Motivation

The crypto space suffers from a lack of compatibility between on-chain assets and off-chain applications. Web 2.0 games and applications offer a limitless utility potential for on-chain assets, but without a reliable and adaptable system to interconnect these two worlds, this potential remains untapped.

Moonsama has built a protocol that enables the bi-directional bridging of on-chain digital assets and off-chain applications, effectively eliminating the barriers between these two worlds.

Our mission is to enable the on-chain and off-chain worlds to work in perfect harmony, allowing the wide-spread adoption of applications that combine aspects of both.

This is achieved through the unique functionalities provided by Moonsama’s Multiverse Bridge.

The Multiverse Bridge

The Multiverse Bridge is a Web 3.0 tool capable of connecting on-chain assets with both on-chain and off-chain applications and metaverses. With it, it is possible to import on-chain assets into an app, i.e. an NFT becoming a unique character or skin in a game, and export game items into a blockchain i.e. an in-game currency becoming an ERC-20 when ported on-chain. The first implementation of the Multiverse Bridge is built on Moonriver, using a traditional EVM based web3 stack.

In this paper we present and discuss the components and functionality provided by the Multiverse Bridge. Moreover, we demonstrate its capabilities through our first use-case, the Moonsama Minecraft Metaverse integration. We hope we lay down the foundations for Metaverse connectivity with this protocol, and more integrations will soon follow suit.

It is easiest to present the Multiverse Bridge through its individual components, as depicted on Fig. 1. Unconventionally, we attempt to do so by traversing the stack from top to bottom.

Metaverse

A Metaverse is a novel concept that is best defined as a shared virtual environment that participants access via the internet. Metaverses are born out of the combination of different technologies, including aspects of social media, gaming, virtual reality and cryptocurrencies. None of these aspects can form a Metaverse by itself. Instead, it is the interaction between them that can form one.

Other recurrent features of Metaverses are the convergence of physical and virtual worlds, the existence of an internal economy and the ability to transfer digital assets between different spaces within the Metaverse.

Metaverses integrated with the Multiverse Bridge gain full compatibility with any connected chains. Digital assets on those chains can then play specific roles in that Metaverse’s associated applications and games. Via this described compatibility, an on-chain asset could become an avatar on a social media platform or a playable character in a game.

Oracles

Oracles are always necessary wherever the on-chain and off-chain world meets as trusted intermediaries. The Multiverse Bridge relies on oracles to insert an interpretation layer in-between the Metaverse and the on-chain protocol. Oracles can handle all the data and logic required to enable the cross-layer utility of the assets. Information such as a) the list of imported assets by a particular user, b) the effects of the assets in-game and c) behaviors such as what to do with an asset once it crosses the Multiverse Bridge, are all stored and pre-programmed by an oracle, e.g. a backend. Though centralized services, trusted middleman and single point of failures are generally frowned upon in the web3 world and their usage is best avoided, in case of e.g. a complex multi-player game which cannot run on the chain it is unavoidable. This is often the case for Metaverses, where e.g. a game server acts as the single source of truth aka. the trusted oracle. Nevertheless, should the Metaverse be on-chain or off-chain, the Multiverse Bridge protocol supports it.

The Multiverse Bridge is completely Metaverse agnostic. It is capable of connecting any Metaverse, provided the right oracle configuration. Said differently, any game/app will need its own customized implementation of an oracle to leverage the Multiverse. Interpretation of Multiverse Bridge events might differ depending on the Metaverse’s needs defined by its unique characteristics and mechanics, therefore it’s hard to generalize it with a single protocol. The Multiverse Bridge standardizes a Metaverse oracle’s relationship with the on-chain world, without imposing strong opinions or limitations on it.

Supported On-Chain Assets

Supported on-chain assets The Multiverse Bridge currently supports the 4 fundamental asset standardsi:

• The native token of the EVM chain
• The classic fungible token standard ERC20
• The non-fungible token standard ERC721
• The semi-fungible token standard ERC1155

Upon the appearance of new standards the protocol can be extended.

Contracts

The core of the protocol are the contracts, and in principle they work similarly to any blockchain bridge. Their main purposes are 1) to serve as a standardized registry of on-chain Metaverse domains and related oracles 2) to standardize binding on-chain assets to said domains 3) to provide a standardized interface for oracles to manage assets belonging to their domain and to register related events.

The protocol takes away the pain of having to implement all of these from scratch each time someone wants to meld a Metaverse with on-chain assets. It is a generic platform for everyone to build a Metaverse integration on.

When importing assets into a Metaverse or manifesting off-chain items through the bridge, the outcome is enforced by a ruling oracle of the domain. Such outcome will depend on factors such as the type of asset being bridged or the direction of the bridging. Bridge operations are executed by a whitelisted account belonging to an oracle, or by anyone sending a correct payload with an oracle’s signature on it. We identified 4+2 basic operations that are needed to support a Metaverse: import, irreversible import, export, summon, change owner and change beneficiary.

Chain-to-Metaverse Bridging (C2M)

Simple Import: allows on-chain assets to be imported into an off-chain metaverse. Once bridged, the on-chain asset is stored in escrow.

Irreversible Import or “Enrapture”: allows the import of on-chain assets meant to be bridged just once. The asset will be burnt, “baked into the metaverse” as part of the import, and will get locked permanently in the Otherside contract which acts as a publicly verifiable asset graveyard without any owners or functions to get anything out.

The bridge logs the actions, allowing the Oracles to trigger the metaverse specific interpretation of them, e.g. to equip the user’s character with a skin or open a loot box.

Metaverse-to-Chain Bridging (M2C)

Simple Export: allows the export of an escrowed asset (as a result of a previous Simple Import), back to the blockchain layer. The asset returns to its owner’s wallet.

Summoning Export: allows the export of native metaverse items into the blockchain layer, becoming on-chain tokens. These tokens are minted as part of the export. For this we developed a special ERC1155-ERC20 hybrid contract. Read more about it in the Token Factory section.

Skin in the game

The term “bridging” is slightly different in this context from the conventional meaning of bridging. Bridging in the Multiverse bridge is closer to the act of staking, or bonding. The Moonsama Council, the governance of Moonsama holders, can make Metaverse specific rules e.g. to confiscate NFTs in case the bridged player was caught cheating. This is essential, however, to ensure that the economy of the Metaverse is not tilt. Since resoures earned in-game bear significant value, cheaters potentially could wreck the economy if the system can be exploited. A user must have skin in the game. Bridging to a Metaverse always makes the user subject to the rules of the Metaverse, akin to entering a country makes one subject to the country’s rules. It is important to get familiar with these rules before deciding to “enter” a Metaverse to decide whether the risk is worth it and to avoid unpleasant surprises.

In Multiverse Bridge V2, the current import/export/enrapture terminology is updated.

Change Owner and Beneficiary

The remaining 2 operations, change owner and change beneficiary, do not need much further explanation. When an asset is imported into the Metaverse it is associated with a particular owner and beneficiary in the on-chain entry. The interpretation of this, again, left to the Metaverse. It allows for features such as in-game trading, or borrowing markets. These topics will be subject of further exploration.

Bridging summary

To sum up, the existence of the Multiverse Bridge guarantees a full compatibility between on-chain assets and off-chain games and applications. Moreover, the Multiverse Bridge is game/app agnostic. We envision the Multiverse Bridge becoming the go-to solution for any project or team of developers aiming to connect their games and applications with assets on Moonriver, and in the future, a larger suite of chains.

Token Factory

Token Factory is the contract used for Summon Exports from a metaverse. It is an ERC-1155 that spawns its individual ID tokens as standalone ERC-20s instead of internal accounting, acting as their parent. Transactions made on the individual ERC-20s trigger and log appropriate events in the parent contract and vice-versa. These tokens combine the advantages of the fungible/non-fungible worlds. This means exported assets are both NFTs (therefore supported by NFT marketplaces) and regular ERC-20 tokens (supported by DEXs, CEXs, etc.), depending on which contract we manage them from. The only disadvantages are: slightly higher gas cost, allowances have to be made on the parent/children separately, and introducing the decimal concept to ERC-1155 because it has to match with the underlying ERC-20’s.

All the summoned (minted) tokens are made by the factory from all the integrated Metaverses. We believe we made a quite generic standard that caters for all fungible and non-fungible needs. A Metaverse can only mint an ERC20, or looked at from the parent, an ERC1155 with a specific ID it was permissioned for. Obviously, the oracles of the Willy Wonka Metaverse should not have access to the minting of Minecraft Gold Tokens and vice-versa.

In Multiverse Bridge V2, the decimal points are settable per new child token deployment, and the bridge is capable of minting any kind of token, not only tokens from the Asset Factory.

Trust Layer

The V1 implementation is anchored into the Moonriver network as the trust layer, which is the EVM parachain of Kusama. Our technology is compatible with any other EVM chain as well, so it is designed to be a multi-chain protocol. We are also exploring possibilities to build a custom parachain for Metaverse connectivity which would bring benefits in scalability, interoperability, trust, and on-chain governance.

Multi-chain support

Not being limited to a single chain is imperative to build a limitless ecosystem. The Multiverse should not be accessible only from a single chain. Communities from other chains would be completely locked out otherwise, and the protocol could not be able to benefit from cool innovations or growth elsewhere.

The good thing is that the Multiverse Bridge was designed with this kept in mind. Instances of the Multiverse Bridge can be deployed on other chains within minutes and get connected to the Metaverse Oracle, or with the addition of multiple Oracle instances.

Example: You have an Exosama girl NFT on the Ethereum mainnet and a cool flaming sword NFT on Moonriver. By bridging both items on the bridge portal from the respective wallets, Exosama on the mainnet instance of the bridge, sword on Moonriver into the same Metaverse domain, you can equip the the flaming sword to your Exosama. It is entirely up to the Metaverse implementation what the on-chain items turn into inside their world, irregardless which chain the assets live on.

Conclusion

The current implementation is the first version of the protocol. It was developed tightly along with the first integration, the Moonsama Minecraft Metaverse presented in an upcoming section. As we experiment with Metaverses and conduct new integrations, the protocol is going to be extended with new features.

Metaverses are a blooming industry. Their cross-sectorial nature makes them capable of creating value in a lot of different tables, and the crypto space is no exception. However, the lack of compatibility between on-chain assets and Web 2.0 games and applications (which Metaverses heavily rely on) form a solid obstacle that threaten to slow down the widespread presence of on-chain components in Metaverses.

The Multiverse Bridge provides a working solution to this specific problem, allowing the interconnectivity between on-chain assets and off-chain Metaverse elements. Moreover, its value proposition is now validated by its functional implementation in Moonsama’s Minecraft Metaverse.

The Multiverse Bridge is chain and Metaverse agnostic. Provided a correct implementation coupled with a customized oracle, the Multiverse Bridge is able to connect any on-chain asset with any Metaverse element. We envision the Multiverse Bridge becoming the go-to solution for bridging countless Metaverses with the crypto space, allowing both sides to optimize their value creation thanks to the other.

Metaverse Integrations

On September 21st 2021, Moonsama released a collection of ERC-721 NFTs, codenamed MoonsamaV1. The collection, formed by 1000 unique NFTs, was made available on https://marketplace.moonsama.com/. With this, MoonsamaV1 and moonsama.com became the first collection of NFTs and the first NFT marketplace to ever be launched on Moonriver.

The launch of MoonsamaV1 was coupled with the announcement of a roadmap that aimed to create additional utility for the NFTs by making them compatible with a Play-To-Earn off-chain suite of games and apps.

On October 31st, 2021 Moonsama launched Moonsama’s Minecraft Metaverse, the first game with full compatibility with digital assets on Moonriver.

Big Pic

For the Metaverse integration with the bridge, a custom oracle was developed that sits between the Minecraft servers and the bridge. Players communicate with the Oracle and the Multiverse Bridge contracts through a custom UI, the Moonsama Minecraft Metaverse Access Portal.

Bridgable Assets

Moonsama’s Minecraft Metaverse leverages the Multiverse Bridge to allow the import and export of Moonsama NFTs and in-game items

These are the assets that can currently be bridged to and/or from the Minecraft Metaverse:

MoonsamaV1 NFT

•NFT Type: ERC-721

•Features:

•Unlock access to Moonsama MC servers

•Become a playable character in-game

•Boost character stats

•Makes holder eligible for a piece of the global “gganbu” share of Carnage events

??? (mystery collection)

•NFT Type: ERC-1155

•Features:

•VIP ticket to unlock access to Moonsama MC servers

•Items that become item skins in-game

•Off-hand items

Minecraft resources

•NFT Type: hybrid-ERC-20 / ERC-1155

•Features:

•Used to craft on-chain items via the on-chain crafting tree

•Used in the traditional Minecraft system

•Exportable via Summoning Export

•Currently limited to wood blocks, cobblestone blocks, iron blocks, iron ingots, and gold ingots; expansion planned

On-chain crafted items

•NFT Type: ERC-1155

•Features:

•Craftable via the upcoming on-chain crafting tree

•Unlock in-game benefits

•To be announced soon

•Designed to reward recurrent players by boosting their in-game effectiveness substantially

Moonsama Embassy

•NFT Type: ERC-1155

•Features:

•Non-tradeable, non-transferrable NFTs that can only be bridged

•Grants Moonsama friend communities access to the Moonsama Metaverses

Seasonal Plots

•NFT Type: ERC-721

•Features:

•Tokenized plot tokens grant ownership of virtual land when bridged

•Can be bought from earned resources

•Seasonal; plots are snapshotted and tokenised with game-plot-data at season’s end

Multiverse Art

•NFT Type: ERC-1155

•Features:

•Created by renowned NFT artists in the Dotsama ecosystem

•Unique wearable user skins in-game

Oracles

The oracle associated with Moonsama's Minecraft Metaverse enforces different outcomes depending on the type of asset.

• Importing an ERC-721 MoonsamaV1 NFT will store it in an escrow contract, unleashing its associated in-game effects while it remains there. Exporting it from the game will release the NFT from the escrow and return it to the owner’s wallet, also interrupting the in-game effects.
• Importing or irreversibly importing the ERC-1155 ??? (VIP Ticket) NFT will either escrow the ticket, giving the player access to the server and a special skin, or trigger its burning, locking the asset in the Otherside contract and permanently unlocking the corresponding in-game benefits and rewards for the associated Microsoft account. If burnt, the VIP Ticket NFT can’t be exported back to Moonriver.
• Importing or Irreversibly importing an ERC-1155 On-chain Crafted Item NFT will unleash its associated in-game effects.
• Exporting an ERC-20-1155 Minecraft resource will trigger its Summoning Export. The resources are deleted from the user’s in-game inventory and minted as on-chain tokens through the Factory.

Moonsama Minecraft Metaverse Access Portal

Players can manage their Minecraft profile and import/export assets between the chain and the metaverse through a single-page application off-game.