Will Duping Exist in Diablo 3? We asked an Expert.
Posted 28 September 2011 by Azzure

The golden question – will dupes plague our beloved Diablo game ever again or is it a thing of the past? Forum reader and DB expert Grayson Carlyle has been kind enough to answer a few questions about Duping and a Diablo game handles item’s. It is an extremely interesting read, do not miss out! Click More to check it out.

Is duping a thing of the past? Have changes in technology abolished the whole concept of duping? Could you please explain how technology has evolved regarding this subject, such as the way databases store data (ie items).

It’s actually not a technological change, but rather a perception of how various objects within the game system are viewed.

Previously, it seemed very logical to say that a character could equip a bunch of items, carry a bunch of items and that they were the owner of these items. So a weapon slot on a character sheet would then be filled via the idea that “This item slot contains this item” and all the data associated with that item was stored along with it. This was conceptually easy and aided by the fact that it was simple to create a random item using what we call a seed value; use the same seed value in an item generation algorithm along with the item type and you’d get the same item each time. It was very efficient way of storing an item; your weapon or armor slot just carried that seed value along with it.

So the next step that comes up, after designing your character and item storage is “How do we pass these items to other characters?” or in the case of Diablo, to be able to drop it on the ground. The solution, from this frame of reference, is obviously to pass that seed value and item type along and store it with the piece of terrain, or the receiving character. That’s essentially a cut and paste job. But what if you can, instead of making it cut and paste, make it copy and paste? Or paste it multiple times? All players had to do was interrupt that cut and paste process in some manner that would leave your copy of the item untouched, or leave a copy “in the buffer” and keep pasting it. Because of the inherent nature of cut and paste and the fact that Diablo is all about items, be it getting them, trading them or upgrading them (there were dupes based on socketing an item in Act V in D2), there are a whole lot of possible places to look for a weakness in that action. And players found a lot.

It took a different view of characters and items for the duping problem to be solved, and in truth, solved rather trivially. It had been solved before Diablo II, but for whatever reason, they decided not to develop the game that way.

Instead of an item being something that was in your helm slot, why not have an item that we can put in your helm slot? Keep items entirely separate, store them by themselves as separate objects. If you approach a game from a client-server perspective, this ends up being very obvious. But that’s just not how people designed most games back then; it was a first person shooter concept, not a real-time strategy or RPG concept.

So if we have all our items stored together in one place, regardless of how many characters there are, then those items are only moved between characters, the ground, trade windows, etc… They aren’t a part of your character, they’re just being lent to your character for now. This entirely removes the cut and paste operation; each item can only be in one place at a time. It was on the ground, you click on it, and now it’s in your inventory. There’s nothing that says your inventory contains that item, instead, you have to go ask the item where it is. When you load up a character, you look for all items that say they’re currently attached to your character ID, instead of fetching the items that your character says it has. There’s no cut, there’s no paste. So items simply can’t be duplicated when you store them this way. Because of this, it’s possible to control exactly how and when an item can be created or deleted. When an item does get deleted, it doesn’t remove that item from your character, the item itself is deleted. Your character can’t own something that doesn’t exist anymore!

That doesn’t remove all types of hacking though. If something like the chest hack from D2 were found, then you could trick the server into creating items it shouldn’t be, giving you an unlimited supply of “legitimate” items. But duping itself is eliminated because of the fundamental nature of how they are stored.