Encrypting entire partitions is cool, but you might, at times, just need to encrypt an individual directory. For that, we can use eCryptfs. We'll need to use our Ubuntu machines for this, because Red Hat and CentOS no longer include eCryptfs in either version 7 or 8 of their products. (It was in Red Hat 6 and CentOS 6, but it's no longer even available for installation in version 7 or 8.)