Re: Writting on encrypted partion with Debian sarge reading with Knoppix

[Max Vozeler <max@nusquama.org>]

Hi Rainer,

On Sat, Aug 19, 2006 at 06:46:22PM +0200, Rainer Dorsch wrote:
> What I did:
> 
> On the Sarge side:
> 
> modprobe blowfish
> modprobe cryptoloop
> losetup -k 256 -e blowfish /dev/loop0 /udev/mdisk5
<...>

> When it comes to knoppix now, I tried
> 
> losetup -e blowfish256 /dev/loop0 /dev/sda5  # did not accept -k parameter
> mount -t ext3 /dev/loop0 /mnt/crypto
> 
> Then I got the error message:
> 
> EXT3-fs: unable to read superblock
> mount: wrong fs type, bad option, bad superblock on /dev/loop0,
<...>

This is probably because of the different default hash functions in
"normal" Debian losetup (package mount) and the loop-AES patched losetup
used in Knoppix. The Sarge losetup uses rmd160 to hash the passphrase,
whereas the loop-AES patched losetup on Knoppix probably uses sha512.
You can try to explicitly specify rmd160 with the -H option, like
"losetup -e blowfish256 -H rmd160 /dev/loop0 ..."

cheers,
Max