The creators of the Bitcoin scaling solution Bitcoin Virtual Machine (BitVM) have floated the second iteration of their sidechain, dubbed “BitVM2,” and the BitVM Bridge, which they say now offers “major improvements” to the original system. 

In an Aug. 15 post to X, BitVM co-founder Alexei Zamyatin shared an overview of a new whitepaper that introduces a new framework for how BitVM2 and the BitVM Bridge would function.

ZeroSync project lead and BitVM creator Robin Linus first unveiled BitVM in October last year in a bid to bring off-chain smart contracts to the Bitcoin network without requiring a soft fork.

Bitcoin sidechain creators tout new ‘permissionless’ version BitVM2 image 0 Source: Alexei Zamyatin

One of the main improvements of the latest version is that it will now be “permissionless” meaning that anyone can challenge suspicious transactions, with only three transactions required to complete a challenge.

The previous version of BitVM required up to 70 transactions to complete a challenge, and only a small number of specific parties could make challenge requests.

What does BitVM do?

Overall, BitVM2's main focus is to enable a rollup — a separate network built on Bitcoin — capable of processing transactions more efficiently but with similar security to the original Bitcoin network.

The BitVM Bridge would allow users to safely transfer their Bitcoin to the rollup and withdraw it, with shorter lock-up periods and smaller upfront capital requirements.

The paper was led by ZeroZync project lead Robin Linus and other co-authors, including Zamyatin, Lukas Aumayr, Andrea Pelosi, Zeta Avirikioti, and Matteo Maffei.

Bitcoin sidechain creators tout new ‘permissionless’ version BitVM2 image 1 BitVM2 offers “major improvements” to the original version. Source: BitVM.org

BitVM was unveiled in an Oct. 9 whitepaper titled “BitVM: Compute Anything on Bitcoin” — enabling Turing-complete Bitcoin contracts without altering any of Bitcoin’s consensus rules.

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The paper’s release inspired a wave of development on the Bitcoin network, with a swathe of Bitcoin-based layer-2 networks and rollups popping up in its wake.

Developers of the BitVM project have reiterated that BitVM is intended to scale the Bitcoin network rather than launch Ethereum-like decentralized finance (DeFi) applications on Bitcoin.

Pseudonymous BitVM developer Super Testnet told Cointelegraph in October 2023 that the overarching goal of BitVM was to increase Bitcoin’s scalability above all else.

“The real killer app is scaling Bitcoin. [Robin Linus isn’t] a big fan of smart contracts. He’s not a big fan of increasing Bitcoin’s expressivity. He really is interested in making it so that Bitcoin can process millions of transactions per second.”

He said he didn’t want BitVM to be flooded with EVM-like tokens because it would potentially attract bad actors to Bitcoin and said building a decentralized exchange on Bitcoin would be a “step backward.”

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