For those of you without any experience with the C-64, let me describe a component that is paramount to this next story. The C-64 had a built-in BASIC interpreter. So, you could just turn it on, and start typing a BASIC program in, and run it. As anyone who has done ancient BASIC could tell you, protecting a program that must be in unpacked, unencrypted form is nearly impossible. Being that the default operating mode of the C-64 was in "Enter BASIC code" mode, there were some things that programmers did to try to protect their code. The Commodore had commands that could change the background color, change the text color, clear the screen, those kinda things. Well, the programmers would embed comments (REM statements) in their code that did things like change the text color to be the same as the background color. Or embed CLEAR SCREEN commands so that you would get a line of code, and then the screen would clear before you could read it. This worked pretty well on the screen, but if you printed it out, all protection was lost.
So, a couple of companies introduced what was called "BASIC Compilers". These were just programs that changed the BASIC keywords into their appropriate tokens, and then called the build in BASIC to execute those tokens. This sped up your code, as it allowed the compiler to convert ALL the keywords into tokens at compile time, and at runtime, it just funneled them into the interpreter, thus speeding things up. The 2 companies that made these products were Commodore who made their own called "PetSpeed", named after the Pet computer which preceded the VIC-20, and Skyle's Electric Works produced one called "Blitz!". And these afforded SOME amount of protection to programmers for a while.
There was a company that produced a copy protection that was written in BASIC, and compiled with PetSpeed. This product was called "Deadbolt 64". It was sold in the back of ALL of the Commodore magazines. Some of the smaller software publishers fell for this, and bought it to protect their games. In case you haven't determined it yet from reading my OTHER posts, off the shelf copy protection is most often a BAD idea, as once it has been cracked, the crack works for most everything that uses it. This was the case for Deadbolt 64.
When I first saw it, I was SHOCKED that anyone would do protection in BASIC. But, when I began to look around, and see that there weren't any "decompilers" for PetSpeed like there was Blitz! it began to make sense. So, with no other tools at my disposal, I began to "Shotgun it". This involves loading the code into memory, and blanking out segments of it with 00's, and then running it to see what happens. It was with this technique that I found the section of the code that did the disk check, and made the decision on if the results of that check were good. Painstakingly I narrowed it down to 1 byte that had to be changed to 00 to crack deadbolt. From that time on, when I got a deadbolt 64 protected game, I would change that 1 byte, and it would be done. Always the same byte, in always the same place. How handy! So, with this technique in place, I felt I was set for any deadbolt 64 game.
In the summer if '85 the "Commodore Association Southeast" CASE show came to Nashville. It was at this show that I met Jim Butterfield, and some other Commodore dignitaries. I also met the guys selling a product called "Superkit 1541". Which was a new copy program for the 64. We hung around their booth, and talked to them about cracking and the like. (As the authors were 2 very good, and very notable crackers "The Goose" and "The DOD".) We were hanging out when a guy who had written 2 adventure games came by to taunt us for not being able to copy his games. Matter of fact, he was SO sure, he loaned us copies of the games, so that we could try to copy them, and fail. Yeah, you see this coming, they were protected with Deadbolt 64. One of the games was entitled Krakatoa. When I cracked it using my 1 byte method, one of my friends began saying that his game had been "Krakatoa'ed". :-)
This guy (the author), didn't realize that he was walking into the lion's den when he did that. We were NOT the people you wanted to challenge. He had not only drank the Deadbolt kool-aid, he had went back for 2nds, and maybe even 3rds. (As they no doubt told him that there was NO WAY it could be copied, or cracked).
Saturday, August 9, 2008
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