Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!bcm!dimacs.rutgers.edu!aramis.rutgers.edu!remus.rutgers.edu!utopia.rutgers.edu!wilmott From: wilmott@utopia.rutgers.edu (Ray Wilmott) Newsgroups: comp.sys.atari.8bit Subject: Re: Copy protection (was Re: M.U.L.E. Sorrow!) Message-ID: Date: 28 Feb 91 02:18:12 GMT References: <1991Feb21.000558.15650@dhw68k.cts.com> <39563@cup.portal.com> <1991Feb25.022602.10895@uokmax.ecn.uoknor.edu> <1991Feb25.054200.4817@uokmax. Organization: Rutgers Univ., New Brunswick, N.J. Lines: 33 -- >It was incredible how almost incomprehensible the code was; 25 or >so pages of self-modifying, self-decrypting, partially-resident and >partially loaded from disk security checking. Pretty clever... Reminds me of the time I tried to decode Alternate Reality (still my fave Atari game...anybody still into it?) The City way back in '84 or so. Aside from wanting to "crack" it to make a backup, I mainly wanted to cheat and get a looksy at the imbedded text blocks of the game. The copy protection started by looking for a flawed sector. Easy to take out. Then there was the loading and decrypting of a few sectors (load 'em, EOR each byte with some number and store the result somewhere, then jump and execute the resulting code). Cute, and again pretty easy. Then that resulting code used a chained decryption scheme on a bunch of other sectors (read a byte from disk, EOR it with some memory location, add something else to it, EOR it with something else, then store the result in a memory location based upon some formula, then execute the resulting code). This one was annoying, but do-able. This chunk of code then did the same sort of thing, but with a much more complex set of formulas to decrypt and lots of jumping back and forth between subroutines. What a mess. I gave up. Kinda strange that they'd go to such lengths to more or less annoy hackers and pirates (ie-rather than just go all out to start with, they start simple and draw you into each more complex level of protection). BTW, did anyone out there ever "crack" this game and extract the text encrypted within sides 3 and 4 of the game? If so, I'd love to hear from ya...always wondered if there were more hidden things I hadn't discovered within the game... -Ray