🚀 go-pugleaf

What follows is a rather obvious generalization of a well-known idea by
Sloane on how to foil an eavesdropper who has a noisy channel. Save this
article---this will prevent anyone from patenting the idea in the
future.

In tomorrow's high-speed networks it will be possible to overwhelm a
typical listener's expected ability to record a lengthy message. So
imagine two parties, X and Y, sharing some information. X and Y exchange
a large amount of data, more than an listener can be expected to record;
both X and Y compute on the fly a function of the data which depends on
the shared information. Unless the listener has enough knowledge of the
shared information to attack the system by brute force, he will never be
able to figure out any information about the value of the function,
provided of course that the data and function are cryptographically
strong. X and Y can exchange any amount of data this way, perhaps for
later use as a one-time pad, subject only to the capacity of the
network.

Notice that the initial shared information need not be perfectly secure.
It could even be publicized after it's used! The listener can, at best,
attempt to compute the function of the data simultaneously for all
possible values of the shared information, and if the shared information
comes from a sufficiently large space then this will be impractical. The
shared information could even have been transmitted by a weak
cryptosystem, provided that the listener is not able to break that
system before being flooded. So flooding can turn a weak cryptosystem
into a strong cryptosystem.

---Dan