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Ask HN: Help me hack my 30 year old shareware game

2 points by Rabidgremlin ↗ HN
So I recently found the binaries for a shareware game I released almost 30 years ago. Unfortunately I don't have the source code so cannot generate the "key" to unlock all the levels of the game. I'd like to put the unlocked game up on the web.

You can play the game here: http://play.rabidgremlin.com/gridlok/ (I'm pretty amazed you can play an old DOS game in a web browser) and download the game's files here: http://play.rabidgremlin.com/gridlok/gridlok.zip

The .zip file has GRIDREG.EXE which was used to create the unlock key. Also I guess it would also be possible to patch GRIDLOK.EXE so that it thinks it's registered.

Figured it might be a fun challenge for someone out there!

12 comments

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sigmaprimus
Did you create this game? You said that you released it but that is different. If You did create it and just lost the source, what language and or IDE did You use to write it?
Rabidgremlin
Teenager me did create this game. It was created using Turbo Pascal. Probably v5.5 or maybe 6.0. Also had a bunch of ASM mixed into the code for speed.
[deleted]
(comment deleted)
ksaj
Depending on the actual chronology, you might be able to use an old version of f-prot to remove the PKLite container.

The first versions of f-prot's heuristic virus removal software considered PKLite's method of jumping around to replace the PKLite code with the original code entry point to be a viral behaviour, and happily decompressed the binary and stripped off the PK container straight off. Sometimes it left crud on the end, but that didn't harm anything.

Needless to say, both FRISK and PK updated their code to not trample or trigger each other.

Rabidgremlin
I don't believe I packed the .EXE
ksaj
It is PKLite compressed. I looked already.

"PKLITE Copr. 1990-92 PKWARE Inc. All Rights Reserved" right there at the front. And I can see a lot of scrambled text that is exactly what one would expect to see from a PKLite compressed executable:

    OGRIDLOK regi
    Pstration prog
    J.Acker
    ma2(c) 1993:
    Select YES if y
    ou have a
    Pde, NO to exi
    InfoN
    CITh/CB
    imu$
    send3
    R10z:U
    oNo}dhoek&
    17985+
    Town.
    Lca?
    I will
    CODE
    <Ousing
    unlock-
    r leve
    @&e.2
... etc ...
Rabidgremlin
mmm, I don't remember doing that. But was uploading to BBS's at the time so may have done so. Also may have been trying to dissuade cracking :)
ksaj
You won't be patching it without decompressing it. Unless you run it under something that patches it in memory for every time it is executed. But that's a ridiculous amount of work.

See if F-Prot will decompress and remove the container, and then go from there. Make sure it's an early version of f-prot. It does look like an early PKLite, so you just might pull it off.

ksaj
Do you have any prepped GRIDLOK.REG files lying around?