From: Matthew J Ghio <mg5n+@andrew.cmu.edu>
Date: Wed, 20 Oct 93 15:12:39 PDT
To: trebor@foretune.co.jp>
Subject: Re: Wizardry crypto
In-Reply-To: <9310200948.AA07977@dink.foretune.co.jp>
Message-ID: <4glPONa00VpLIvm0ZH@andrew.cmu.edu>
MIME-Version: 1.0
Content-Type: text/plain


"Robert J. Woodhead" <trebor@foretune.co.jp> wrote:

> Not much to do with encryption, but Wizardry encrypted it's
> game strings with a simple system that nobody broke (I guess
> tracing p-code was too much trouble).  It added X*the character
> position and Y*the line number+Z*the previous character, as I recall...

Yeah, that worked pretty well, considering that most people just looked
for text by scanning it with a sector editor.  Encrypting the text made
it undistinguishable from the program code.  Tracing the program code
would have been difficult, considering that it was written in the
original Apple pascal, which used a token compiler (I think).  But,
alas, the character files were in plaintext, and numerous people figured
out how to edit them.  So were the items and monsters.  One day when I
was very bored, I managed to decipher the maze data, and was then able
to build a map of the 10th level where dumapic didn't work.  As I
recall, it was just 2 bits to define each section of wall, arranged in
four groups of data defining each of the four directions, followed by
another block of data which used nybbles to define what was found in the
blocks created by the intersections of the walls.

One thing that I was able to break was the code book that was the
copy-protection for Return of Werdna.  As I recall, it was calculated in
base 9 (or some sort of nine number system which used the digits 1-9 but
excluded zero).  Once I realized that, breaking the code was just a
matter of simple arithmetic.  It was an interesting excercise in
code-breaking tho, and I did it without disassembling the program.
I must say that this was preferrable to the copy-protection in the
original Wizardry, in which my master disk eventually wore out from
overuse and developed bad sectors.  Gee...All this nostalgia has made me
want to play again.  It's a fun game, and the 3-D system was pretty
innovative for the time.  Does Sir-Tech still replace bad disks (from
the Apple II version)?