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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: sci.crypt
Subject: Re: encryption with public keys
Message-ID: <7450@utzoo.UUCP>
Date: Mon, 29-Dec-86 21:28:28 EST
Article-I.D.: utzoo.7450
Posted: Mon Dec 29 21:28:28 1986
Date-Received: Mon, 29-Dec-86 21:28:28 EST
References: <3072@ihuxf.UUCP> <9001@duke.duke.UUCP> <7447@utzoo.UUCP>, <230@gaia.UUCP>
Organization: U of Toronto Zoology
Lines: 30

> Henry, do you have any idea just what is patented? ...

Not in detail.  I believe they actually succeeded in getting a patent on
the basic idea of RSA encryption, not just on a specific implementation.

> ... I wonder if a system to do fast modulo exponentiation
> would be verboten?

Not unless you use it to do encryption! :-)  More seriously, I doubt that
the RSA patent covers encryption using large-number arithmetic in general;
it's just the specific scheme using two big prime factors and their product
for encryption that's patented, I would guess.

> Sadly, patents are getting pretty ridiculous these days;
> algorithms are not supposed to be patentable, so what is RSA encryption but
> an algorithm? ...

One can argue that it's not exactly an algorithm, but that's pretty thin ice.
More to the point, the idea of being unable to patent an algorithm was always
pretty silly:  the whole idea of patents is to protect useful inventions, and
a useful new algorithm, solving a significant problem in a novel way, would
certainly seem to fit an intuitive definition of "invention".  The fuss about
algorithms resulted, as I understand it, from confusion with the natural-law
exclusion (patenting something "invented" by nature is obviously silly, but
there is no occurrence of RSA encryption in nature!) and the fuzzy boundaries
between science, mathematics, and computer "science" (which is primarily an
engineering discipline, whose inventions should obviously be patentable).
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,decvax,pyramid}!utzoo!henry