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Smoking gun invalidates crypto patent

Finally!  Free public key crypto!

Rumors have floated for years that Diffie-Hellman patent is invalid 
because it was disclosed more than a year prior to the patent 
application. But it was never clear if Diffie or Hellman actually 
disclosed (in the legal sense) the invention. It would seem that Roger 
Schlafly has found a "smoking gun."  Through the legal discovery 
process, Schlafly found a copy of the "New Directions..." paper in the 
procession of an IBM researcher (Mike Matyas) with a stamped "received-
by" date more than a year before the patent filing. This copy did not 
have any confidentiality markings or indications of pre-publication 

Since Diffie-Hellman pre-dates Hellman-Merkle (the Knapsack patent), no 
one can assert any infringement of anything for the use of Diffie-
Hellman - it's free.

The real beauty of the patent system is that a patent holder has to 
defend validity no matter how many times it's challenged. So even if 
Schlafly should fail on a technicality, anyone else, an unlimited number 
of times, can challenge this patent again. (Note: One may question 
whether Stanford lied to the patent office about this. That's fraud.)

The following information is a matter of public record, direct from 
Schlafly's motion for summary judgment, dated October 16th, 1995.


3.    Diffie-Hellman is invalid because of a statutory bar.

3.1.  The Diffie-Hellman patent application was filed on Sept. 6, 1977.  
According to 35 USC 102 (b), the patent is invalid and unenforceable if 
there was a public disclosure prior to Sept. 6, 1976.

3.2.  A research paper by Diffie and Hellman, "New Directions in 
Cryptography", IEEE Transactions on Information Theory, vol.  IT-22, no.  
6, Nov. 1976, was submitted on June 3, 1976.  It discloses the secure 
cipher key generator of the Diffie-Hellman patent.  A copy of the paper 
is Am. Compl. Exhibit. U.

3.3.  A survey paper, "The First Ten Years of Public-Key Cryptography", 
was published by Diffie in Proceedings of the IEEE, vol. 76, no. 5, May 
1988. A copy of the paper is Am. Compl. Exhibit. V.  It states on p. 563 
that the Am. Compl. Exhibit. U paper was publicly distributed in June 
1976 and publicly disclosed at the National Computer Conference, also in 
June 1976.  That conference was open to the public, and well-attended by 
experts in the field.

3.4.  A true and correct copy of the "New Directions" preprint dated 
"August 1976" attached as Exhibit. CA.  It contains a full disclosure of 
the Diffie-Hellman invention.  Schlafly received it from the files of 
Mike Matyas, a cryptographer at IBM, on May 8, 1995.

3.5.  Hellman also lectured on the subject at the 1976 International 
Symposium on Information Theory, Ronneby, Sweden, June 21-24, 1976.

3.6.  The PTO was not informed of these prior art disclosures, as there 
is no record of them in file wrapper.