Learn English – What would you call someone who makes no lasting impression

In the abstract, I would go with operator. If you wish to put this together with the type of requests that the person has to answer to, you could probably say handler.

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.