Encrypt Transmitted Data Whenever Possible

Description

Data transmitted over a network, whether wired or wireless, is susceptible to passive monitoring. Whenever practical solutions for encrypting such data exist, they should be applied. Even if data is expected to be transmitted only over a local network, it should still be encrypted. Encrypting authentication data, such as passwords, is particularly important. Networks of Ubuntu 18.04 machines can and should be configured so that no unencrypted authentication data is ever transmitted between machines.