The Elevator Problem

[s1113645 at tesla.cc.uottawa.ca]

On Sun, 10 Dec 1995, Daniel Miskell wrote:

> There is an easy way to develop a secret key in front any number of eves, be 
> they experts or not, without the eves knowing what the key is.  Even if they 
> tap your phone/comm line, ect.  There was an article in Discovery Magazine a 
> couple of years ago, talking about how to use photons and their randomness as 
> the perfect, uncrackable code.  Use of the photons aside, there was a key 
> generation method discussed, simple, yet secure enough to work out on a tapped 
> phone.  Let me root around.

You must mean quantum crypto, by G. Brassard and C. Crepeau of U de Montreal.
Requires a direct fiber optic line from pt. A to B, in order to be 
secure, if I am not mistaken. Which makes it impractical for most people, 
as there are usually switches (or whatever they're called) and more than one 
line in between. Lets you use OTPs with your next-door neighbor though.