Author: Bradley Keoun, CoinDesk; Translator: Baishui, Golden Finance
Abstract
The new "BitVM2" paper by Robin Linus and a team of co-authors marks a step forward from the initial design.
The project will rely on advanced cryptography and novel design to facilitate a secure "bridge" for transferring bitcoin from the main network to a secondary network (called a "Rollup").
Unlike earlier versions, BitVM2 is "permissionless," allowing anyone to question suspicious transactions, not just a fixed set of operators.
Bitcoin developer Robin Linus shocked the crypto world last year with a theoretical approach to making the oldest and most primitive blockchain more programmable. He launched a second version, "BitVM2," touting it as a major improvement that could bring the concept closer to practical implementation.
According to the white paper released Thursday by Linus and five co-authors, the basic setup involves using cryptography to compress a program into subroutines that can then be executed in a bitcoin transaction.
The program is then "verified" in three on-chain transactions, essentially ensuring that no one is trying to cheat or steal. In previous versions, verification could take 70 transactions, according to one of the co-founders, Alexei Zamyatin, who also works for a project called BOB, short for Build on Bitcoin.
A key improvement in the new version is that anyone can challenge suspicious transactions, a feature called "permissionless challenges." In the original BitVM, which was released in October but never actually saw real implementation, only a fixed set of operators could issue challenges.
"This design brings us a significant improvement," Zamyatin said in an interview. "We now have a comprehensive description of the BitVM paradigm."
Linus is a core contributor to the ZeroSync Association, a nonprofit organization based in the Swiss canton of Zug. In addition to Zamyatin, other co-authors include Lukas Aumayr, Andrea Pelosi, Zeta Avarikioti and Matteo Maffei.
Linus’ project was hailed as a breakthrough in part because it did not require any changes to the underlying Bitcoin code. This is critical because Bitcoin is more completely decentralized in governance than most subsequent blockchain projects; Bitcoin does not really have a guiding foundation, governing body, or lead developer like Ethereum or Solana.
Even seemingly mild proposals like the much-discussed OP_CAT have struggled to be adopted by maintainers of the Bitcoin code because near-complete consensus has evolved as the de facto standard for proposing updates.
A high-level overview of the BitVM2 protocol. (Linus et al.)
The initial application of BitVM2 is to enable “rollups” — essentially independent secondary networks on top of Bitcoin that can process faster and cheaper transactions, but with similar security guarantees.
The release of Linus’s original design spurred enthusiasm for projects building on bitcoin; as of July, CoinDesk counted at least 83 bitcoin Layer 2 projects in the works, with a variety of setups, including rollups and sidechains.
The new paradigm could be used to create blockchain “bridges” that could be used to securely transfer bitcoin to a rollup, and then securely bring it back so that deposits can be withdrawn.
While bitcoin’s proof-of-work consensus mechanism (the method for confirming transactions, which essentially involves data centers solving cryptographic puzzles nonstop and uses a lot of electricity) has been criticized for its environmental impact, most blockchain experts consider it the most secure blockchain.
This merit is underscored by the $1.2 trillion market cap of all outstanding bitcoins—more than all other cryptocurrencies combined.
“Our new bridge design is simpler and more capital efficient,” Linus noted in a Telegram message. “The previous design caused liquidity issues, both in terms of how much collateral the bridge operator needed to lock up and how long it was locked up for. Now, it requires less capital and a shorter lockup time.”
XingChi
