As with most questions about the Freemasons, the only people who know the answer for sure probably won't tell you. There has been a lot of speculation about this lately. The Masons themselves officially deny that there is a secret Masonic handshake, but well, they would, wouldn't they?

Actually, even if such a handshake existed in the past, they would certainly have stopped using it or changed it by now, because with all the public interest, examining of footage of famous Masons etc, too many people would have managed to work it out!

The story you usually hear is that it's like a regular handshake, but the thumb discreetly presses between the base of the second and third fingers. But if it was as easy as that, everyone would know how to do it, so I'm quite sceptical. Still, you could always experiment and see what happens. You hear stories off people 'accidentally' doing a Masonic handshake and getting let off a speeding fine or whatever, but I'll start believing these rumours when somebody provides a little proof.