Zero knowledge in the real world?

[Written under the influence of QCSD] Not so long ago, I happened to watch the totally-accurate-in-every-possible-way film, “Travelling Salesman”. tl;dw: a squad of government-hired mathematicians are finally able to prove that P = NP, giving the state the power to answer every important computational question they can imagine (aka rob banks and fight terrorism). But … More Zero knowledge in the real world?