Cryptsetup luks "Invalid password" F16

[Heinz Diehl]

On 18.02.2012, Frank Murphy wrote: 

> Switched on this morning.
> Can get into /devsda4 (root)
> 
> But as systemd starts doing it's stuff,
> dropped to  emergency shell.
> 
> Both /dev/sda3 (swap), /dev/sdb2 (home)
> "invalid password"

I have encountered this several times on my job machine (F16),
but could not find the root cause of this annoying behaviour yet.
The same machine worked fine with F14 and F15.
 
> Now have tried: (twice, same result)
> dd =if=/dev/urandom of=/root/newkey
> cryptsetup luksAddKey /dev/sdb2 /root/newkey
> Enter any Password: made one up
                      ...........

> "No key with this paraphrase"
> Stumped.

Here's the problem: you have to provide a valid keyfile or passphrase to authentificate,
but you must NOT give a new password/passphrase here. See "man cryptsetup" and the 
explanations which come with "luksAddKey".