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From: stuart@bms-at.UUCP (Stuart D. Gathman)
Newsgroups: comp.misc
Subject: Copy "Protection"
Message-ID: <470@bms-at.UUCP>
Date: Wed, 5-Aug-87 11:10:44 EDT
Article-I.D.: bms-at.470
Posted: Wed Aug  5 11:10:44 1987
Date-Received: Sat, 8-Aug-87 06:00:44 EDT
References: <6965@ism780c.UUCP> <1193@killer.UUCP> <776@cod.UUCP>
Organization: Business Management Systems, Inc., Fairfax, VA
Lines: 22
Keywords: Serial Numbers
Summary: The reasonable alternative


The best method of protection for publishers I have seen is the serial number.
Every copy has a unique serial number.  This in no way prevents a user from
making as many copies as he wishes and using them as he wishes.  It does,
however, let the publisher demonstrate wrongdoing when a serious offense
occurs.  (What?  500 copies with the same serial number?!)

Encryption is usually used to make changing the number difficult.  But even
if the number is changed, it is difficult to pick one that does not belong
to someone else, or has not yet been issued!

When it is too expensive to manufacture the media with serial numbers, many
companies let the user apply the serial number.  A serial
number and encrypted key are supplied with the product on a sheet of
paper.

This method is particularly effective when the publisher has records of
which numbers go with which customers, i.e. most users register their
purchase.
-- 
Stuart D. Gathman	<stuart@bms-at.uucp>
			<..!{vrdxhq|dgis}!bms-at!stuart>