Earlier this 12 months, Weikeng Chen and his companions at enterprise agency L2 Iterative determined to shift their consideration to the effervescent Bitcoin ecosystem. Chen, a Chinese language native, had taken discover of the rising curiosity in Bitcoin growth from a number of massive actors within the mining house who began backing totally different initiatives within the Ordinals and layer 2 house.
“I by no means actually realized Bitcoin had a growth group,” he says, half-joking.
Quick ahead to final week, an open-source initiative led by himself, with sponsorship from infrastructure firm Starkware, has achieved the primary implementation of a zero-knowledge verifier utilizing Bitcoin script.
In an business the place important breakthroughs are few and much between, these concerned within the effort are gushing in regards to the significance of this milestone. Zero-knowledge proofs, they argue, are the important thing to unlocking Bitcoin’s programmability and scaling its use globally.
Behind this achievement is the outstanding journey of an outsider who picked up Bitcoin growth simply six months in the past and has now coded arguably its most superior piece of software program. I interviewed Weikeng Chen to delve into his motivations, his collaboration with Starkware round OP_CAT and STARKs, and his views on this new period of Bitcoin growth.
Ranging from scratch
A PHD graduate from UC Berkeley with a specialization in cryptography, Chen defined he started looking for a chance to contribute his technical expertise to the business to raised place his agency with potential buyers and firms. Regardless of his in depth engineering expertise, he rapidly realized that assets had been scarce and the training curve was steep. “A variety of the fabric out there may be outdated and doesn’t replicate the present state of growth.” His affinity for zero-knowledge know-how ultimately led his analysis to concentrate on Bitcoin’s skill to carry out the computations required for verifying zero-knowledge proofs.
As one rabbit gap led to a different, Robin Linus’ work on the novel computing paradigm of BitVM got here onto his radar. within the potential of utilizing fraud proofs to implement zero-knowledge techniques appropriate with Bitcoin, he began poking across the white paper and observed some points with a number of the ideas concerned within the system. “I despatched a message to Robin asking a number of questions on BitVM. My understanding of BitVM from that whitepaper was certainly lifeless unsuitable. I keep in mind Robin’s first response was to ask me who had instructed me this,” he recollects laughing. This interplay sparked a quick however productive collaboration between Chen, Linus, and different researchers as they iterated on the unique thought and seemed for methods to optimize it.
“It was apparent to me that this technique could possibly be used to confirm zero-knowledge proof so my work rapidly went within the route of implementing a SNARK verifier.”
A verifier is a cryptographic device that permits the verification of zero-knowledge proofs on the Bitcoin community.
The OP_CAT alternative
Across the similar time, a workforce at zero-knowledge business large Starkware was paying shut consideration to the rising exercise popping out of the Bitcoin group. For some, it was a very long time coming. Starkware founder Eli Ben-Sasson was arguably the primary individual to debate zero-knowledge know-how within the context of cryptocurrencies at an early Bitcoin convention. Virtually a decade later, Starkware’s analysis and ZK-STARK know-how function the inspiration of a rising variety of functions within the house.
“Again in 2013, after I instructed utilizing validity proofs to scale Bitcoin, I hoped Satoshi may nonetheless be round and would make it occur quicker. Because of cryptography visionaries like Weikeng Chen and Bitcoin OP_CAT researchers like Andrew Poelstra and Ethan Heilman, my 11-year previous dream feels now inside attain,” Ben-Sasson commented.
Final month, the corporate introduced they had been starting the deployment of quite a few initiatives targeted on closing the know-how hole between Bitcoin and zero-knowledge proofs. A $1,000,000 software grant was supplied in the direction of analysis and exploration into the potential of the OP_CAT smooth fork proposal.
The announcement was marked by notable enthusiasm, leaving some to surprise what was driving this optimism. Till just lately, the prospects of zero-knowledge know-how on Bitcoin had been principally an afterthought — one other OP code that may by no means see the sunshine of day. Certainly, the issue of getting consensus over smaller modifications to the Bitcoin codebase made it appear unlikely one thing extra complicated would ever come to move.
Primarily based on conversations with Starkware contributors, it was round Could once they caught wind of Weikeng’s progress on BitVM and the temper shifted dramatically. As it will prove, the developer had already set his sights on the corporate’s Circle STARKs know-how. In a paper launched a few months in the past, Chen had already recognized the latter as a “Bitcoin-friendly proof system.”
After some backwards and forwards, each events agreed to come back collectively and arise a joint effort devoted to an open-source implementation of a STARK verifier utilizing the OP_CAT primitive. “I knew it could possibly be achieved. We simply wanted to place all of the items collectively,” suggests Chen. The “Bitcoin Wildlife Sanctuary” was born.
Two months later, the mission seems to have reached its objective due to the collaboration of different builders like Pingzhou Yuan, one other early BitVM contributor. Late morning final Friday, Chen jumped into the mission’s Telegram group to interrupt the information to different members: “I believe I completed the job!”
Following profitable native exams, the developer broadcasted a collection of transactions to Bitcoin’s Signet testnet community that might execute your entire script. To optimize on-chain utilization, the STARK proof, primarily based on Starkware’s open-source Stwo implementation, is break up into concurrent transactions chained collectively utilizing an OP_CAT primarily based covenant.
At 6:29AM on July 12, 2024, the ultimate transaction was confirmed on the Signet community, signaling what proponents consider could possibly be the start of a brand new period of growth on Bitcoin.
“This was an amazing effort and took a big period of time,” stated Chen. “We began with nothing. There’s no details about ZK proofs on Bitcoin. There’s no info relating to the mathematical operations to comply with. We needed to construct the total stack, which ultimately led to the implementation of the STARK verifier.”
Inspiring a brand new growth path
Whereas the outcomes need to be celebrated, Chen is insistent the job is just not achieved. Requested if he was optimistic about his work creating the inspiration for brand spanking new scaling protocols like rollups on Bitcoin, the developer was fast to tamper expectations.
“The thought roughly works however the proof-of-concept is just not production-ready. Validity proofs additionally take a number of block house which could grow to be costly sooner or later.”
Contributors at Starkware acknowledge the challenges forward however are assured the success of the mission represents “a monumental leap ahead” in the direction of Bitcoin scaling options that may leverage their ZK rollup know-how.
One factor is for positive, the collaboration is more likely to additional strengthen arguments in favor of a possible OP_CAT smooth fork. With a view to put collectively the verifier implementation, Chen says he needed to develop a dependable framework for covenants utilizing CAT which may serve to focus on the flexibility of the script enchancment proposal. He believes different builders within the ecosystem can play along with his code and are available to the identical conclusion he did relating to its advantages.
“I don’t assume there may be a number of threat as soon as we have now developed greatest practices. There should not that many locations the place that is going to go unsuitable. We now have a transparent demonstration that OP_CAT will be tailored to numerous covenant initiatives in a protected method.”
When questioned about his intention to contribute to a future activation course of, the developer readily admits he isn’t acquainted sufficient but with all the dynamics round Bitcoin open-source growth. Subsequent, he intends to share his progress with members of the event mailing checklist and hopes others will be capable to contribute assessment, and supply suggestions on his work.
Reflecting on his expertise up to now, Chen instantly factors out the significance of making a fertile surroundings for brand spanking new builders coming into the ecosystem. He believes many gifted builders are passing on the chance to construct on Bitcoin due to the dearth of a cohesive imaginative and prescient.
“There may be not a transparent sense of route proper now which leaves contributors perplexed about their skill to influence the longer term. Hopefully, the emergence of latest instruments and primitives can enhance this example so Bitcoiners are allowed to dream once more.”
