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Path: utzoo!linus!decvax!tektronix!hplabs!hp-pcd!john
From: john@hp-pcd.UUCP (john)
Newsgroups: net.micro.hp
Subject: Re: Orphaned Response
Message-ID: <77900008@hp-pcd.UUCP>
Date: Wed, 17-Jul-85 13:08:00 EDT
Article-I.D.: hp-pcd.77900008
Posted: Wed Jul 17 13:08:00 1985
Date-Received: Sun, 21-Jul-85 23:13:51 EDT
References: <566@alberta.UUCP>
Organization: Hewlett-Packard - Corvallis, OR
Lines: 37
Nf-ID: #R:alberta:566:hp-pcd:77900008:000:1515
Nf-From: hp-pcd!john    Jul 17 09:08:00 1985

< I think it is a kind of dumb idea - it would be VERY
< easy to hook up some sort of line-protocol analyzer on the 
< line and figure out what is being sent back and forth, and then
< build a little simulator that could fake it out...and the one
< you build would probably be significantly less expensive than
< the original unit!


Depends on how difficult you make the encoding scheme. If you used
an encryption scheme like DES with a unique serial # in each device
then it would be easier to disassemble the program rather than try
and break the protection. The program would pass a random # to the
hardware key and ask it to encrypt it using its internal number.
The program could then encode the same number and verify it. Even
a relatively weak encryption scheme could lock out 99 % of potential
copiers.
 

<  	I system I prefer is a hardwired serial number in the 
<  BIOS ROM of each PC - the program checks that and stores it,
<  encoded, in it's own code...


We do that on the Portable (AKA HP-110) and Portable Plus computers. A
program can read the serial # of the computer it is running on and decide
if it should abort or run. 

On of the best ways to copy protect software is to distribute it in ROM.
The 128K byte roms currently have a high enough mask charge to make small
numbers uneconomical to copy. Large volume cost more than floppies but
gives the user a product that can be quickly loaded and will not wear
out after X number of revolutions.


John Eaton

!hplabs!hp-pcd!john
#! rnew