$ecrypt-unwrap-passphrase
you want to acquire this mount passphrase at a later date, just run the
ecryptfs-unwrap-passphrase command while logged in.
You can still recover your encrypted files without this mount passphrase,
assuming the ecryptfs wrapped passphrase is still available on your hard
drive. However, if you lose this data or it becomes corrupted, you’ll need
the mount passphrase to recover your files.
http://www.howtogeek.com/116297/how-to-recover-an-encrypted-home-directory-on-ubuntu/
