Adding atomic swaps into World of Warcraft

[Ferib]

I was looking into multiple ways to perform some sort of atomic swaps between my in-game World of Warcraft items and my bitcoins.

I was already familiar with HTLC transactions and so was looking for in-game mechanisms that allowed me to expose a secret AFTER a in-game trade is completed, but at the same time the receiver (Bob) must be able to verify that the sender (Alice) is in fact giving him his secret item. This would allow Bob to trade various in-game items agains Alice's her special Bitcoin item, as Bob will be able to claim the secret s from the item, to redeem the HTLC

my full write-up can be found here https://ferib.dev/blog/bitcoin-atomic-swaps-in-World-of-Warcraft

TL;DR an orcale (Charlie) is needed to PGP sign a message as Bob nor Alice is able to verify the "minted" in-game item contains the actual secret before/after trading it.



The actual implementation for such AddOn isn't mentioned in the blog, but the idea is that Charlie signs messages that both Bob and Alice trust. This allows Alice to inform Bob which item (itemId+creator) holds what Bitcoin value, txid, receiver, etc. So Bob can use Alice's note, verify Charlie's signature, and trust Charlie this is correct.

[flapduck]

What you're describing here is not atomic.

You've reintroduced a trusted third party. "Charlie signs a note that itemId+creator maps to H/txid" is just escrow by reputation. The game client gives you no verifiable link between the traded object and a Bitcoin preimage before the trade. Blizzard can roll back trades, duplicate items, or ban accounts. An addon can't provide a binding commitment. PGP proves Charlie spoke. It does not prove the item will reveal the preimage, or that the specific item traded is the one Charlie described.

True atomicity would require the game to emit a signed, publicly verifiable receipt for the exact trade (or a TEE attestation) that can be used as a Bitcoin adaptor signature or HTLC trigger.

[Ferib]

What you're describing here is not atomic.

You've reintroduced a trusted third party. "Charlie signs a note that itemId+creator maps to H/txid" is just escrow by reputation. The game client gives you no verifiable link between the traded object and a Bitcoin preimage before the trade. Blizzard can roll back trades, duplicate items, or ban accounts. An addon can't provide a binding commitment. PGP proves Charlie spoke. It does not prove the item will reveal the preimage, or that the specific item traded is the one Charlie described.

True atomicity would require the game to emit a signed, publicly verifiable receipt for the exact trade (or a TEE attestation) that can be used as a Bitcoin adaptor signature or HTLC trigger.

It is indeed not a pure atomic implementation as it is indeed very challenging due to a lack of cryptographic primitives.

There is indeed trust required on the initial setup as I failed to figure out a way for Bob to verify by himself that he is trading against the correct item, which imo is only possible if the game server would embed a pre-image visible during trade, and a secret only visible to the item holder.

Therefore the best option was for Charlie to "mint" the item and create a PGP signature as proof, which indeed requires trust.

So I'm left with one last question on how to make the setup work without Charlie :3

[markm]

Likely trying to bind bitcoin directly is just not workable.

Better to simply come up with a number of the game's own currency that to you at a given moment seems worth the amount of bitcoin you want, such as by seeing the buy-offers in bitcoin on a Wow-money versus bitcoin marketplace and feeling confident that if the trade happens right now the amount of WoW money obtained for the item will still be worth about the amount of bitcoin you were looking for.

In the old days WoW money was not "allowed" to be traded though, back then various "gaming/gambling laws" and such made most games have to say in their terms and conditions that players are not allowed to go trade the money or items on third party game-asset-market sites.

So back then there were reasons for games to not make it easy or secure to do such things.


-MarkM-

[Ferib]

seeing the buy-offers in bitcoin on a Wow-money versus bitcoin marketplace

I am not sure if im following correctly but this article is a result of my best effort to create something that can act as a Wow-money versus Bitcoin marketplace.

Due to the need of Charlie it is indeed impractical to mint and exchange these "Bitcoin items" on the daily, but it allows for some sort of bridging.

[markm]

I am not aware whether or not WoW-money and WoW-items/characters/accounts buying and selling is nowadays still against the game's terms, but...

This kind of application seems to be a case where trust is going to be "of the essence" until/unless the WoW platform itself decides to support it directly.

Basically either someday they will make their own coin or token or will launch NFT items and/or accounts or both, or they will not.

To me it has for "yonks" (arbitrary unit of time) seemed that one of the usefulness of games is as a trust-building and trust-testing and trust-confirming environment.

I have met some players who insist that because something is a game it is perfectly acceptable for them to screw you any way they can, but I have also seen, a lot over many decades, that one can build strong trust-relationships too.

So to me it is maybe a good thing that trust is needed to trade WoW money and/or items outside of the game.

Are there not still trusted / trustable game-stuff-trading venues that cater to World of Warcraft?

You could also look into rapid tit-for-tat small-scale trading script/app development, maybe, especially using the Lightning network, it could suffice to trade fractions of a satoshi worth of WoW money at a time rapidly until one side or the other reneges, the tiny scale involved making a renege just a little piece of the "fees" as it were?


-MarkM-

[Ferib]

Yeah as pointed out in the article there are indeed markets that are selling goods/services for gold or sometimes even "real money", and the problem with these services is that a third-party is collecting the goods to then finalize the trade.

For example, Charlie takes gold from Alice, and wait for Bob to complete a dungeon with Alice to make sure she gets her item. So Charlie then trades the gold with Bob after Bob shows proof to Charlie that Alice got her item.

There are alternatives to this, from special mount items and what not. Which is again, a third-party holding onto all the items at once.

In my proposal, there is still need for a third-party but only during the setup of the trade. Once Alice obtains her in-game item after locking up funds in a HTLC, she can trade it with Bob after passing a PGP note so Bob knows what he is trading against.

This setup I found to be the best solution as indeed the game devs aren't adopting to NFT's or other types of tokenization. This is still a low interaction (using mailbox to send items) and low labour (only need to 'mint' the item, not verify proof from Bob on a Discord server guessing if the screenshots provided are manipulated or not).

I hope games never embed NFT's or any currency into their game as they will turn into "for profit" games, which means "labour". And once a 'game' becomes 'work' there is no fun or joy in actually playing the game. We all seen Axie Infinity, Crypto Kitties and well, NFT's in general. MMO's like Wow (and even OSRS) are actually fun to play, and they only have "value" as other players can often help you out a lot by co-operating in the game.

Anyway, this isn't some multi trillion dollar market, it just be fun to have a censorship resistant way of adding value into ones inventory, without it depending on the games economy.