Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!rutgers!mit-eddie!genrad!decvax!decwrl!labrea!glacier!jbn From: jbn@glacier.STANFORD.EDU (John B. Nagle) Newsgroups: sci.crypt Subject: Re: New PubKey System Coming Message-ID: <13887@glacier.STANFORD.EDU> Date: Fri, 2-Jan-87 13:40:02 EST Article-I.D.: glacier.13887 Posted: Fri Jan 2 13:40:02 1987 Date-Received: Fri, 2-Jan-87 21:00:16 EST References: <3859@utcsri.UUCP> Organization: Stanford University Lines: 29 Summary: Is the algorithm being disclosed? Is the patent out in any country yet? I'm interested in seeing how it works. A patent number for any country would be appreciated. In any case, these things can't be considered secure until they've stood considerable scrutiny. Always remember Friedman's remark, "No new cypher is worth looking at unless it comes from someone who has already broken a very difficult one." The big problem with public key systems is that one needs some suitable function whose inverse is enormously harder to compute than the function itself. The two functions most discussed to date are the knapsack problem and the factorization of large numbers, and advances in mathematics have made both problems much more tractible in the last few years. If someone has a new function, it may be a significant step forward. Or it may not. One would like a problem with a provable lower bound, but the theory of lower bounds is very weak as yet. With the advent of good, fast, modem technogies, and good voice digitization and compression schemes, the use of digital encryption for voice over voice-grade lines without serious loss of quality is already possible. If this new scheme works, one could produce secure telephones for consumer use which would automatically exchange public keys at startup and then go to encrypted digital mode when talking to another of their own kind. This sounds expensive and complicated, but it will eventually come down to one chip with a small number of pins. This has definite product potential. Let's hear more details about the technology. John Nagle John Nagle