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The race to make Bitcoin programmable without a soft fork has been turned into one of the most creative weapons races in Crypto.
In the center is BITVM, a framework for proving off-chain calculation on Bitcoin via fraud tickets. The first iteration, now known as BITVM1, used an interactive protocol with several rounds. BITVM2 simplified this to a single-round error-resistant with the help of a split Snark verifier and is already practical for early adopters such as Build on Bitcoin (BOB), Citrea and Bitlayer.
Now BitVM3 proposes to go even further by saving the onchain fraud certificate with ~ 1000x. But there is a catch: it is still in the research phase, with critical security, complexity and data availability challenges to resolve before they are ready for production.
“The general design of the BITVM bridge between BITVM2 and BITVM3 remains the same,” Bob fellow founder Alexei Zamyatin told Blockworks. “The most important difference is to exchange the Snark -Verificator (BITVM2) with a mutilated circuit (BitVM3), he said, and added:” We are investigating the absorption of elements of the newest BITVM design in our customized hybrid BitVM bridge. “
Cooled circuits are a term for cryptographic gadgets with which one party can do a pre-commit for a calculation that can verify another without learning the private inputs. In theory, this reduces the onchain burden from Bitcoin to minor obligations per logical gate. Although it is a lot of promise, it is far from proven to scale and research is underway to tackle shortcomings before implementation.
Meanwhile, existing bridges are moving forward on BitVM2. Bob recently launched his latest BitVM2-based bridge test network with large Defi-partners to enable Bitcoin-supported assets in other chains. BITVM2 will be checked and is expected to be ready for Mainnet soon.
“One -coming circuits are an exciting development, but they still need a lot more research before they can be considered practical to implement,” Zamyatin explained. “It is important to note that the majority of the work to build a bridge with BITVM remains the same [when] using BITVM2 or BITVM3. “
The current costs of BITVM2 are not trivial: Zamyatin estimates a sausage case onchain fraud resistant with approximately $ 16,000 in transaction costs. But even that is cheaper than the Ethereum -Stack errors, which require 14 ETH or more (more than $ 40,000 today) for bonds, and can come across hundreds of ETH to actually prove fraud.
In the meantime, other teams are experimenting with different flavors of corrected circuits, as Robin Linus said in the BitVM Builders Telegram Group this week:
“Citrea onderzoekt een klassieke benadering van yao-stijl geringe combinatie in combinatie met een snij-en-choose methode voor het verifiëren van de correctheid van de circuits. Dat gaat ten koste van hogere communicatie- en opslagkosten, maar het is mooi eenvoudig en vertrouwt op zeer conservatieve veronderstellingen. In contrast, Alpen, Alpen, Alpen, Alpen, Alpen, Alpen, Alpen, Alpen, Alpen, Alpen, Alps, Alps [Labs] Investments a designated reporter Snark, who reduces the communication overhead, but is at the expense of more exotic cryptography, which is not yet hardened by the battle and does not work so well with ready-made tooling. “
In simpler terms, the Citrea method as the creation of many sealed envelopes (“corrected circuits”) that hides each step and then randomly let the Checker open a number of them (“cut and choose”) to confirm that you do not cheat. It is simple and built on proven ideas, but you have to send and save piles of envelopes, which is extensive and slow.
The Method of Alps shrinks everything in a single, small postcard (“Designated Verifier Snark”) that the checker can read quickly, saving bandwidth and space. The catch is that this postcard depends on newer, more experimental “cryptographic ink” that has not confronted as much Real-World stress tests and is not yet compatible with the standard stationery that most developers keep their desks.