December 30th, 2013, 05:26 AM
[Reverse Engineering] Find data decryption algorithm.
First of all, Hi and Merry Christmas to everyone.
I am not sure if i've chosen the correct section to post my thread, so i apologize if its wrong and feel free to move it where you should.
now to the problem.
I am basically a 3D developer, i am writing importers and exporters of game files into 3d developing software (Blender for now), BUT lately i came across some files that meant to contain 3D data and they seem to be encrypted. I am not sure if i am using the correct word also but i assume that since in the hex editor the data does not contain characters in its total, its not encoded.
So what i am trying to do is to find my way in those unknown fields for me (both decrypting and reversing) and i am kind of completely lost :P
I started debugging the game trying to find where the file is accessed and to see how the data is handled, but it does not seem to be that easy.
From the few things that i know (btw i am using Olly to debug the game), i searched the memory for a byte sequence taken from the actual file (there are already tools available to unpack them from their archives) and i did found the place in memory where the file is stored. Then i thought that be adding a memory breakpoint in there the game would stop and i would see the data. That never happened...
So i have no idea what i should do now, i have no idea if my approach to the problem is correct.
Thats i am asking desperately for help :P If someone more experienced than me has some advice or thought or guidance to give please do so, i am asking for it.
PS: The decryption key that i am propably asking for should be a string??? could it be just and array of bytes?
Thanks in advance
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