I had a Host with Ubuntu 12.10 installed, and the entire harddrive was encrypted (with LUKS it appears), I remember the passphrase, but I have trouble to "open it".
I am now on a beta version of Ubuntu 14.04, installed on a new harddrive. the old hard-drive is also still connected. the new drive is sda and the old drive is sdb
when I try to open the drive in "files" it ask for the passphrase, and when entered says that it does not find a filesystem.
I googled it and found this:
sudo cryptsetup luksOpen /dev/sdb5 myopen
and
sudo mount /mnt/open
with a fstab like this
/dev/mapper/myopen /mnt/open ext4 defaults,noauto 0 1
but I get this error:
mount: wrong fs type, bad option, bad superblock on /dev/mapper/myopen,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so