From: derek@cs.wisc.edu (Derek Zahn)
Date: Tue, 21 Sep 93 13:52:42 PDT
To: cypherpunks@toad.com
Subject: Re: Why RSA?
Message-ID: <9309212049.AA00561@lynx.cs.wisc.edu>
MIME-Version: 1.0
Content-Type: text/plain


First, the ViaCrypt version:  I realize that it is legal.
It's also very expensive when compared to the price of
email readers/composers that people normally use (often
weighing in at about $50 / seat).  A $200 add-on is not
likely to be universally accepted.  It's as if somebody
had patented car door locks and claimed that $40,000 was
a reasonable price to have them included on a $10,000
car.  I'm not complaining about the price; people can
charge whatever they want for their products.  However
it does seem kind of high, creating market pressure...
that market pressure surfaces in messages like this one
and hopefully someday competing products from somebody.

Perry Metzger:

> All are patented in so far as one of the patents covers ALL public key
> schemes. Some, like Rabin's scheme, have possible technical advantages
> over RSA.

I am just beginning to study the mathematics behind public
key crypto (got Simmons's _Contemporary Cryptology_ from
the library this morning), but I haven't seen anything
about what exactly this means (that is, I haven't been
able to "look it up").  I was under the impression that
many people participated in the development of P.K.Crypto...
how can somebody patent all of their work?  Don't these
kind of patents apply only to specific algorithms?  Begging
the indulgence of this list, two more questions:

* is there a reference I can read that covers the scope of
  public key crypto patents?

* in broad terms, what would I have to do to develop an
  algorithm that works from a user's perspective like
  p.k.c. (ie public/private keys, the central functional
  point of all the wonderful schemes based on pkc) but
  doesn't violate patents?

Thanks!

derek