Ubuntu – Recovering from a move of /home when it’s encrypted (ecryptfs)

First of all, if I remember correctly you have to check a box to install Ubuntu with an encrypted home directory, but I could be wrong. It certainly looks like it's encrypted.

Secondly, the bad news: if you encrypted the home directory at boot, it doesn't use your account password, but a separate pass phrase. After you first booted a pop up comes up with the question if you want to backup your encryption pass phrase for the home directory, recommending you get save it somewhere safe. There is a way to get the password at a later stage, but only if you can access it, so before anything goes wrong with your system. If you don't have the pass phrase, the only possible way to get it back is by brute forcing it, which, at the moment, is practically impossible.

Now that I think of it, after writing the previous text, if you made regular backups, you should be able get the key back. Did you make backups?

Edit:

Just test this answer and it works to get the pass phrase on a still working system, but you should save it somewhere safe, of course. :D

Edit2:

So I just looked further into it and if:

• you have a backup of your old home files AND;

• it included the ~/.ecryptfs folder with the wrapped-passphrase file

you can unlock it with the command:

ecryptfs-unwrap-passphrase /path/to/wrapped-passphrase

It will ask for a password. This is the account password you said you remember correctly. It should give you a output of seemingly random characters: this is the pass phrase to unlock the home partition.

I hope you still have that file backed up. Let me know if you run into any problems.