Learn English – What do you call someone who doesn’t know how to swim

You may want to use oblivious.

Consider that fine word obscurantist (“A practitioner of obscurantism; an obscurant”), where obscurantism has a sense “being deliberately obscure or vague”, and obscurant as an adjective means “Acting or tending to confound, obfuscate, or obscure”, or as a noun, “One who acts to confound or obfuscate; an obscurantist” or “A person who seeks to prevent or hinder enquiry and the advancement of knowledge or wisdom; an agent of endarkenment”. The latter phrase also suggest the term endarkener.

Note, by the way, that “security through obscurity” (a general term for keeping things secret by hiding them) often is denigrated as a security policy.