Bitcoin was created more than a decade ago, and it did not initially have a built-in smart contract feature. A smart contract is an automated contract executed on the blockchain that executes, verifies, and enforces the terms of a contract without third-party intervention.

However, shortly after the birth of Bitcoin, people began to realise the potential of smart contracts and wanted to introduce their functionality to the Bitcoin network. However, implementing smart contracts on Bitcoin faces a number of challenges and limitations due to the fact that Bitcoin's design goals and security model are different from those of smart contract platforms such as Ether.

One of the most important limitations is the simplicity of Bitcoin's scripting language. Bitcoin uses a scripting language called Bitcoin Script to define validation conditions for transactions, but it is very limited in its ability to implement complex smart contract logic. This makes it difficult to write and execute complex smart contracts on Bitcoin.

In addition, Bitcoin's security and stability may pose some challenges for implementing a complete smart contract system. The design goal of Bitcoin is to be a decentralised digital currency that focuses on security and attack resistance. To achieve these goals, Bitcoin employs relatively conservative design choices that limit certain features and scalability. This conservative design has made the Bitcoin network more stable, but it has also limited its development in smart contracts.

Overall, Bitcoin has some historical legacy issues with smart contracts, mainly due to its design goals, scripting language limitations, and security and stability concerns. Nonetheless, there are still projects and solutions that attempt to extend smart contract functionality on the Bitcoin network, but due to the inherent functionality shortcomings of Bitcoin scripting, there have been no projects that have made a splash.

OP_CAT is coming back soon!

Today, however, there has been a resurgence in the expansion of Bitcoin's smart contracts. op_cat was initially part of Bitcoin's official command set, but due to the prudence of Satoshi Nakamoto, the opcode was moved out of the Bitcoin protocol in August 2010. op_cat allows for combinatorial concatenation of multiple byte strings of UTXO unlocking scripts, which can increase the programmability of BTC's mainnet, the scalability of its procedures, and the computational complexity of on-chain verification. scalability, and computational complexity of on-chain verification.

OP_CAT is already live on the Bitcoin Signet testnet on 1 May 2024

The reintroduction of OP_CAT provides Bitcoin with a powerful tool through which so-called smart contracts, which set pre-specified conditions for specific Bitcoin outputs, can be implemented. This not only provides a new approach to scaling, but also supports many other innovative approaches that rely on smart contracts. In addition, it signals that Bitcoin is more than just a payment network, but can also be a versatile and scalable computing platform.

The return of OP_CAT will bring major changes to Bitcoin:

It can enable and emulate restriction clauses (covenants), changing the dynamics of scripts and providing more useful features for the Bitcoin network. Similar to the 2021 Taproot upgrade, OP_CAT can create entirely new layers of functionality.

It enables and enhances higher level security features such as vaults and even a return feature that will return all assets to a "safe address" if a malicious actor obtains your seed key before the actor sends them away from you. Providing users with a higher level of protection against theft.

It is possible to create wallet permission lists and other dynamic limit output scripts, as well as a new form of wills/trusts for sending bitcoins to heirs.

It creates Layer2 and bridging mechanisms that connect other chains.

Relying on the return of OP_CAT, the basics are in place to run smart contracts on Bitcoin.

Bitroot: The Transformer of Bitcoin Smart Contracts

The conditions are now in place for Bitcoin to introduce smart contracts, and Bitroot is an enabler, a change agent, and the Bitroot project consists of three core components: the Bitroot Protocol, the BRVM, and the Bitroot Layer2, which work in tandem to give Bitcoin the ability to run a wide range of innovative applications.

Bitroot Protocol

The Bitroot Protocol is a native programmable asset issuance protocol based on Bitcoin.The various existing Bitcoin asset issuance protocols, which generally suffer from complex protocol implementations, poor user experience, and rubbish Unspent Transaction Outputs (UTXO) Ordinals are "engraved" on a particular Satoshi by embedding metadata into the transaction's Witness Data field that is "inscribed" on a particular satoshi. However, the Ordinals protocol has the undesirable consequence of the proliferation of UTXO.Runes homogenised token protocol based on UTXO has a more sensible technical architecture than Ordinals. It does not support NFT asset issuance, and the long font size of runes is not conducive to propagation and exchange listing.

Bitroot Protoco is a simple and flexible protocol that enables the minting and transfer of native assets on Bitcoin, and allows for the issuance of BRT20-compliant tokens and NFTs through the Bitroot protocol, which is positioned as a data layer on Bitcoin that can store arbitrary data in Bitcoin transactions (which can be deposited into the Bitcoin blockchain). Maintains a robust abstraction layer between the Bitcoin UTXO system and the Bitroot system. Provides more operability for asset innovation and applications on the Bitcoin chain.

But just issuing native assets on Bitcoin is not enough. Bitroot's vision is to enrich the BitcoinFI ecosystem by introducing smart contracts to Bitcoin, thereby leveraging Bitcoin's trillion-dollar liquidity. Therefore, Bitroot has developed and implemented BRVM, which makes Bitcoin interoperable with Bitroot Layer2, enabling two-way verification based on zero-knowledge proofs.

BRVM

BRVM is a concrete implementation of a computational paradigm expressing Turing-complete Bitcoin smart contracts, and can be thought of as a 'Bitcoin Virtual Machine'. Unlike the Ethernet Virtual Machine (EVM), BRVM does not perform operations on the chain, but rather verifies them, similar to the principle of Optimistic Rollups. Using this mechanism, any computable function can be verified on Bitcoin. As such, the BRVM is the infrastructure that connects BTC to the rest of Layer2.

The core principle of BRVM is to translate EVM/WASM/JavaScript opcodes into Bitcoin Script opcodes, which is a virtual machine that uses logic gate circuits as a kind of intermediate form between EVM opcodes and Bitcoin Script opcodes. With BRVM, instructions that would otherwise be processed on EVM/WASM can be processed directly on the Bitcoin chain.

The Bitroot protocol solves the problem of executing smart contracts on the Bitcoin blockchain through BRVM, but using a combination of logic gate circuits to directly express certain extremely complex transaction processing flow may generate a huge amount of work, which is a huge test for Bitcoin. Therefore, Bitroot will perform smart contract calculations in a Layer2 manner, and then verify the calculation results through BRVM, thus extending the computational power of Bitcoin smart contracts.

Bitroot Layer2

Bitroot Layer2 is a Layer 2 solution for Bitcoin that inherits the security of Bitcoin. In Bitroot, we build a layered virtual machine technology derived from the BRVM solution. This technology supports arbitrary types of computational operations through zero-knowledge proofs and optimistic execution mechanisms, and verifies the validity of Layer2 computations in the Bitcoin network. BRVM also enables us to support any front-end type of smart contract (e.g., smart contracts implemented in EVM).

The core significance of the birth of Bitroot Layer2 is to help BRVM solve the problem of needing a lot of computing power. Eco-users can perform all kinds of interactions in Layer2, such as DeFi, Metaverse, Chain Tour, DEX, and all kinds of derivatives transactions, and the computation of these applications will be done in Layer2, and then verified in the Bitcoin network via BRVM. This ensures the high performance required by the various products, and also ensures that the results of the transactions are validated by the Bitcoin network.

In a nutshell, Bitroot is not just an asset issuance protocol or Layer2, it's more of a turnkey solution for introducing smart contracts to the Bitcoin ecosystem. Starting from solving the problem of issuing Bitcoin native assets, to empowering Bitcoin native assets and introducing smart contract support, it was discovered that even if Bitcoin could run smart contracts, the weak performance of the Bitcoin network would not be able to support the large number of transactions.

Therefore, Bitroot lays the foundation for the entire Bitcoin smart contract scaling solution by deriving a high-performance Layer2 that supports bi-directional zero-knowledge proofs, and in the future, Bitroot is bound to pry trillions of dollars of liquidity on the Bitcoin chain through the introduction of smart contracts and become the vanguard of Bitcoin smart contracts.

A New Era for Bitcoin

Bitroot is driving a major change in the bitcoin ecosystem by introducing smart contracts to the bitcoin network. This will revolutionise the Bitcoin ecosystem, giving it a whole new look and a broader range of applications.

In summary, Bitroot's three core components each play a key role.

The Bitroot Protocol is an asset issuance protocol that allows for the issuance of BRT20-standard tokens and NFTs on Bitcoin, opening up new possibilities for crypto assets.

BRVM is a "Bitcoin Virtual Machine" that translates smart contract opcodes, such as ethereum virtual machines, into Bitcoin scripts to run and verify smart contracts on the Bitcoin chain.

Bitroot Layer2 is a high-performance Layer 2 network supporting bi-directional zero-knowledge proofs, capable of efficiently handling complex smart contract computations and obtaining validation on the Bitcoin network via BRVM.

Through the organic combination of these three links, Bitroot enables Bitcoin for the first time to have the ability to run a variety of DeFi, meta-universe, Chain Tour, DEX and other smart contract applications, expanding Bitcoin from a single digital currency to a multi-functional computing platform. This not only releases trillions of dollars of bitcoin's liquidity, but will also lead to a large number of innovative applications that will greatly enrich the bitcoin ecosystem. It can be said that Bitroot is opening a new era of smart contracts for Bitcoin.