Author: Bradley Keoun, CoinDesk; Translated by: Baishui, Golden Finance
summary
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, known as a “Rollup.”
Unlike earlier versions, BitVM2 is “permissionless,” allowing anyone to challenge suspicious transactions, not just a fixed set of operators.
Robin Linus, the bitcoin developer who shook up the crypto world last year with a theoretical way to make the oldest and most primitive blockchain more programmable, has unveiled a second version, “BitVM2,” that he touts as a major improvement that could bring the concept closer to practical implementation.
The basic setup involves using cryptography to compress programs into subroutines that can then be executed in bitcoin transactions, according to a white paper released Thursday by Linus and five co-authors.
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 Alexei Zamyatin, one of the co-founders, 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 really put into practice, 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 non-profit 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’s project was hailed as a breakthrough in part because it did not require any changes to the underlying Bitcoin code. This is crucial 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 modest proposals like the much-discussed OP_CAT have struggled to be adopted by maintainers of the Bitcoin code, as near-total 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 sparked 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 can be used to create blockchain “bridges” that can 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 (a method for confirming transactions that essentially involves data centers constantly solving cryptographic puzzles, consuming a lot of electricity) has been criticized for its impact on the environment, most blockchain experts agree that it is 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 to lock it up for. Now, it requires less capital and a shorter lockup time.”
