Can you bypass the protection of my game?

[mikaelt]

Hi

About 30 years ago I made and released a game on the Amiga. Last week I dusted of the disk and a friend made a ADF file.

I was so excited to run my forgotten old game. But when game starts it ask for a code matching the icon in the manual:



Bummer!

I have searched everywhere. I do not have the manual

In winUAE I have tried to look at the memory and ASM code - but it does not make much sense to me:





Is there anybody here in this forum skilled in areas of bypassing this kind of copy protection?

Here is the ADF file: https://mikaelthomsen.dk/images/Albert2.zip

Thanks in advance!

[Predseda]

I am absolutely sure there are masters of cracking so now the challenge starts who will break it first

[mikaelt]

Originally Posted by Predseda

I am absolutely sure there are masters of cracking so now the challenge starts who will break it first

Great! I'm so excited!

[ross]

Attached.

I have absolutely no idea what I cracked
Completely removed the page with the code request.

Cheers!

[coldacid]

Now we need to get the game translated, and a WHDLoad slave written.

[kriz]

Ross rulez

[mikaelt]

THANK YOU VERY MUCH ROSS!

That was quick! How did you do it?


Well, the game consist of some small games, where kids can learn to do math in, at that time, motivated and fun way.

Is also contains a small painting program.



(I have not yet lost my staggering art skills it seems )

The game was only released in Denmark (by a store chain called Betafon) and did not sell very well. But it was the very first time that I earned some money for coding a game - and I remember that I bought myself a sweater for that money.

To everyone: Feel free to use/change/translate the game as you like.

[gimbal]

"Slut". I love it. Every game needs a slut button.

[ross]

Originally Posted by mikaelt

That was quick! How did you do it?

Nothing special.
The only thing I think in this case makes the difference is the experience, which allowed me to do it in a short time.

What I did:
- with the debugger I found the loop in which the control code was checked (not so trivial for a casual user because the code compiled with AMOS is terrible ..);
- I could have simply made the program accept any code, but usually I am not very satisfied with this solution and if possible I try to go back to previous calls in order to completely eliminate the request screens;
- I went back in the code up to the point before the check page constuction and I made the actual crack (a full skip for the unwanted code);
- the problem is that code is compressed and therefore not immediately patchable with a hex edit (so you would never have succeeded on your own);
- then I went into the main code that call the general decompressor and trapped it so that it went into a my routine;
- I then found unused space in the executable and I injected my routine that performed the crack after decompression;
- being the decompression code called several times I used a flag to perform the crack only in case of need.

EDIT:
I reread what I wrote and it all seems simple, but maybe it is not..
In fact, I have no idea for a beginner how long it would take to crack this program.

[mikaelt]

Thanks ross for sharing

If you one day are up to it, you should record exactly what you did and share it on e.g. YouTube. I'm sure many people, including myself, would find it very interesting.

[Phantasm]

Originally Posted by mikaelt

Thanks ross for sharing



If you one day are up to it, you should record exactly what you did and share it on e.g. YouTube. I'm sure many people, including myself, would find it very interesting.

Flashtro.com has many cracking tutorials for lots of old Amiga games if you are interested. They mostly do assume a decent level of understanding of the low level Amiga and 68000 assembler though.

Sent from my XQ-AT51 using Tapatalk

[mikaelt]

Originally Posted by Phantasm

Flashtro.com has many cracking tutorials for lots of old Amiga games if you are interested. They mostly do assume a decent level of understanding of the low level Amiga and 68000 assembler though.

Sent from my XQ-AT51 using Tapatalk

Thanks! I'll check it out!

[mnemo]

Originally Posted by mikaelt

In winUAE I have tried to look at the memory and ASM code - but it does not make much sense to me:

You disassembled the ASCII text you found at $22CE24, but of course that's just gibberish. You need to disassemble code that references the text, i.e. find where there's a pointer to the text.

[mikaelt]

Thanks for explaining mnemo. I'm a total newbie in this stuff :-)