Using lasers to communicate

[Lou Poppler]

} At 10:38 AM 2/14/96 -0500, you wrote:   [i.e. lwp at mail.msen.com == me]
} >
} >Eavesdropping and channel-blocking and physical-location-discovery are 
} >related threats to which most traditional data channels are susceptible.  
[snip]
} >larger mirror.  Then (under computer control) the various small mirrors
} >on the laser table are rapidly inserted and withdrawn from the light beam,
} >causing the laser beam to follow first one path, then another, then another
} >through the (smoky) air -- all to the delight of the audience.
} >
} >This technology could easily be adapted to make a communication channel
} >safer from the various threats of eavesdropping, interruption, and tracing.
} >A single point-to-point channel could be made to follow various paths 
} >having common elements only VERY close to the endpoints.  Better still,
} >a network of more than two nodes could be constructed without needing to
} >provide multiple transceivers at each node (and with possibly multiple 
} >beam paths between each pair).  With known methods of routing and
} >collision avoidance, we could thus not only route around any known opposition
[snip] 

On Fri, 16 Feb 1996 00:03:38 -0800, gw <geeman at best.com> wrote:

} KNOWN opposition ... hmmm.  you're back to obscurity=security.
} It's always expensive to eavesdrop (tapped any fiber cables in pressure
} jackets recently?) ... 
[snip]

I was also thinking about security by redundancy.  It is fairly 
inexpensive for an opponent simply to cut a fiber run.  The scheme
I'm talking about allows you to provide additional signal paths much more
cheaply than the opponent can interrupt them.

::::::::::::::::::::::::::::::::::::::   "He who buys for price alone is
:: Lou Poppler <lwp at mail.msen.com>  ::     [the suits'] lawful prey."
::      http://www.msen.com/~lwp/   ::  
::::::::::::::::::::::::::::::::::::::     --  John Ruskin