It's pretty basic stuff. Say the equivalent of not using the default password your administrator gave you as far as configuring inter-server communication is concerned.
Now, if you do use TLS links and you do need to change it, get ready for an outage to do it, and make sure you lab it out 5 ways from Sunday first. But, spinning up a lab AES in VMWare, even if not licensed, should let you get the whole thing spun up to your CM. You'll be able to go encrypted stuff to the 3rd party apps and to CM, and if you got it right, you'll decrypt messages like "no capacity to do anything because you don't have a license!" and you'll know you nailed it!