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From: ralph@ee.brunel.ac.uk (Ralph Mitchell)
Newsgroups: net.micro
Subject: Re: Copy Detection Protection
Message-ID: <358@brueer.ee.brunel.ac.uk>
Date: Mon, 28-Jul-86 09:37:52 EDT
Article-I.D.: brueer.358
Posted: Mon Jul 28 09:37:52 1986
Date-Received: Tue, 29-Jul-86 03:05:26 EDT
References: <2366@brl-smoke.ARPA> <449@sunybcs.UUCP> <6969@utzoo.UUCP>
Reply-To: ralph@ee.brunel.ac.uk (Ralph Mitchell)
Organization: Dept of EE & E, Brunel University, Uxbridge, U.K.
Lines: 39

In article <6969@utzoo.UUCP> henry@utzoo.UUCP writes:
>> Putting the serial number on a diskette is useless.  It wouldnt even
>> matter if it was encrypted, because all somebody has to do is get a hold
>> of 2 copies of the program, and compare the two files.  Where they differ,
>> that is where the serial number lies, and that is where you can change
>> it to whatever you wish.
>
>I think the intent of the original suggestion was to protect against
>casual copying, not determined and systematic piracy.
>
>If you feel mean, put a whole bunch of different stuff on each diskette,
>and bury the serial number *and a checksum* somewhere in the middle.


I don't suppose it would be practical to encrypt the entire disk, using
the serial number as the key ??  That way two original disks would look
entirely different, except for the decrypt program.  In fact, you could
probably generate 5 or 10 (or 50, if you're bloody-minded) ways of doing
the decryption, so pirates would have to acquire a significant number of
originals, just to be sure they get a matching pair...

Of course, the software house doesn't have to put the decrypt program in
the same place on all the disks. :-) :-)

Disclaimer:  So far as I know, the above suggestions do not apply to any
copy protected software currently available.  If that is true, I hereby
place this information in the Public Domain, so there ! :-) :-)

Ralph Mitchell

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