I'm using arch linux with an encrypted luks root partition (boot unencrypted), with a passphrase yet. Now I have a keyfile (3072 bytes), that's written to USB-Stick this way:
sudo dd if=tempKeyFile.bin of=/dev/sdd bs=512 seek=1 count=6
and also set as additional pass
sudo cryptsetup luksAddKey /dev/sdb6 tempKeyFile.bin
When I open the partition manually with:
sudo cryptsetup --key-file tempKeyFile.bin open /dev/sdb6 luks_root
everything works, the partition is mapped and can be mounted.
Now my kernel-parameter-line in
grub.cfg looks like this:
linux /vmlinuz-linux root=UUID=$UUID_OF_luks_root$ rw cryptdevice=UUID=$UUID_OF_sdb6$:luks_root cryptkey=/dev/sdd:1:6
But when booting, I get this error:
No key available with this passphrase.
Invalid Keyfile. Reverting to passphrase.
I already tried offset 2 instead of 1, but same result. I noticed it doesn't say, that the keyfile could not be found/read, but was incorrect.
There seems to be little documentation about this way of storing luks keyfile. Arch-wiki mentions it, but very briefly and I seem to be conform, so I think it should be possible.
mkinitcpio.conf MODULES, BINARIES and FILES are empty and I set:
HOOKS=(base udev autodetect keyboard modconf block encrypt filesystems fsck)
so block is right before encrypt.
What's the problem here?