Earlier this year, Wei-Ken Chen With venture company partners L2 Repetition Chen decided to turn his attention to the rapidly developing Bitcoin ecosystem. A native of China, Chen had been noticing growing interest in Bitcoin development from several major players in the mining industry who had begun backing various projects in the Ordinalz and Layer 2 space.
“I had no idea Bitcoin had a development community,” he says, only half-jokingly.
Last week, an open source effort led by himself and backed by an infrastructure company was launched. Starkwareteeth, First implementation Zero-knowledge verifier using Bitcoin script.
In an industry where major breakthroughs have been few and far between, those involved in the effort are celebrating the significance of the milestone, arguing that zero-knowledge proofs are the key to unlocking bitcoin’s programmability and expanding its use on a global scale.
Behind this achievement is an incredible journey of an outsider who started Bitcoin development just six months ago and has now coded arguably its most advanced software. I interviewed Weikeng Chen to learn more about his motivations, his collaboration with Starkware around OP_CAT and STARKs, and his perspective on this new era of Bitcoin development.
Starting from scratch
Chen, who earned his PhD in cryptography from the University of California, Berkeley, explained that he began looking for opportunities to apply his technical skills to the industry to better position his company with potential investors and companies. Despite his extensive engineering experience, he soon found himself lacking resources and facing a steep learning curve. “A lot of the material out there is outdated and doesn’t reflect the current state of development.” His affinity for zero-knowledge technology ultimately led him to the study It focuses on Bitcoin’s ability to perform the computations required to verify zero-knowledge proofs.
Just as one rabbit hole leads to another, Robin Linus‘ Research on new computing paradigms Bit VM On his radar came the idea of using cheat proofs to implement a zero-knowledge system compatible with Bitcoin. Intrigued by the possibility of using cheat proofs to implement a zero-knowledge system compatible with Bitcoin, he began to look into the whitepaper and found some of the concepts included in the system problematic. “I sent Robin a message asking him some questions about BitVM. My understanding of BitVM from that whitepaper was, indeed, completely wrong. I remember Robin’s first reaction was to ask who told me about it,” he recalls with a laugh. This interaction marked the beginning of a brief but productive collaboration between Chen, Linus and other researchers, as they iterated on the original idea and looked for ways to optimize it.
“It was clear that this method could be used to verify zero-knowledge proofs, so my research quickly moved in the direction of implementing a SNARK verifier.”
Verifiers are cryptographic tools that enable the verification of zero-knowledge proofs on the Bitcoin network.
OP_CAT Opportunity
Around the same time, the team at zero-knowledge industry giant Starkware was noticing new activity coming out of the Bitcoin community. For some, it was a long time coming. Starkware founder Eli Ben-Sasson was probably First person to discuss We discussed zero-knowledge techniques in the context of cryptocurrency at early Bitcoin conferences, and now nearly a decade later, Starkware’s research and ZK-STARK technology is the foundation for a growing number of applications in this space.
“When I proposed the use of Proof of Validity to scale Bitcoin in 2013, I hoped Satoshi was still around to help us make it happen sooner. Thanks to crypto visionaries like Weikeng Chen and Bitcoin OP_CAT researchers like Andrew Poelstra and Ethan Heilman, my 11-year-old dream now feels like it’s within reach,” commented Ben Sasson.
Last month, the company Announced They have begun to develop a number of initiatives focused on bridging the technology gap between Bitcoin and zero-knowledge proofs. A $1 million application grant was provided to study and explore the potential of Bitcoin. OP_CAT Soft fork proposal.
The announcement generated a noticeable amount of enthusiasm, leading some to wonder what was driving the optimism. Until recently, the prospect of zero-knowledge technology in Bitcoin had been almost an afterthought, another piece of op-code that would never see the light of day. Indeed, the difficulty of reaching consensus on small changes to the Bitcoin codebase made anything more complex seem unlikely.
According to conversations with Starkware contributors, the atmosphere changed dramatically around May when they learned of Weikeng’s progress on BitVM. After all, developers were already turning to the company’s Circle STARKs technology. In a paper published a few months earlier, Chen had already positioned the latter as “a proof system suitable for Bitcoin.”
After some back and forth, the two sides agreed to work together to launch a collaborative effort dedicated to an open-source implementation of a STARK verifier using the OP_CAT primitive. “We knew it could be done; we just needed to put all the pieces together,” Chen says.Bitcoin Wildlife Sanctuary” born.
Two months later, thanks to the help of other developers like Pingzhou Yuan, an early BitVM contributor, the project appears to have achieved its goal. Late last Friday morning, Chen hopped into the project’s Telegram group to break the news to other participants: “I think the job’s done!”
After successful field testing, the developers A series of transactions The entire script has been implemented on Bitcoin’s Signet testnet network. STARK proofs based on Starkware’s open source STARK proofs have been adopted for optimized on-chain use. Stowe The implementation is split into concurrent transactions chained using OP_CAT-based contracts.
The final transaction was confirmed on the Signet network at 6:29 a.m. on July 12, 2024, and supporters believe this marks the beginning of a new era of development for Bitcoin.
“This was a huge effort and took a significant amount of time,” Chen said. “We started from scratch. Bitcoin had no information about ZK proofs. There was no information about the mathematical operations that go along with them. We had to build a full stack, which eventually led to our implementation of the STARK verifier.”
Paving the way for new development
While the achievement is worth celebrating, Chen stresses that the work isn’t done yet. When asked if he was optimistic about his work in building the foundation for new scaling protocols like Bitcoin Rollups, the developer was quick to dispel expectations:
“The idea is roughly working, but there is no proof of concept in production yet. Proof of effectiveness also requires a large amount of block space, which may become costly in the future.”
Starkware contributors acknowledge the challenges ahead, but are confident that the project’s success would represent a “groundbreaking step” towards a Bitcoin scaling solution that can leverage ZK rollup technology.
What is certain is that this collaboration is likely to further strengthen the arguments in favor of a potential OP_CAT soft fork. To put together the implementation of the validator, Chen said he needed to develop a reliable framework for contracts using CAT to highlight the versatility of the script improvement proposals. He believes other developers in the ecosystem can try out his code and come to the same conclusions as him regarding its merits.
“Once you have developed best practices, I don’t think there is much risk. There aren’t many places where this could go wrong. It has been clearly demonstrated that OP_CAT can be safely adapted to a variety of contract projects.”
When asked if they intend to contribute to the upcoming activation process, the developer candidly admitted that they are not yet fully familiar with the trends surrounding Bitcoin open source development. Next, they plan to share their progress with members of the development mailing list, in the hope that others can contribute to reviewing and providing feedback on their work.
Reflecting on his experience so far, Chen was quick to point out the importance of creating a fertile environment for new developers entering the ecosystem. He believes that the lack of a unified vision is causing many talented developers to miss out on the opportunity to build on Bitcoin.
“With no clear direction at the moment, contributors are left wondering whether they have the ability to influence the future. Hopefully, the emergence of new tools and primitives will improve this situation and allow bitcoiners to dream again.”
