Author: Chester, Research Lead of UTXO Stack

RGB++ Layer is a concept upgraded from RGB++ Protocol, representing a higher level of abstraction that extends isomorphic binding, smart contract capabilities, and bridgeless cross-chain functionality to all UTXO chains. With RGB++ Layer, the Bitcoin ecosystem will surely be further enriched. In particular, driven by RGB++ Layer, the rise of Bitcoin Finance (BTCFi) will lead the Bitcoin ecosystem into a new era of prosperity.

RGB++ Layer has multiple functions and brings many excellent features to the Bitcoin ecosystem. Its importance can be explained from the following three aspects:

  • RGB++ Layer is the asset issuance layer of Bitcoin.

  • RGB++ Layer is the smart contract layer of Bitcoin.

  • The RGB++ Layer is the interoperability layer for the entire UTXO world.

Bitcoin’s asset issuance layer

The current asset issuance protocols on the Bitcoin chain, such as Ordinals or BRC20, are far from a perfect design and rely heavily on centralized indexers. Unlike any previous solution, RGB++ Layer can serve as a powerful asset issuance layer for Bitcoin.

RGB++ Layer supports the issuance of various RGB++ assets, including user-defined tokens (UDT) similar to ERC20 and digital objects (DOB) similar to ERC721. Unlike Ethereum, ERC20 and ERC721 are issued and stored by smart contract accounts, while UDT and DOB are stored in Turing-complete UTXO, which means that they are first-class assets on RGB++ Layer, and their status is equivalent to Ether (ETH) on Ethereum.

Thanks to the advantages of the UTXO model, RGB++ Layer can create a new paradigm for asset issuance - allowing the same asset to be issued on multiple chains at the same time, with different proportions on each chain. This will provide asset issuers with a high degree of flexibility. When project teams issue tokens, they don't have to worry about losing users on other chains due to issuing on one chain. Instead, they can issue part on BTC, part on BCH, and even part on the Dogecoin chain, thereby extending their influence to the communities of all UTXO chains.

In addition, RGB++ Layer will introduce a new asset issuance model called IBO (Initial Bitcoin Offering). This can be understood as the Launchpad for all RGB++ assets. The IBO platform supports the creation of a capital pool directly on UTXOSwap (a UTXO-based decentralized exchange), enabling newly issued assets to be traded with high liquidity. The IBO issuance method strikes a balance between the venture capital (VC) model and the fair launch (Fair Launch) model, providing a more sustainable approach. It avoids the problem of lack of interest in the community while also ensuring that the project team remains motivated.

Bitcoin’s Smart Contract Layer

RGB++ Layer uses CKB's smart contract stack to provide Turing-complete programmability for Bitcoin. With smart contracts, the Bitcoin ecosystem can build various DeFi protocols and create a unique panorama of Bitcoin Finance (BTCFi).

For example, UTXOSwap, as a decentralized exchange (DEX) protocol, is the central hub of the RGB++ Layer, bringing together the liquidity of various UTXO chains. UTXOSwap adopts intent-based transactions as its core, implements the process of off-chain matching and on-chain verification, and uses the parallelism of UTXO to improve transaction efficiency.

If you think UTXOSwap is just Uniswap for the Bitcoin ecosystem, you are wrong. In addition to the basic swap, it also supports limit orders and TWAP (time-weighted average price) transactions because it is intention-based. For example, users can actively express their trading intentions, such as "exchange 10 A tokens for at least 20 B tokens", instead of passively accepting the market price.

Another example is Stable++, a decentralized over-collateralized stablecoin protocol. It will issue the first stablecoin USDPP on the RGB++ Layer. Stable++ leverages the powerful Turing-complete programmability of the RGB++ Layer to efficiently build an over-collateralized vault and liquidation module. As a user, you can pledge BTC or CKB to mint USDPP. USDPP is a stablecoin compatible with all UTXO chains, and it can circulate freely within the Bitcoin ecosystem.

In general, the atomicity of the UTXO model enables UTXO to operate like Lego, allowing assets from different chains to interact and combine with each other, thereby stimulating more DeFi innovations. This will promote the development of BTCFi and benefit the entire Bitcoin ecosystem.

Interoperability layer for the UTXO world

As an inclusive layer, RGB++ Layer can connect all UTXO chains and create a universal interoperability layer for the entire UTXO world. This allows various assets from UTXO chains such as Cardano, Dogecoin, BSV, and BCH to be seamlessly integrated into the Bitcoin ecosystem, breaking down asset silos.

The unparalleled feature of the RGB++ Layer is the bridgeless cross-chain (Leap). This mechanism allows assets on the UTXO chain to cross to another UTXO chain without a cross-chain bridge. For example, if Alice wants to transfer her RGB++ assets from the Bitcoin chain to the Litecoin chain, she first needs to spend the Bitcoin UTXO bound to her RGB++ assets. Then, a transaction is constructed on the RGB++ Layer to change the unlocking conditions of the Turing-complete UTXO to her Litecoin UTXO. In this way, the transfer of the asset from the Bitcoin chain to the Litecoin chain is successful.

With this feature, technically speaking, all RGB++ assets can be considered universal assets in the entire UTXO world, as there are no longer barriers between chains and assets can move freely.

Imagine: you can use A tokens issued on the BTC chain to exchange for B tokens on the Cardano chain through a decentralized exchange. You can use Meme coins on the Dogecoin chain to play GameFi on the Bitcoin L2 DApp chain. You can use DOB on the CKB chain to subscribe to services on Nostr, and so on. This brings the interoperability of RGB++ assets within the UTXO world to an unprecedented level.

Looking ahead

Looking forward to the future, due to the existence of RGB++ Layer, the Bitcoin ecosystem will be connected into an organic whole. Various UTXO-based assets, including inscriptions and runes, will flow seamlessly on the RGB++ Layer, significantly enhancing the liquidity of the Bitcoin ecosystem. BTCFi protocol innovations based on the UTXO model, such as decentralized trading, lending, and mining, will continue to emerge. Ultimately, BTCFi will thrive, leading the Bitcoin ecosystem into a prosperous new era.