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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.crypt
Subject: Re: RSA cryptographic algorithm patented?
Message-ID: <5828@utzoo.UUCP>
Date: Thu, 25-Jul-85 16:22:45 EDT
Article-I.D.: utzoo.5828
Posted: Thu Jul 25 16:22:45 1985
Date-Received: Thu, 25-Jul-85 16:22:45 EDT
References: <9028@ucbvax.ARPA> <490@calmasd.UUCP>, <1975@ukma.UUCP>
Organization: U of Toronto Zoology
Lines: 29

> I agree.  You can't patent an idea, just the implementation.  If you wrote
> your own RSA program, you certainly wouldn't be breaking any laws, just as
> if you wrote your own Unix kernel, you could sell it freely.

Sorry, you're confusing several different forms of protection.  The Unix
kernel is protected by trade secret, and independently re-implementing it
is legitimate.	You can come up with the exact same code, in fact, provided
you can prove that you didn't steal it from AT&T.  (In practice, making
the code distinctly different simplifies this proof a lot.)

Copyrights (e.g. the one on the Unix manual) protect the form in which
concepts are expressed, and so you can re-use the concepts *provided*
you express them differently.  A book which is word-for-word identical to
"Lord of the Rings" is a copyright infringement even if you come up with
it completely independently.  But you can re-express the same ideas without
any problem.

Patents are different; they *do* protect ideas rather than the form in
which the ideas are expressed.  Furthermore, even independent invention
of the idea is not a defence against a patent-infringement suit.  If the
patent on the RSA algorithm holds up -- patenting algorithms is a gray
area -- then *all* implementations of the algorithm are covered.

By the way, don't forget that the Unix kernel includes the patented
setuid bit, although AT&T has (as I recall) waived royalties on this.
Yes, the idea of the setuid bit is patented.
-- 
				Henry Spencer @ U of Toronto Zoology
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