Encrypted home with Ecryptfs - How to store the key file if i missed it on first boot?

Question

I installed Ubuntu 12.04 with encrypted Home-directory. When I first booted I was given the option to store a key file to some Flash-drive (USB) or anything and there was a hint how to do it later. I wanted to do it later but now can't find where to find or how to generate the key file in any documentation.

So whats the command, where's the file? Ecryptfs-manger only offers me to generate a new pair.

Thanks a lot in advance

Answer 1

I happened to get the Message again now, after an update:

Record your encryption passphrase

To encrypt your home directory or "Private" folder, a strong passphrase has been automatically generated. Usually your directory is unlocked with your user password, but if you ever need to manually recover this directory, you will need this passphrase. Please print or write it down and store it in a safe location. If you click "Run this action now", enter your login password at the "Passphrase" prompt and you can display your randomly generated passphrase. Otherwise, you will need to run "ecryptfs-unwrap-passphrase" from the command line to retrieve and record your generated passphrase.

So ecryptfs-unwrap-passphrase is the answer.

Answer 2

I think the official docs here: https://help.ubuntu.com/12.04/serverguide/ecryptfs.html

Check Automatically Mounting Encrypted Partitions