(NSA has been making noises about how they'd already discovered public key crypto years before Diffie and Hellman did. This could be face-saving bragadoccio. Time will tell. Any NSA readers out there are free to post anonymously to this group or to alt.whistleblowers, or to "sell" your memoirs on BlackNet.) There was an interesting discussion on this point at the ACM Conference on Computer and Communications Security a few weeks ago. At the ``Festcolloquium'' in honor of Gus Simmons, someone who used to work for NSA (his name escapes me, but I have it at home) stated that in 1963, President Kennedy signed a memorandum calling for -- in today's language -- the use of digital signatures for nuclear weapons command and control. The memo -- National Action Security Memorandum (NASM) 160 -- is still classified. Someone else on this list (I'll let him speak for himself) has contacted the JFK library about it. It may already be going through clearance release; if not, forms have been submitted to initiate the release process. And there's always FOIA if that fails. It will be very interesting to see the memorandum when it comes out. (Btw, it was written by Jerome Weisner, Kennedy's science advisor.) A lot of wisdom consists of asking the right questions; if the phrasing was right, I would tend to believe that NSA did indeed have public key technology in the mid-60's, once they were asked to create something with those properties. But if that was true, why didn't Simmons himself know of it? He said that he learned of public key from the Martin Gardener column in Scientific American, as I recall. Simmons was familiar with NASM-160, though; in fact, he was the one who supplied the number. --Steve Bellovin