The very idea of a "user" is, in every phase of Latin that I know, gobbledygook. There's no translation for it. It makes as much sense as "haver" would make to us ("haver of what?"). Maybe "emptores" (buyers)? Sort of?

"Data," in our sense, too, sounds wrong to me as a concept in Classical Latin -- too disembodied for effective, accurate translation. Maybe 'cognoscenda,' "that which is to be known/understood," would come close to the intended sense and still be somewhat idiomatic.

"Vera" or "verita" sounds, to me, like the right language for the idea of "something true."

And like I said, "defendo" sounds like the right verb.

The omission of conjunctions sounds as abrupt, curt, and pompous in Latin as it does in English: "guard the user, the data, the truth." Only Sallust and Tacitus get to write this way.

So maybe we could correct it to something like "defende emptoresque cognoscendaque veraque?" No, actually, I take it back. That sounds deranged and wrong, kind of like the raving you might hear from one of the street-corner prophets in Life of Brian. Protecting those things makes no sense, and even the grouping of those three concepts in a single list makes no sense. It sounds like the product of a disordered, unhealthy mind.