Date   : Wed, 16 May 2001 09:47:26 +0100
From   : "Rich Talbot-Watkins" <rich@...>
Subject: Re: Locked and beyond

"C Davies" <davies_@...> wrote:

> Anyone else remember the fun of cracking the protections on the trusty BBC
> games?  I used to have a passion for doing this to transfer stuff to disc.
> Programmers used to leave little messages embedded in the files that you
> would unscramble on the way to cracking the games.

Yep, it was always fun, and I've not come across anything quite the same on
another platform since...

Gary Partis's protection systems always had little embedded messages
(normally threatening you with murder or something equally unsubtle).
Starquake had hundreds of little tiny loops which decrypted the next little
bit of code in a different way each time - and the only way I found of
cracking it (short of writing a fast interpreter to do the job for me) was to
decrypt every last one of them by hand... ouch.

> Aardvark left some message about stringing you up with chicken wire...

The other thing Orlando did (as he'd already played around with them in the
code for Zalaga) was write a straight ASCII message which contained loads of
undocumented opcodes, which just looked like gibberish code, and then
actually executed it - the exit values of the registers were then used as
inputs to the decrypter later on.  It completely threw me for ages and took
me ages to believe that it was actually genuine.

> And the ultimate protections were by Kevin Edwards.  They certainly made
you
> think...  I remember he left his mailing address in one game, after you'd
> got through most of the layers of protection, asking for people who got
that
> far to get in touch with him.

Kevin Edwards' protection systems always beat me unfortunately!  James Fidell
posted some code to this list a little while back which he wrote ages ago to
crack it - I was impressed.....

Exile was nice too.... contained its own implementation of the filing system
commands (via vector interception) which allowed it to read its oddly
formatted disc as if it were a normal DFS disc - but only if you'd hacked thr
ough the outer layers already!

Can't think of any more at the moment... anyone else?

Rich :)