Subject: Re: The Pledge model -- K5 generates 6 mos income in three days
From: "Stephen J. Turnbull" <>
Date: 27 Jun 2002 14:14:53 +0900

    Ian> "Stephen J. Turnbull" <> writes:

    >> And _some_ software (RSA comes to mind) is sufficiently hard to
    >> reimplement from the spec (Diffie- Hellman IIRC) that making it
    >> proprietary always makes business sense.

    Ian> RSA is easy to implement if you understand number theory.  I
    Ian> did it once in about a month,

Starting from _Diffie-Hellman_'s public-key algorithm as the spec?
You're even smarter than I thought already![1]

_Anything_ is easy to implement (in this sense) once the algorithm is
published.  The point is that, given the patent (== the relevant form
of "making it proprietary" in this case), RSA had a couple of years
lead before implementations of D-H that did not violate even the
patent's narrowest claims (ie, w.r.t the specific number-theoretic
algorithm implemented in RSAREF inter alia) appeared.

This is in general _not_ going to be true for menuing or "business
process" patents (except for the PTO's willingness to grant
excessively broad patents).  There, even a vague spec is likely to
give a good architect enough hints to implement something as good or
better than the original.  And even with the PTO, most of those
patents are only good for racketeering: "you're right, given your
rather different implementation, _we_ aren't going to win in court,
but the legal fees will bankrupt _you_ first."

[1]  And that ain't damning with faint praise, either, No, Sir!

Institute of Policy and Planning Sciences
University of Tsukuba                    Tennodai 1-1-1 Tsukuba 305-8573 JAPAN
 My nostalgia for Icon makes me forget about any of the bad things.  I don't
have much nostalgia for Perl, so its faults I remember.  Scott Gilbert