[2.0] Decrypting a File (d2s)

Hello everyone. I have been trying very hard lately to decrypt Diablo II Single-Player character files (so I can make an editor).

I was wondering, how can I go about doing this?

This is not illegal because if it was Blizzard would try harder to protect the single-player character files and open bnet from hacks if this were the case, so I was wondering if anyone knew how to do this. ALSO, this is for OPEN BNET, I am in no way doing this to affect closed bnet servers.

Like I mentioned above, I am trying to make an open bnet character editor/item maker since everyone out there is a little outdated now.

Thanks in advance.