🚀 go-pugleaf

In article <686@sugar.UUCP> peter@sugar.UUCP (Peter da Silva) writes:
>> [...public key encryption...prime numbers...]
>
>Sounds like  you'r talking about RSA public key encryption. This technique
>is patented by Rivest, Shamir, and Adelman (? did I get these names right?).
>
>Therefore there is not now nor will there ever be (until the 17 or so years
>is up, anyway) a public domain implementation of this.

There is public-domain code (Dr. Dobbs' Journal and other places);
whether it's legal to use is another matter.

There are other number-theoretic public-key algorithms out there.
Also, it's not clear to me that the RSA patent could withstand a
well-financed challenge in court, and I suspect it will be thrown out
eventually.  The way the patent laws were set up, you can't patent a
discovery or a mathematical truth.  Until recently algorithms were
considered unpatentable since they were seen as mathematical laws.
There's a lot more than that to real software.  But RSA is a
straightforward application of Euler's Theorem.  Also, R, S, and A
didn't come up with the core concept of public-key encryption -- a
"one way" transformation.  Their contribution was to recognize a new
way in which to use 200 (or more)-year-old number theory.  Unless the
license fees are kept very reasonable and low, the patent will be
challenged and ruled invalid in the near future.  

A patent gives the patent holder grounds to sue someone who infringes
on it.  The government will not enforce the patent.  It does not give
a guarantee that the patent holder will emerge victorious; frequently
the patent holder emerges without the patent (because it is ruled
invalid).  

>If anybody knows anything about any of the non-patented public key systems,
>(knapsack?), please post a followup.

The knapsack approach has been broken; fast ways of solving knapsack
problems are now known.


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