As fuzzy-logic said, just don't reveal your total comp, and be willing to walk away from it for real (walking away from such juicy offers requires the most determination, so it's important you do it from a position of power, for example if you already have a good job, otherwise they have you by the balls).

The only case where it can be beneficial to disclose something about your compensation is if you have deferred compensation (e.g. stock options) that you want your potential new employer to somehow consider in the offer. In that case, sharing a copy of the grant is the easiest thing to do, and doesn't hurt much