PROG challange: fetish corroborator

write an algorithm that enables two persons over a communication channel to find out which fetishes from a preset list they happen to share.

it should done in such a way that no extra information is leaked, see http://en.wikipedia.org/wiki/Yao%27s_Millionaires%27_Problem to get started.

Bonus: Extra points are awarded to written in Lisp or Scheme.

Deadline: The deadline is 03/07/2015 so get cracking!

it's theoretically broken if one of them is dishonest (they could just pretend they have every fetish).