Research: C-Gear Skins

[Hi-Techneon]

C-Gear Skins
You probably know that the C-Gear has various skins. There's a Chillarmy skin, a Munna skin, a Pikachu skin, a Purrloin skin, an Audino skin, a Blastoise skin, etc.
The current C-Gear skin is stored in the game's save file. This means that, through save file hacking, we can export and import custom skins to the save and use them. However, there's one problem. Of course, these skins aren't saved as a simple BMP, or a PNG, or a JPG. No, they're encrypted. If we could crack the encryption, we should be able to import and export our very own C-Gear skins and make the C-Gear even more personal.
Skins are 256x192 pixels and have 16 colors.

So let's all try to crack it and make the C-Gear more awesome than it already is!

 

[Darthatron]

Are you sure it's not just compressed with one of the DS compression functions?

 

[Hi-Techneon]

Are you sure it's not just compressed with one of the DS compression functions?

To be honest, no. Could you maybe show me all compression functions and allow me to try cracking it with those?

 

[Full Metal]

:offtopic
Wouldn't this go in the R&D section?
{ on topic }
Maybe GF got smart with us and started using a special type of encryption that uses a function in the games code to decrypt? ( just a thought )

 

[Hi-Techneon]

:offtopic
Wouldn't this go in the R&D section?
{ on topic }
Maybe GF got smart with us and started using a special type of encryption that uses a function in the games code to decrypt? ( just a thought )

First of all, this is the R&D section :)
Well, I don't think they can encrypt a picture in the save file that easily, and most encryptions increase in size, while this encryption decreases in size.

 

[Full Metal]

Oh.

Hm...
Well, first off, Sorry. :|
I just woke up when I posted this. I thought it was in the toolbox... :(:
ANYWAYS...yea, you make a pretty good point...
except, why is the skin in the save file and not just a reference to the skin?
I mean...that just seems stupid and inefficient.
IDK, maybe that's just the C-programmer in me speaking...
I think if we can figure that out we might be able to figure out a little more about this.
... maybe. :)

 

[Hi-Techneon]

I don't think it'd be built into the game, or else new skins couldn't be made.

Yeah, that's why. How could they else put a Purrloin skin in Japan for download if another participant could have won with another design?

 

[pokewalker]

Hmm.... I think, that when you acces GBL, new information is sent to the game overwriting the old skin. The old skin is then not in it anymore, but on the GBL, where all of them are available.

 

[Darthatron]

It's not unheard of. Square Enix use a variation of LZSS compression in FFTA, and it's all decompressed with a routine in the game.

Why couldn't they use it? I don't understand your logic. They just send out a compressed image and decompress it when it's downloaded/saved/loaded/whatever.

 

[Kaphotics]

Posting to let you all know about PokeStock's subprogram that allows you to edit the C-Gear skin of your save file.

C-Gear skins are saved into the save file, with encryption as you already know. PokeCGear exports these (probably encrypted) skins in a format ".psk". Poke Skin or whatever. C-Gear skins are 256x192 pixels and can also be exported to bmp format.

Over at Project Pokemon you can find this PokeStock and the translated version, in addition to the C-Gear Skin Exchange Thread where you can download past skins or upload new ones.

C-Gear Skin Exchange Thread
PokeStock Main Download Thread
Kaarosu's Translations of the Subprograms Thread

Hope this information helps in whatever you are trying to do :)

 

[Hi-Techneon]

Posting to let you all know about PokeStock's subprogram that allows you to edit the C-Gear skin of your save file.

C-Gear skins are saved into the save file, with encryption as you already know. PokeCGear exports these (probably encrypted) skins in a format ".psk". Poke Skin or whatever. C-Gear skins are 256x192 pixels and can also be exported to bmp format.

Over at Project Pokemon you can find this PokeStock and the translated version, in addition to the C-Gear Skin Exchange Thread where you can download past skins or upload new ones.

C-Gear Skin Exchange Thread
PokeStock Main Download Thread
Kaarosu's Translations of the Subprograms Thread

Hope this information helps in whatever you are trying to do :)

This is useful, thanks alot. If we could find the way how it exports the PSK as a BMP, we could reverse it, exporting BMPs as PSKs and adding custom C-Gear Skins. I'll look into it :)