[dm-crypt] Using dmsetup directly instead of cryptsetup

Milan Broz mbroz at redhat.com
Sat May 21 21:33:00 CEST 2011

On 05/21/2011 08:40 PM, dhvvcb at lavabit.com wrote:
> Usually I run command
> cryptsetup -d /path/to/key -c aes-cbc-essiv:sha256 -s 256 create
> hdd2 /dev/sdc
> and /dev/mapper/hdd2 is created.
> I tried to follow the example given on home page
> http://www.saout.de/misc/dm-crypt/

That page is pretty obsolete today, http://code.google.com/p/cryptsetup/
is home page now.

Why do you want to use dmsetup?


cryptsetup -d /key -c aes-cbc-essiv:sha256 -s 256 create x /dev/sdb

is equivalent to

echo 0 $(blockdev --getsz /dev/sdb) crypt aes-cbc-essiv:sha256 $(xxd -p -c 32 </key) 0 /dev/sdb 0 | dmsetup create x

(xxd is helper program in vim package)

I guess the hex representation is just wrong in your case,
hexdump produces different order of bytes.

Use cryptsetup a check with "dmsetup table --showkeys".


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