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From: mcdonald@uxe.cso.uiuc.edu
Newsgroups: comp.edu
Subject: Re: File-wise Copy Protection for Labs
Message-ID: <51200003@uxe.cso.uiuc.edu>
Date: Fri, 25-Sep-87 09:55:00 EDT
Article-I.D.: uxe.51200003
Posted: Fri Sep 25 09:55:00 1987
Date-Received: Sun, 27-Sep-87 11:04:53 EDT
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Nf-From: uxe.cso.uiuc.edu!mcdonald    Sep 25 08:55:00 1987



>/* ---------- "File-wise Copy Protection for Labs" ---------- */
>We would like to be able to distribute disks to our microcomputer labs with
>specific files protected against copying.  I am familiar with several

This CANNOT be done! If a disk can be read, it can be copied! The worst 
possibility is that you might need a $100 hardware addon. Even the
disks with laser damage can be copied (complete with laser damage; you just
need to get the laser, which probably exist around any big university.)
Even trying this in an academic environment is simply am invitation to
students to spend all their time breaking your scheme. You could try to
encrypt your files, but then someone would only have to copy the decryptation
program. If someone tried it around here, someone else would spend a couple
of hours of Cray time breaking the code.

Doug McDonald
University of Illinois