You mean just like all the MMORPGs on the market today?
Im sorry to inform you but there are home made freeservers for alot (almost all of them that are popoular and has been around for more than 2 years) of the MMORPGS out there today. In some cases the server software is "stolen" from the game company that sells the game service and in some other instances a bunch of people get together and rewrite the whole servercode from scratch.
If you actually mean that every piece of the information would be on the servers only and never sent to the client i would have to ask how the player would actually play the game at all. I you can see it, its in your computers memory and you can copy it to the disk or whatever. Its actually not uncrackable at all.