010  00 90 00 00 ff e1 00 16  45 78 69 66 00 00 4d 4d  
|........Exif..MM|
0002a020  00 2a 00 00 00 08 00 00  00 00 00 00 ff fe 00 17  
|.*..............|
0002a030  43 72 65 61 74 65 64 20  77 69 74 68 20 54 68 65  |Created 
with The|
0002a040  20 47 49 4d 50 ff db 00  43 00 05 03 04 04 04 03  | 
GIMP...C.......|

One thing I don't understand: as per the docs I read for setting
the encryption, I selected a size of 384 bits for the key (that
in the case of lrw just 256 are used). What are we looking for
at 0x2ee00 far?

> Most people are hosed in your situations, but there have been
> some miraculous recoveries. So really knowing what happened
> is the key.

I suppose it. With an analysis of what happened it's all easier.

Thanks,

[1] http://dl.tenak.net/563cc336/hd_devsdb2_0x1000-0x2ee00.dump.bz2
-- 
Marcos
http://tenak.net/


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