[wyclif]

I tell them: "We both know that how much I am currently paid has absolutely nothing [emphasis in tone] to do with how you decide to compensate me."

This lets them know two things: 1. You're not going to divulge your current pay no matter what, and 2. Gives them a face-saving 'out' by complimenting them that their company is "different" and special (and makes it sound as if your compensation is totally their decision; the negotiation over a number has not begun yet).