[dm-crypt] Size of LUKS header and how to overwrite

Sven Eschenberg sven at whgl.uni-frankfurt.de
Wed Feb 10 21:29:07 CET 2016

Ah, I see. Well the FAQ gives alternatives and more information on the 
size of the header for different keylengths and so on. But as the 
header+keymaterial can hardly be bigger than the offset of the encrypted 
payload on the backing device a dd with count=payload-offset and bs=512 
indeed does the trick.

Of course you'd have to check the payload offset of that particular 
container and not mix any numbers etc. .



Am 10.02.2016 um 21:13 schrieb Michael Kjörling:
> On 10 Feb 2016 21:07 +0100, from sven at whgl.uni-frankfurt.de (Sven Eschenberg):
>> Yes, it will overwrite the header and potential free space after the
>> header up to the first sector of encrypted data.
>> Does this seem so weird?
> No, but given the somewhat roundabout way this was described in the
> FAQ at least last I looked, this seems like a much easier way to
> describe it...

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