- BitVM, a Bitcoin innovation by Robin Linus, brings Turing-complete contracts without changing network rules.
- Community debates BitVM’s potential; some see it as a game-changer, while others are cautious.
A Bitcoin developer, Robin Linus, the leader of ZeroSync, has introduced a novel approach to introducing more versatile off-chain smart contracts to Bitcoin, all without the requirement for a soft fork. As detailed in a white paper released on October 9th, titled “BitVM: Compute Anything on Bitcoin.” This innovation, known as BitVM, allows the implementation of Turing-complete Bitcoin contracts while keeping Bitcoin’s fundamental consensus rules untouched.
"Any computable function can be verified on Bitcoin"https://t.co/Itf9UHos0C pic.twitter.com/CLQv49Ydsg
— 😸 яobin linus (@robin_linus) October 9, 2023
BitVM’s key breakthrough lies in its ability to express Turing-complete Bitcoin contracts, offering enhanced programmability on the Bitcoin network. Unlike traditional smart contracts that execute computations directly on the blockchain, BitVM focuses on verification, drawing parallels with optimistic rollups. This innovation can potentially revolutionize Bitcoin’s role in the cryptocurrency landscape.
The cryptocurrency community, particularly on platforms like Reddit and Twitter, is abuzz with discussions surrounding BitVM’s release. Some enthusiasts hail it as a potential game-changer, while others express cautious optimism. The proposal has even led to debates about whether BitVM could render altcoins obsolete.
BitVM vs. Altcoins: A Comparative Perspective
Bob Bodily, CEO of Bioniq Market, provides insights into BitVM’s capabilities. While acknowledging its advantages, Bodily points out that BitVM is slower, more expensive, and more complex than Ethereum’s Ethereum Virtual Machine (EVM). This suggests that while Bitcoin may become more Turing complete with BitVM, it may not entirely replace EVM for all use cases.
Sam Parker, Head of Technology and co-founder of Blockchain Transition emphasizes that BitVM enhances Bitcoin’s Turing completeness without requiring changes to its core consensus rules. He notes that Bitcoin is as complete as any other blockchain, making it “Turing complete enough” for practical applications.
One of BitVM’s significant advantages is its non-compulsory nature. Users who prefer not to trust their coins in a Turing-complete contract can choose not to. BitVM also has the potential to eliminate the dependence on centralized “Bitcoin edge” services, promoting fully trustless interactions in the cryptocurrency ecosystem.
Optimistic Outlook with Cautious Optimism
After reviewing the BitVM whitepaper, Taproot Wizard Eric Wall expresses cautious optimism. He highlights concerns about the setup phase, particularly regarding large pre-signed transaction exchanges. However, he eagerly anticipates real-world experiments to validate BitVM’s functionality.
Wall suggests that if BitVM efficiently verifies a zero-knowledge proof (zk proof) within it, it could assume the role of the zkwasm layer. This role entails a verifier appropriating a bond from a prover based on the result of a Turing complete computation.
The cryptocurrency community’s response to BitVM varies. While some, like Super Testnet, label it “the most exciting discovery in the history of Bitcoin script,” others, like Blockstream CEO Adam Back, are more critical. Back likens BitVM to Greg Maxwell’s 2016 zero-knowledge proof (ZKP) contingent payments example.
for people getting (over) excited, this is cool but effectively a generalization of a two-party game – it says right in the abstract – so it's a bit like Greg Maxwell's 2016 ZKP contingent payments implemented example https://t.co/OeHRsbFjud
— Adam Back (@adam3us) October 9, 2023
However, Robin Linus counters Back’s point, highlighting that in a ZKP contingent payment, the prover needs to know the solution upfront. This implies the superiority of BitVM over Maxwell’s 2016 ZKP example.
Challenges and Complexities
Despite its potential, BitVM introduces complexities and challenges. Developer Rijndael suggests that CTV (BIP-119 = Simple Covenants) could enhance BitVM’s efficiency. The consensus within the community is that while BitVM’s potential is immense, its real-world applicability and impact on existing systems remain to be seen.
Question about the challenge-response protocol: as i read it, vicky and paul would have to presign a challenge/response trace for each branch of the commitment tree at setup time?
— Rijndael (@rot13maxi) October 9, 2023
Maxim Orlovsky, from the LNP/BP Standards Association, praises the innovation but raises concerns. He notes that real-world programs, including zk-STARKS, require operations like multiplication and modulo division that are absent in Bitcoin script. These limitations stem from the restrictions imposed by BTC consensus rules. Practical results might necessitate years of development or even a soft fork.