This is a weird one

Would it be very difficult and/or possible to...
1
Take a file of any type ( exe, dat, bin, ect ) and cut it up in to pieces and then desguise it as a jpg or any other file but not just the file extension but any data contained within the file that would identify it as a jpg.
2
if you opened it as a jpg it would open like a jpg in photoshop or whatever. Thought the picture would be all garbled up because it's not accually a jpg.
3
Then be able to convert it back to it's original state.

Though I am not working on a project like this, the idea of it is itteresting to me.

Well, why would you want to take a .dat file and break it up into .jpg format?

Well, if the file is not a true .jpg or image format, opening it up in a photo editor would produce gargon or nothing, so point two is irrelavant :)

Regarding point three, this goes back to point one :). This seems like a lot of work if the only result is to return it back to its normal state anyway :).

Maybe this will interest you:
Steganography: Hidden Data (http://www.computerworld.com/securitytopics/security/story/0,10801,71726,00.html)

There are alot of processes that convert a file or files for the purpose of coverting them back. For example, file compression and/or encryption.
You are trying to read into what I am trying to accomplish, then the anwser the question. I don't mean for that to sound negative.

John, Thanks for that link! That is what I was trying to say.
I suppose what I need to do is figured out the structure of a jpg file or some similar file type I could manipulate. With that I suppose I just answer my question regarding difficulty.

Thank you both for you help. :)

I basically wanted to know the purpose you had, yes, there are many reasons for doing this. And encrypting and "de-cryption" go hand in hand :). We don't support malicious code here, and hacking was my initial concern, Especially when you start talking about MASKING an exe file as something else.........

Well, you will need to get the proper encoding to convert the file type into a JPG or BMP. I know in VB, you could attempt to use the SavePicture() method to convert your file type into a bmp file. In .Net there is probably a graphics class equivlent, I have not played with images enough in .Net to be sure.

Thank you for your response.
I understand your reasoning, and for the record, I dont write malicious code. Though malicious code would probably be the easiest program to write. usually I am at the receiving end of something that messes my computer up and I have to waste part of my life fixing it. It sucks.

Thanks again though..

p.s. The primary file I would be using is a rar file and/or selfextracting rar ( *.exe )