From: strick -- henry strickland <strick@versant.com>
Date: Wed, 29 Sep 93 23:51:50 PDT
To: cypherpunks@toad.com
Subject: Files on DH, HM, RSA, & HP patents
Message-ID: <9309300651.AA01982@versant.com>
MIME-Version: 1.0
Content-Type: text/plain


I've been spending the week in Washington DC, so I went by the Public
Search Room of the U S Patent and Trademark office and requested the
complete files on the four patents named in rfc1424 (see below).

I have photocopies of nearly the complete folders, which include the
initial proposed patent and all the written communication between the
patent attorney and the patent examiner.  (I think all four of these
patents had all of their claims rejected on the first pass.)  You see
the patent examiner explain what is wrong, criticizing the patent, and
the subsequent ammendments and more rejections until the patent is granted.
(This is important information if one wishes to challenge a patent.  You
can see how various arguments were dealt with before and what likely
responses from patent examiners are.)

I'll bring all of this to the October Mountain View cypherpunks
meeting, assuming it is Sat Oct 9.  I'll also try and be ready to
summarize the history of each patent.  

What are missing from my copies are mostly legal communications that
had no techincal interest -- powers of attorney & calculations of
fees.   I also omitted most of the published articles that were
referenced (several other patents and some scholarly papers) and some
seemingly redundant diagrams.  Of course, I also have copies of the
final patents granted.

The Search Room is an interesting place.  I pulled several faux pas
and got quite an education in patents and federal offices....

			strick







-------------- excerpt follows --------------

RFC 1424        Key Certification and Related Services     February
1993


   The Massachusetts Institute of Technology and the Board of Trustees
   of the Leland Stanford Junior University have granted Public Key
   Partners (PKP) exclusive sub-licensing rights to the following
   patents issued in the United States, and all of their corresponding
   foreign patents:

      Cryptographic Apparatus and Method
      ("Diffie-Hellman")............................... No. 4,200,770

      Public Key Cryptographic Apparatus and Method
      ("Hellman-Merkle").................... No. 4,218,582

      Cryptographic Communications System and Method
      ("RSA")................................... No. 4,405,829

      Exponential Cryptographic Apparatus and Method
      ("Hellman-Pohlig").................... No. 4,424,414

   These patents are stated by PKP to cover all known methods of
   practicing the art of Public Key encryption, including the
   variations collectively known as El Gamal.