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From: roy@alanine.phri.nyu.edu (Roy Smith)
Newsgroups: comp.sys.mac.programmer,comp.protocols.appletalk
Subject: Idea for painless copy protection
Message-ID: <1991Jan27.144523.20674@phri.nyu.edu>
Date: 27 Jan 91 14:45:23 GMT
Sender: news@phri.nyu.edu (News System)
Organization: Public Health Research Institute, New York City
Lines: 39


	Let's say I wanted to market commercially a Mac program and have
some way to discourage pirating.  Copy protection is out, since it doesn't
allow for backups, or lost/damaged distribution media.  But, what if I did
the following?

	When the program starts up, it installs something which listens for
broadcast packets to a specific port (my knowledge of appletalk is sketchy,
but this is easy to do in IP and I'm assuming AT has some similar
mechanism).  The program then sends out a broadcast packet to that port and
listens for any responses.  The responses it would get back would contain
the serial number of other copies of the program installed elsewhere on the
same AT network.  If any S/N matched that of this copy, it would refuse to
run.

	Let's not get into a philosophical debate about the ethics of
pirating and/or selling software, I'm just looking for comments on the
technical issues.  First, would it work?  Obviously, people could use
ResEdit to change the serial number, but I'm assuming that anybody who can
use ResEdit would find a way to get around any license scheme if they tried
hard enough; I'm out to get the casual pirater, the guy who buys one copy of
an application and passes it around the office/department/lab/classroom.  It
also wouldn't stop people from taking a copy home, but assume for the moment
that the application came with an enlightened license (like the one that
comes with Think C) which explicitly allows you to install it on two
machines as long as there is no chance both copies will be in use at the
same time (I interpret that as meaning it's OK to install it on both your
office Mac and your home Mac).

	Second, would it be a Bad Thing for the network?  I could see how it
might result in a flood of synchronized responses clogging the wire
momentarily, but it wouldn't be any different than how Inter*Poll interacts
with Responder, would it?  It would only happen once per launch, so I would
guess that would minimize the damage.
--
Roy Smith, Public Health Research Institute
455 First Avenue, New York, NY 10016
roy@alanine.phri.nyu.edu -OR- {att,cmcl2,rutgers,hombre}!phri!roy
"Arcane?  Did you say arcane?  It wouldn't be Unix if it wasn't arcane!"