The BTC ecosystem is advancing rapidly in technology, with various expansion solutions emerging continuously.

Since the first quarter of 2024, the technological advancements in the BTC ecosystem have been rapid, especially in programmable expansion solutions. This article will introduce several noteworthy BTC expansion solutions, including Fractal Bitcoin, AVM, OP_NET, BRC100, and programmable runes.

Fractal

Fractal is a scalable framework virtualized based on the Bitcoin Core client software. It recursively creates a tree structure, where each layer of the blockchain can enhance the performance of the entire network. Fractal is fully compatible with Bitcoin and its infrastructure, but activates the op_cat operator, allowing for more logic to be implemented.

Fractal is developed by the Unisat team and is expected to launch its mainnet in September 2024. In its tokenomics, 50% is generated from mining, 15% is allocated for the ecosystem, 5% is pre-sold to early investors, 20% is distributed to advisors and core contributors, and 10% is used for building partnerships and liquidity.

In terms of architecture design, Fractal encapsulates the bitcoin core client into a deployable and runnable blockchain software package (BCSP), by recursively anchoring multiple BCSP instances running on the Bitcoin mainnet. It also makes some modifications to the bitcoin core, such as shortening the block confirmation time and increasing the block size to enhance performance.

Fractal introduces a joint mining mechanism, where one out of every three blocks is generated through merged mining with BTC miners to enhance network security. In addition, the newly created virtualized instance chain will have a protection period during the startup phase until the instance reaches a secure and healthy state.

AVM

AVM(Atomicals Virtual Machine) is the BTC smart contract implementation of the Atomicals Protocol. It creates a virtual machine that simulates BTC scripts and opens up multiple raw BTC opcodes, allowing developers to implement smart contracts through combinations of Bitcoin scripts.

AVM achieves Turing completeness through a dual-stack PDA, operating in a sandbox that includes an indexer, instruction parser, and global state. Its instruction set contains the complete BTC opcodes, allowing developers to program using the functionalities of BTC that are not enabled.

As an architecture, AVM is applicable to almost any metadata protocol, requiring only minor adjustments to the indexer under the virtual machine. Currently, the AVM has released a test version, and the relevant code has been open-sourced.

OP_NET

OP_NET aims to introduce Ethereum-like smart contract functionality to the Bitcoin network, but in a way that is more aligned with the characteristics and architecture of Bitcoin. It provides a complete, compact, and user-friendly development library, primarily written in AssemblyScript.

OP_NET retains the block consensus and data availability of Bitcoin by executing complex computations on Bitcoin blocks through the virtual machine (OP_VM). It supports multiple programming languages and utilizes Tapscript to enable advanced smart contract capabilities.

In the OP_NET network, users need to pay an additional fee, and the transaction packaging order will be sorted based on the fee. To expand the use of BTC in DeFi applications, OP_NET provides a Proof of Authority system, allowing BTC to be wrapped as WBTC.

The OP_NET ecosystem covers multiple areas including decentralized trading, lending, market making, liquidity provision, and cross-chain bridges, featuring various projects such as Motoswap, Stash, and Ordinal Novus.

BRC100

BRC-100 is a decentralized computing protocol built on the Ordinals theory. It achieves complex DeFi operations by adding new actions such as "burn" and "mint" to brc20. Developers can expand more operators based on the BRC-100 protocol.

BRC-100 provides operations such as mint2/mint3 and burn2/burn3, allowing tokens to be converted between the UTXO model and state machine model. It supports cross-chain operations and has extension protocols like BRC-101, BRC-102, and BRC-104.

The BRC-100 ecosystem already includes projects like inBRC, 100Swap, and 100Layer, covering areas such as markets, indexers, AMM exchanges, and liquidity protocols.

Programmable Runes ( Protorunes )

Programmable runes are an extension layer of runes that allow for the creation of programmable assets with runes. The Proto-Runes Protocol is the main project among them, developed by the team of the oyl wallet founders.

The Proto-Runes Protocol allows runes to be destroyed and converted into programmable forms called Protorunes through the Protoburn mechanism. It also introduces Protomessage for executing operational instructions within sub-protocols.

Currently, the first Protorune (QUORUM•GENESIS•PROTORUNE) has successfully completed Protoburn, and the development team is working on developing a WASM indexer. This provides a functional model for implementing on-chain governance on Bitcoin L1, allowing users to generate voting tokens through protomessage, achieving a transparent and effective governance process.