When you install Ubuntu Server 16.04, you have two encryption. You'll

This feature has been removed from the Ubuntu Server 18.04 installer.

On the Partition disks screen of either Ubuntu 16.04 or Ubuntu 18.04, you'll be given the chance to set up encrypted logical volumes for whole disk encryption:

After choosing this option, you will then be asked to enter a passphrase:

The disk encryption uses LUKS, just the same as we saw on the CentOS machine. To prove this, all we have to do is look for a populated crypttab file in the /etc directory:

donnie@ubuntu3:~$ cd /etc
donnie@ubuntu3:/etc$ cat crypttab
sda5_crypt UUID=56190c2b-e46b-40a9-af3c-4cb26c4fe998 none luks,discard
cryptswap1 UUID=60661042-0dbd-4c2a-9cf9-7f02a73864ae /dev/urandom swap,offset=1024,cipher=aes-xts-plain64
donnie@ubuntu3:/etc$

The home directory encryption of Ubuntu 16.04 uses eCryptfs, as evidenced by the .ecryptfs directory in the /home directory:

donnie@ubuntu3:/home$ ls -la
total 16
drwxr-xr-x 4 root root 4096 Oct 29 15:06 .
drwxr-xr-x 23 root root 4096 Oct 29 15:23 ..
drwx------ 3 donnie donnie 4096 Oct 29 15:29 donnie
drwxr-xr-x 3 root root 4096 Oct 29 15:06 .ecryptfs
donnie@ubuntu3:/home$

If you choose both options for Ubuntu 16.04, you'll have encryption on top of encryption, for double protection. Is that really necessary? Probably not, but choosing to encrypt my home directory ensured that the access permissions for it got set to the more restrictive 700 setting, rather than the default 755 setting. Be aware, though, that any user accounts you create now will have wide-open permissions settings on their home directories, unless, that is, you create user accounts with the encryption option. Also be aware, as I said, that using eCryptfs to encrypt your home directory is no longer an option in the Ubuntu 18.04 installer. With that said, let's get some hands-on practice with this next lab, which assumes that your hard drive isn't encrypted with LUKS.