Thread (15 messages) 15 messages, 4 authors, 2007-08-31

Re: Problem using dm-crypt with geode LX800 AES-Engine

From: Markus Huehnerbein <hidden>
Date: 2007-08-29 20:29:13

Sebastian Siewior wrote:
* Markus Huehnerbein | 2007-08-29 16:41:57 [+0200]:
quoted
Thanks a lot! I confirm that it works with "-s 128" and also if "-s" is
skipped! But if I try to use cryptsetup with ESSIV (cryptsetup -c
aes-cbc-essiv:sha256 -y -s 128 luksFormat /dev/hda2) I get the same
what about sha128 instead?
quoted
error. If the "geode-aes" does not support essiv why is this task not
performed by another algorithm in the cryptoAPI?
Actually it is. geode does not support keys != 128 bit. ESSIV uses as
key the output of sha256 what is 256. Check dmesg please. If my theory
is correct than you should see in dmesg or somewhere:
"Failed to set key for ESSIV cipher"
Is it?
Yes, again you're right, if I use a hash with 256 bit I get the
following syslog errors:

device-mapper: table: 254:1: crypt: Error initializing ESSIV hash
device-mapper: ioctl: error adding target to table
device-mapper: ioctl: device doesn't appear to be in the dev hash table.

Unfortunately there is no support for sha128 in the Kernel so I tried
md5 as md5 also generates a 128 bit value.

Preparing the Volume with:
	cryptsetup -c aes-cbc-essiv:md5 -y -s 128 luksFormat /dev/hda2
works fine ("Command successful" and no errors in the syslog) but when I
try to open the device
	cryptsetup luksOpen /dev/hda2 devdmcryptluks
I get "Command failed." after entering the (correct) password. I also
tried "luksOpen" with the same arguments as "luksFormat" but the same -
"Command failed." without any trace in the syslog...
quoted
Thanks,
Markus
Sebastian
Thanks again,
Markus
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