How to make a content highly secure?

Example : Consider I have an navbar and that navbar as a button which should be available to use only when the user is authenticated. Now, here I can use dmx-show or dmx-hide dynamic attributes based on the server connect of the authenticated user details. But I don’t seem to find them very secure since they are hidden using the css properties, which are easily editable.

So, is there any other way to literally hide a content from even appearing in the code ?