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From: mlm@nl.cs.cmu.edu (Michael Mauldin)
Newsgroups: sci.crypt,comp.misc
Subject: Re: public key encryption and RSA patent status
Message-ID: <25@nl.cs.cmu.edu>
Date: Tue, 15-Sep-87 13:36:58 EDT
Article-I.D.: nl.25
Posted: Tue Sep 15 13:36:58 1987
Date-Received: Sat, 19-Sep-87 15:27:12 EDT
References: <1372@osiris.UUCP> <441@polyslo.UUCP> <686@sugar.UUCP> <1490@epimass.EPI.COM>
Organization: Carnegie-Mellon University, CS/RI
Lines: 31
Keywords: RSA patent pencil paper bgofus
Summary: patent question about RSA
Xref: mnetor sci.crypt:545 comp.misc:1236


I agree with jbuck@epimass's assessment of the situation.  As I
remember it, you can't patent something that can be done (in principle)
by a person using pencil and paper.

Several months ago I posted a request asking just what about RSA the
MIT patent covers.  I got no answers.  It seems to me that they can be
patenting any of a number of things:

    o their special purpose hardware to perform RSA

    o their method of selecting primes (again probably only
      as it's imbedded in ROM in some hardware).

    o their specific approach to choosing primes and using
      exponentiation (their specific algorithm)

    o the general notion of using C = M^E mod pq

The first two would hold up, because you can patent a system with
algorithms embedded in it, but then the algorithm itself is not
necessarily protected.  The last two seem to violate the pencil and
paper test.

Not wanting to spend the time or money to ask the patent office for a
copy of the patent, I hoped I could find out on the net.  Does anyone
know specifically what the Patent was granted for/what they claimed?

Michael L. Mauldin (Fuzzy)		Department of Computer Science
ARPA: Michael.Mauldin@NL.CS.CMU.EDU	Carnegie-Mellon University
Phone: (412) 268-3065			Pittsburgh, PA  15213-3890