Scaling Bitcoin

Hi everyone, and welcome back to Stephan Livera podcast, brought to you by Bold. For American listeners, you can buy Bitcoin over at getbold.io. Now, joining me on the show today are Sims and David Seroy. Sims is the CEO and founder of Alpin Labs, and David is the ecosystem lead. So first off, welcome to the show, Sims and David. Thanks for having us. Having us, Stefan. Yeah, thank you. So we're gonna talk a bit about zk rollups, what does it mean for Bitcoin, and of course, what you guys are working on with Alpin and Strata, which I understand as your particular rollup. but, maybe let's just start with a little bit of the, I guess, for people to understand, what are some of the benefits? I know David, you, you did a, a whiteboard video, I had a, a quick look through that, and of course, listeners, I'll put that in the

Just so people can understand a bit of the why, like why I care about this stuff, what are some of the benefits of doing all this zk, zero knowledge rollup stuff?

Go ahead and take it. yeah, I mean, a zk rollup is an alternative layer two scaling solution for Bitcoin. many of us, I imagine that that listen to your podcast, Stefan, are very familiar with Lightning Network, and that is for a while kind of been the primary way that, that we look to scale Bitcoin. zk rollups are just an alternative way that offer a different

Something like sidechains, except sidechains were a concept that introduced essentially a second blockchain where you could bridge your BTC into them, and then perform more programmability and expressivity with your Bitcoin. the problem is sidechains never solved what was called like the trustless two way peg. anytime you wanted to bridge your Bitcoin into this other side system, you would essentially have to rely on an honest majority of, of trusted entities. The key breakthrough with zk rollups is we're able to drastically reduce that trust assumption. And make it to where it's what's called like a one of N trust assumption, where as long as one person is honest, then, the bridge is essentially secure. And this is a pretty profound, breakthrough and something that a lot of people are starting to get, excited about. And I'll just end this by saying that something like Lightning Network is, you know, hyper-optimized for kind of, fast throughput, you know, high transaction volume payments, but maybe it lacks in certain areas like expressivity and programmability. something like a ZK side of the trade-offs where you can add, pretty much abundant and infinite amounts of expressivity and programmability, but it does have other trade-offs like on the, the, the throughput side. so that's kind of a, a quick overview of, why zk rollups and what they offer.

Great. And so, I, I guess the point is to offer a different set of trade-offs in and out to, whether that's UX, programmability, scale, these kinds of, these are sort of the main- Things, and I guess some people may have heard of zk rollups, some of them might think of it as a privacy thing, some of them may think of it as a scalability thing, and then others might think of it as a they want, quote unquote, smarter smart contracts or some, some additional thing that can't be done at least today with what we have today on Bitcoin script natively in L1 Bitcoin, and that's why there's this, I guess, exploration and these ideas around, zk rollups. Now, maybe, I guess, a quick point just to maybe distinguish, because I think over the last, let's say, year and a half to two years, there was a lot of excitement about, quote unquote, Bitcoin L2s, right? There was a whole- New, you know, group of them that came up. Now, some of them were kind of seen as kind of being a bit of like a, a shitcoin thing or it was like a shitcoin rebranding. Do you wanna just explain a little bit about that and where Alpin Labs fits into that and, you know, just explain a bit of that aspect?

Yeah, absolutely, I can take this on. I mean, I think on your, you know, general question as well, like I, I see myself and, and also, you know, our, our, our team were really were Two things, like we're technologists, we like building and tinkering and, enabling sort of solutions, financial contracts, these kinds of things are really interesting to us of what, what can you actually do in a permissionless network? Can, can you really tinker around with it? At the same time, we're really, you know, we're Bitcoiners. We, we believe in Bitcoin as money, and, we think it's, it's the best money and that, you know, ultimately that is the The sort of, on top of that foundation is where the most interesting financial contracts and, and, you know, DeFi essentially or on-chain finance really builds out along with, you know, other, other kinds of use cases. And so, like that, that's, that's how we see this. And, you know, when we started this project, this was some time back now, you know, the, the folks on our team that, that wrote, you know, some of the earliest works on validity rollups of John Light published a paper on Bitcoin Rollups, dot org, I believe. I think that's the website. this was late twenty twenty-three, and even before that, Trey Del

Protocol engineers on our team, he, actually had the very first design around Bitcoin ZK Rollups. He worked on Lightning extensively, at the DCI and, worked on this new technology, and this was even earlier, I think, dates to twenty twenty-two. on the, the team as one of the, you know, founders here, when we were starting this venture, we sort of landed, You know, on this thesis out of, just like first principles thinking of, look, Bitcoin is, the most dominant asset, and there's going to be, you know, it's, it's gonna continue that dominance, and there needs to be a, a truly open platform that is programmable for the technologists like ourselves, and for, for many that have actually left to other ecosystems to be able to build and experiment with various types of contracts and so on. Some of those will win and some of those will provide, you know, what, what we think would be, for example, the best rates to borrow against Bitcoin or, or these kinds of really novel applications for the Bitcoin ecosystem. and our thesis sort of was You know, right now the sidechains are still like early and they haven't really solved that problem for a lot of these thinkers and technologists. And so we, we saw it coming from really a revolution two ways, one in money through Bitcoin and the other one in computation, in, in verifiable compute, which is, you know, another way of saying zk or, you know, validity proofs and this kind of thing. The idea that you can Actually, now, you know, take a program that, you know, arbitrary program that would take a very long time to run on a beefy machine and generate a cryptographic, you know, signature essentially, a proof that attests to that program running in, you know, in a valid way, means that you don't actually have to execute all of that program, you can just verify the proof, right? And this felt like, and this is not- New technology, it's been around for decades, but what we saw in that revolution was a rapid commoditization of, you know, it's cheaper, faster, more compatible than ever to be able to create these zero knowledge proofs, validity proofs is probably the right way to say it. There's also a privacy element to that as well. We're primarily, you know, using the succinctness property of- You know, turns out like, verifying, computation is much, much, much cheaper, almost fixed cost compared to actually executing a computation. And that plus Bitcoin made a lot of sense. Bitcoin's a ledger here, designed for money, designed to verify computation. You know, from the earliest Bitcoin forum talks, we saw this. And so we built this company around, look, these two revolutions are going to intersect here, and there's this really unique opportunity to build- really interesting types of layer twos, especially if we can get Bitcoin to reason about these, you know, cryptographic primitives like zero knowledge proofs. That's how we built out the, that, that was the origin really of, of the company. I think we were the very first team to raise, on a Bitcoin, rollup or ZK plus Bitcoin kind of thesis. and then after that was very surprising because I remember this is kind of during the bear market, we were trying to raise, there were some investors That it even said, "We love the team, it's, you know, four MIT co-founders, et cetera. Build exactly what you're building, but on Ethereum. Do another Ethereum L2." And we were like, "Absolutely not," and we didn't take some of that money. It was just unclear to the market at that time that this was like why this made sense. But as a result, we ended up getting some fantastic investors that really believed in Bitcoin in our seed round, six months later. This is now like a narrative essentially, right, in the ecosystem, of, wait, yeah, it does make sense, you know, like actually maybe rollups make even more sense in the context of Bitcoin than Ethereum. It's not just about scaling, it's all these other benefits like programmability and privacy that Bitcoin Layer One previously didn't have because of the script limitations. Yeah. And so-- And just to be clear,

sorry, on that point, from your perspective, do you see what you're building as mainly a scalability thing, a privacy thing, or, enabling smart contract? It's, is there an answer or is it kind of like a, a general purpose thing in your view? It is

all of the above, Stefan. I, I, I mean, look, it's not gonna be as scalable as Lightning. It's, it's not. Like, there's, you know, in terms of if you want the, like, full security of Bitcoin, there's an element of, you know, putting, DA or data availability on Bitcoin, which offers some, you know, benefits. We've run the numbers, it's, you know, thirty If it's, like, you know, you can have, you know, much faster confirmations, et cetera, that, that can be secured in different ways. But it's not gonna be lightning in terms of the scalability, but it's also, you know, dramatically improved in terms of the, the security from like a sidechain model that, you know, relies on a, a majority of multisig or something like that. So it's gonna be a lot more expressive, than lightning and, and an open platform, what that means is anyone in the Go and build really interesting things without touching like layer one or introducing new risks to layer one. They could do this on layer two, and zk is the abstraction where we can verify all of those transactions, put these signatures on Bitcoin, and, settle and, and inherit the double spend, security of Bitcoin essentially. And so it's, it's, it's, yeah, all of the above, but we're excited about, I, I, I think primarily, improving UX, improving privacy and, and just the expressivity and, and the--

Okay.

Op-opening this up to technologists essentially that have, previously haven't had, you know, gotten to tinker around as much within Bitcoin.

Got it. Okay. So let's try to overview a little bit of, you know, what it would look like in kind of layman's terms or in, in language that the, let's say, the intelligent layman can understand without necessarily being a, a super Bitcoin protocol nerd. and I'm gonna use the analogy of Liquid, just because people might have used, let's say, like Aqua Wallet on their phone, and so that wallet, as an example, keeps your balance in Liquid Bitcoin, and it uses kind of swaps in the background to do like Lightning and... Swapping and things like this. But essentially what that is, is when you, this user is holding liquid Bitcoin, it's custodied by the federation effectively. So in the liquid example, it's like, I think it's eleven or twelve or fifteen multisig, that's kind of who actually holds the Bitcoin, and what you hold is LBTC, and you're trading around inside the liquid ecosystem and swapping around with that. So I guess kind of a loose analogy is in this zero knowledge con- context, and I presume in Strata it's- Like this, that the user can kind of peg in to the zero knowledge system and also peg out of the, the near-zero knowledge system, and meanwhile transact inside of that ecosystem amongst other people who can so-called speak, you know, strata or speak that zero knowledge system. but the interesting difference is instead of it being a based on that eleven or twelve or fifteen multisig, it's actually based on this zero knowledge verifier And the idea is that there may, there may be a sequencer who's kind of collating some of those things, but they still can't lie to you, and the idea is that you still have, the user can still unilaterally exit. Is that broadly kind of the overview? Yeah, what am I missing there?

Yeah. I'll try to take a stab at this, just to, to kind of like set the stage for every single layer two. Conceptually, it looks like the same thing, where you're taking BTC that exists on the layer one, and you're locking it somehow on the layer one, and then you're representing that BTC on some sort of L2. In Lightning, you're representing it as, you know, Sats in the Lightning network. In Liquid, you're representing it as L BTC. In Alpin, maybe you're representing it as A BTC Some sort of activity will happen on this layer two, whether we're just transferring funds amongst each other or you're doing DeFi or you're doing like, it, it doesn't matter. Somehow there, there, there, there are some balances, like all of our balances on this L2 change. The fundamental problem with all L2s that make- Bitcoin difficult to scale is effectively an oracle problem. How do you relay that, hey, some action, some change in balance has happened on this L2, and how can you relay that back to, to, to, to Bitcoin? And we could just have, you know, we could say, okay, Bitcoin, we wanna add programmability to it, or we wanna make the blocks bigger so that I can understand and kind of grok what happened on this L2. But we can't do that because we don't want to, you know, cause centralization in the network, and Bitcoin, we, we wanna keep it small and minimalist. So, so functionally, it's, it's again, this kind of oracle problem where how do you represent what happened in the L2, any L2, back to the Bitcoin layer one? In something like Liquid, yes, they have this, this honest majority, this federation where you're trusting that the majority of the people will say, "Hey, Stefan, your balance is now this, I'm going to, you know, honor that on the layer one." In Lightning Network, every time you make a transfer, the two parties in the

Proof is a way to mathematically prove the validity of a statement, without having to recompute all that work. So if all three of us start changing all of our balances and doing all this work, Bitcoin layer one doesn't need to know about all the stuff that we did. It simply just receives the final result along with a zero-knowledge proof that proves that with mathematical certainty what your balance is. It, it, it proves to Bitcoin that All of the transactions that happened had valid signatures, or that there were no double spends, or, or that, or, or that all of these transactions happened in, in the right order. And so it allows us to have these arbitrary programmability environments of, of any sort of execution environment, or, or coding language that you want on the layer two. Bitcoin doesn't need to be aware of any of it. It doesn't care if you did Fartcoin and NFT and DeFi or whatever. It just says, "Look, mathematically prove to me that you If you did that, I really don't care. And that's the magic of a zero knowledge proof, is it, is it converts the scaling paradigm in Bitcoin from a computation paradigm where we're saying, hey, Bitcoin, you have to recompute all of this activity of Fark Coin and all this stuff, on these layers, to instead just a verification platform. Bitcoin just simply receives the zero knowledge proof and says, this is what happened, like, I don't need to know what happened on layer two, but here's the final state, check, we're, we're, we're done In this whole layer two boom that has happened over the past year, yeah, like frankly there is a lot of like grift still out there. And if you dive into many of these things, they're just multisigs by, by any other name. And they also, you know, are introducing new tokens that say, "Hey, we need this token in order to like create consensus or, or, or whatever." You know, fundamentally a ZK rollup, you know, allows us to kind of abstract away a lot of this centralization, not, not even abstract away, it like just Decentralization vectors, and then also not having to introduce, you know, new tokens for consensus where the gas fee or, or the fees are paid in Bitcoin, like Bitcoin is all, all, all, all you need. And so, yeah, like there's, it's sometimes hard to discern what's, what's real and fake, but zk rollups, I, I think- Are pretty much the closest thing we have to, to these like real breakthroughs in, in innovation and adding programmability, to Bitcoin. So I'll pause there for a second and hopefully that,

yeah, okay. And then just around kind of the mechanics of it, Sims, did you wanna, did you something? Well, yeah, I mean, I think you

had some, important questions there as well. I think we should really clarify this because especially as it relates to what, you know, what David said of- There's so many teams in this space now, and it's become a narrative, and it's sort of, you know, people are saying, "Oh, look, there's trustless this, trustless that, or unilateral exits here or whatnot." I, I just wanted to set the record clear in terms of where things are, right, with, with all the rollup stuff, and, and be, you know, upfront and honest about this, which is, We, we have a, a, you know, compelling solution that I think is production ready, and we are, you know, pushing this into production ready. That's what our team's been focused on getting this out into, into mainnet later this year, And the, the reality is today we still have, you know, certain limitations, right, on Bitcoin. We don't have covenant opcodes, we don't have, you know, and, and so- The design right now reflects, you know, that, that we're building and shipping to production is a significant improvement on the majority, you know, signers have to, in a multisig, have to be honest, et cetera, but it isn't a fully trustless solution, in that there is a one of N, like, you know, when we think about the, the BTC that's held right in, in the deposits, right, into the, the system, the BTC that's held on Bitcoin is put Into this N of N multisig, it's, it's locked in this N of N multisig contract. So what that means is if all N decide to, you know, collude, they could move those funds out. Now, the, the set of signers that, you know, folks we've been talking to are geographically located all around the world, a lot of them recognizable names, already, you know, important qualified custodians, et cetera, and so- Having at least one out of those n be honest in order for those deposits not to, you know, get moved out, is, is, is much better than a two of three, let's say, which I believe that's WBTC today or, or just, you know, fully trusting Coinbase alone on, on CBTC, we think that's a much better model already. and so we have to do this covenant emulation via n of n multisig, so that's one component of it, and it- It also, you know, means, you know, with introduction of some covenants, and, and our team has been already working on a, a lot of the research of like, okay, if we had this opcode, then how would we improve the design here or there? We think with, with most of the covenant proposals that are there today, we would be able to get rid of the, you know, n of n holding this on. But the reality is where we are and where really any team is, in this space, is that there is this one of n assumption, Exists, and what that means for unilateral exits as well is, you know, there's, there's a one of N sort of functional assumption on, on the withdrawals. So as long as one out of the N entities, bridge operators as we call them, are functional, follow the protocol, et cetera, then, you know, exits will, will be there. But, That is, that is the, the, the interesting

aspect of it. It's the kind of state of the trade-off, right? Yeah. Back to the show in a moment. This show brought to you by CoinKite dot com, the creators of the best Bitcoin hardware security devices, such as the Coldcard Mark IV and the new Coldcard Q. Now, we use Bitcoin hardware security devices to keep our keys offline, our private keys offline. Now, the way these work is you can do that setup, write down your twelve or twenty-four words on the, the seed word cards. And keep that secure. Now you can use this device to interact with the Bitcoin network using software such as Sparrow Wallet, Electrum, or Specter Desktop or Nunchuk as a few examples. Now you have a range of security features that you can use with these devices, such as passphrases. You can use Seed X or, or my favorite is multi-signature. Now if you're starting in a basic way, just start with the device and the USB-C cable, plug it directly to the computer and use it that way, and then later- Later improve your setup, but I believe these devices are great at helping secure your coins, especially as you start to migrate up into multi-signature security. But don't be disheartened or don't be, scared away. They are accessible, and I think you actually do learn about Bitcoin in the process. So to get yours, go to coinkite dot com, use code Livera to get a discount on your cold card. This episode brought to you by Galloy. They are building banking software for the Bitcoin age. So if you are with a bank, a fintech, or a... A startup looking to offer some kind of Bitcoin product, whether that is a Bitcoin collateralized loan, deposit accounts, or payments, Galloy can help you. Their latest product is called Lana. It is a loans management platform, and you can use this to come to market quickly and offer a loans, Bitcoin collateralized lending product for your customers. Now, Galloy have a lot of experience in the space. They started with Blink Wallet in twenty twenty, and they've since grown this to become a community favorite over time, and so they have a lot of experience Making things work in a secure, reliable, and scalable way. So if you need assistance coming to market quickly with a Bitcoin banking product such as lending or deposits or payments, talk to the team at Galloy. You can email them, the email is biz at galloy dot io, or go to the website galloy dot io. And now, back to the show. Gotcha. So I guess just to summarize then, the idea is it's like you could peg your Bitcoin into a BTC and trade it around. That the trade-off now, or the, the, the, the risk you're taking now, is that you're hoping that at least one of the bridge operators is honest. That's the main sort of trade-off we're dealing with, at least today with current technology and so on. Can you guys also touch on, now I know this is another big topic over the last few years, I did an episode with Robin Linus about BitVM, BitVM one, now I know there's BitVM two and there's been further work there, so could you explain a little bit about? How BitVM-- okay, let me put the question this way. How does BitVM change things for you with aBTC and, you know, zero-knowledge rollups? Yeah, I'm happy to take this, unless

David, you wanna chime in? but it, it's, Bivium one was, was really interesting, you know, when it came out. Initially, we had, frankly, kind of dismissed the paper when it had initially come out just because there was, there's a lot involved there and it felt like five research problems away, and we, we really cared about how do we bring this thing to production safely, right? And, and Over time, definitely, you know, we, we know Robin really well, the ideas definitely evolved there and we started putting our own work, we had a protocol called StarkNeto, which, one of the, the issues that we saw with the original design is like, well, you know, it's- It's this like back and forth challenge response game that like two entities have to play for Bitcoin to be able to adjudicate who the winner is. And it's this multiple rounds, I think it was like forty rounds, and it would-- each round's a week, it's like, you know, you're six, six to nine months at least, you know, for Bitcoin to be able to adjudicate the winner, which means withdrawals could be locked up for a while, for some of these operators, right? And so that was the first work that we'd done in terms of the Snark

And, you know, figure out a better-- and so we'd, we'd gotten that down to four rounds. and this was in twenty twenty-four, you know, spring, I think. and of course, you know, Robin, then came out with BitVM two, which is like, actually, you know, you could do this with a single round. And, and even at that point though, a-- and, and not just that, it could be, you know, permissionless in terms of the challenger, anyone can challenge, it but it was still theoretical, again, like it didn't seem like, okay, well, there's a big leap here. This is a brilliant idea that, that he had in terms of how to do it, just to be clear. But it's like, how? How does this actually work in practice? Well, there's a big like on-chain footprint whenever there's a challenge, there's, you have to put in like, like a, a, a ZK verifier on Bitcoin at that point was like close to ten gigabytes, I think. written in Bitcoin script, 'cause you know, you don't, you only have add, you only have, you know, you don't even have a multiply opcode, et cetera, right? And so doing a verifier for the zk, protocol in script was really big, and there were still some very important practical problems, and this was, I'm, I'm talking mid 2024 probably, here at that point. we spent a ton of time along with, it was incredible to see a, a lot of the open source community coming together. I mean, there's really people from at least a dozen time zones that are working on this around the clock, and have been for the last, you know, six months plus. But our team in particular, We, we, we, we ha-we published a couple of papers, one called "On Proving Pairings," another one on like field, you know, arithmetic in Bitcoin and, and so on. And our research engineering team, implemented a lot of those ideas that allowed, along with, you know, contributions from others, but a-l-a-allowed particularly for the verifier to like make it, you know, much, much more optimized at the point where You know, we, we really think that like the on-chain footprint at this point is, is, is production ready. It's, it's like the, the, the size of data that you actually have to put into Bitcoin in this bitVM2 protocol, which is essentially someone makes a claim about arbitrary computation via SNARK, and anyone can challenge that claim, and Bitcoin decides the winner within, you know, one to two week period, the whole protocol end-to-end. Is, you know, is, is pretty solid. It doesn't require, I mean, it fits with the Bitcoin constraints, it fits within the, the block sizes, and economically as well, it is, quite secure to where we're already talking with various operators that are going to be playing, you know, a role of, a, a bridge operator, putting, you know, some of these claims on chain, et cetera. And so, I, I would say the last like six months especially has been a huge push. From various teams, particularly from Alpen Labs, of focused on the verifier, how do we get this from, you know, how, how do we do like ten to twenty x optimizations on, on, on the script size, on, on everything, on the amount of data you need to put on chain? and that has been achieved. You can follow along with the BitVM repository, we're pushing out a lot of the code fully public, and, yeah, putting it there.

And so just to understand a little bit there. As I'm understanding, like, as an example, in the Lightning case, when you have a Lightning wallet, your wallet, like, keeps, you know, i-it's got its own version of what, you know, I guess colloquially known as a justice transaction, and the end user, like, his wallet can theoretically broadcast that to kind of reclaim, or he can, let's say, force close the channel to get it back. In this context, though, as I'm understanding, it wouldn't be like- Grandma on her phone is do- is being the challenger. In this case, I, I presume it's more like a professional operator, one of those bridge operators, is the guy who's gonna- challenge if there is a kind of a dishonest state being attempted to be broadcast to the chain. Have I got that right? Or can you explain a bit there? Yeah. The nice, it could be anyone, but yeah.

go ahead. Sorry.

No, Stefan, you're, you're exactly right. I mean, a lot of these mechanisms that we're describing, the end user, the normal retail user, even, even frankly like a power user, will probably never, ever even be aware, of any of this is happening. You know, they'll bridge onto the layer two via these kind of fast, cheap bridges, and if there's ever any issues with, with the kind of underlying bridge, yeah, it would just be these kind of, bit BM2 style games with the zero knowledge proofs, And, and, and nobody would need to be, the, the, the, the wiser.

I see. So as an example, even if people are familiar today, something like, BOLTZ dot exchange or, SideShift or SideSwap, these kinds of guys, they're the ones who are gonna be like helping people bridge in and out of whether it's maybe liquid on one side or Lightning on the other or aBTC on one side and LBTC on the other, and they're kind of gonna allow people to swap all between. And then at each of those companies

That's my understanding of it. Yeah. It's, it's

the, the peg, the one to one peg is set by the, the bridge that we're building, right? Like that's what gives, you know, the ABTC, as we're talking about, like value and, and, and holding the one to one. Now, once ABTC is available there, you can have, you know, trustless atomic swaps, as, as you're describing, a lot of these companies can facilitate like permissionless even trustless atomic swaps between ABTC and BTC in both directions. because you already have, you know, a pool of ABTC there, a pool of BTC there, and so anyone that wants to go in into the system or come out of the system, they can do so via these, you know- alternative swaps, they don't have to go through the, the, you know, the foundational bridge that we are building, and for the end user, the UX could be, you know, much, much better, much faster, doing so. it-- but importantly, actually, can we just on the, on the point of- Go, go on, finish your point. I just wanna ask another, go on. The, the important point of like, okay, then, you know, the natural question is like, why are we even kind of doing that bridge, right? It's, it's, it's-- it, there needs to be almost, think of it like, as th-this is what sets the peg to be one to one between, between the two BTCs, right? And then in terms of the- Like functionally how you get between each one of them, that could be done via multiple different options for the end user.

I see. And so just to, I guess, make it Tangible or a little more easy to grasp for listeners, if they are an end user, can you just talk through like what would that look like? Is it just gonna look like, you know, an app on your phone and I wanna send some ABTC to David, he shows me his QR code, I scan it and I pay it, or like, is it, you know, like what kind of UX? Is possible in this context.

I think it would look very similar to something like what people are familiar with, with Aqua Wallet, except it's just not trusted, it's not centralized. I'll also add that, you know, once you have something like a ZK Rollup where you can add expressivity and programmability, you can start building functionality what's known as like account abstraction. And so this is a, an extremely, extremely underrated aspect of having programmability, is like, for example, like on my phone right here. There is like a dedicated hardware wallet in here. There, there's essentially like a ledger or a treasure inside of here. But, because of the kind of restrictions that, that, that, that, that Bitcoin and, and Lightning have, like you really can't use that hardware wallet inside of your phone. But if you can add this expressivity to, to, to Bitcoin, then you could use, you know, face ID to securely, you know, scan your face and send transactions that way, or you can start, doing payments where instead of it's just being like, An invoice, maybe you could set up, you know, subscriptions where people could start pulling, from that. Or maybe, you know, you can, cover someone else's cost. If we're onboarding, you know, millions of people, we can cover their initial gas fees on their behalf. Or if people want to use stablecoins to pay gas fees, you, you, people can use stablecoins. So It's as a kind of baseline to recap, something similar to what people are, are, using maybe with like Alka Wallet, but it can be taken even to the, to the next level where we have world-class payment, UX that people are familiar with when they go to, you know, Cash App or Venmo or, or all these things, like all of that is actually possible without adding the centralized trusted, intermediaries, and that's- Even for the most ardent of Bitcoin maximalists, something that I think is, is, is hard to deny.

I say, yeah. Now, I think on the, going into the technologists, right? Like it's great for, like, someone wants to build the world-class UX and just abstract away all, all of the, you know, things to the end user, they can do that because there's more tools at their disposal. They can make, you know, authorizing transactions fully programmatic, and, you know, users can opt in to use such wallets. It's in services where, yeah, you could, you know, like to the end user, it's just like, hey, I authorize this thing to be able to take out this amount once a month. It's a subscription, right? And, and those experiences that, you know, all the tech stuff is abstracted away can be built in a clean way by, the, the technologists because with, you know, account abstraction, as David was saying, like you can programmatically, you know, you, you can program how authorization of that particular- account when, whenever they're sending transactions, how that actually works. And so it's just more tools at the developer side to create these kinds of experiences that allow, you know, for intuitive use, intuitive transactions, and, and new types of payments and transactions as well.

Interesting. Now, I guess one, maybe, maybe it's a counter argument, or I'm just curious to hear what you guys think. Isn't it gonna be really hard to build up another whole network effect, right? Think about Lightning. First, I think the white paper was from maybe 2015, if I recall correctly. The first mainnet Lightning was 2018, and even then it was very clunky. Even 2019, 2020, it was kinda clunky-ish. I mean, yeah, power users could do it and developers could

But there's been a lot of work to get it there. So with zk rollups, isn't this creating like another whole network effect that you have to start building up?

I would really challenge you on that, and I would actually say that it's, it's the opposite. You know, on these zk rollups, like right now, what you're able to bridge into, what we're building is an EVM compatible, rollup. you know, the EVM ecosystem has absurd, insane amounts of tooling, as much as we want to dog on it about like Kind of, you know, garbage and, you know, you have tokens and all this stuff. Like, the reality is, is there is, orders of magnitude larger network effect for the, the kind of tooling and the development, resources for EVM than there is for, for, for, for Lightning. On top of that, with this kind of power of, of ZK rollups, like you could even build, like other, execution environments. Like, there are things aside from Ethereum's EVM, there's the Solana VM, maybe there There's like Stacks as Clarity, there's, there's JavaScript based languages, there's pure Rust based languages, but the power of a zero-knowledge proof, you could take any existing network, a, a fact Where, where, where there could be, you know, millions and millions of, of, of developers and tooling, and with the power of a zero knowledge proof, you can program all of that in any environment that you want, and you can compress that into this succinct proof which can be verified by Bitcoin. So w-w-w-w-w-zk, like, definitively, out of all the trade-offs, this idea that, like, hey, you have to bootstrap an entire network effect, that is something that I, I think zk will, will, will, will dominate in. You can think of

Of like language and network effect, and we can compress that into something that, that, that, that Bitcoin can understand. So that idea of, of bootstrapping a new ecosystem, I think zk rollups has that in spades.

We can give tangible examples of this too. I mean, we've been doing a ton of partnership BD, sort of calls, you know, like on the, for example, like block explorer side, there's several different options that immediately integrate because they integrate not at the Ethereum consensus level necessarily, they integrate at the, like, they're compatible with the EVM A, as a language and execution environment, it could be oracle networks that have been around and safe for many, many, many years, most kind of distributed oracle networks, EVM, we, we can already integrate, we have audited code, Solidity works, RPCs, indexers, stablecoins that we've been, you know, some teams that we've been chatting with some of the top stablecoin issuers. Well, you know, we've, we've, we're familiar with the EVM, you know, we, we have code, we have, it's already audited, et cetera. You know, we might need like, you know, s-certain other, like, we might need a, a, a fireblocks, you know, on the custody side or something else like maybe analysis if it's a centralized stablecoin, right, for, for compliance for their side. All of these guys, again, we already, you know, are familiar with the EVM, if you're EVM compatible, the access to, integrate in all of those solutions is instant. And so there's this like industry around, like, it's like, I, I, I liken it to, like, yeah, JavaScript or something like that. It's, it's a language that is compatible already with a bunch of different companies, that, yeah, frankly, we do get to benefit from while, you know, using Bitcoin and being secured through Bitcoin.

Interesting. And so it's a fair point you make around, the compatibility with, you know, different, you know, ecosystems, let's say. so who would you say are the target users or who are gonna be the, let's say, the natural early users of this kind of- A product, or who are the first people who will actually be users of aBTC as an ecosystem, in this example?

What I personally would like to see is, is, I, I think what, what Bitcoin has definitively gotten right, over the entire rest of our industry is this, you know, commitment to, to, to money. Like, money is the core revolution, and I think breaking out of these kind of like degeneracy, just kind of, like, like, you know, recursive points and token schemes, like, I, I'm sure questionless system, but for us personally, like we want to break out of that and actually provide real world use cases to people that need stable coins, that, need borrowing products, that need wonderful like payment user experiences. Like the, the, the, the entire core revolution that, that Bitcoin was originally built on, you know, we, we think we can extend that vision and, and really go after that market. So for me personally, those are the first users that, that, that I wanna go after, people who actually need and value, money and as an extension of Finance,

yeah. And Sims, anything to add there?

Yeah, I just, I mean, maybe just to be concrete again, like I'll, I'll give like one example of an application we're really excited about, right? I think it's, Bitcoin backed borrowing, like, like borrowing dollars against Bitcoin, borrowing stablecoins, which can be off-ramped fairly easily into, into dollars liquidity if you want against Bitcoin, or you can use that as, you know, form of getting yield on the Bitcoin because it carries, you know, treasury rates, but you Vaults that, you know, provide, like the, the supply side for borrowers, again, which, which is additional yield, right, o-on the stablecoin. So I, I guess like anyone, like the, the lending protocol is really fascinating to me because, This is really big if you look at the use cases of, WBTC, for example, on Ethereum, I think that's like, the, the largest use cases, you know, tends to go towards, the, the Aves, the Morphos, Compounds, et cetera, where, people are essentially borrowing dollars against Bitcoin, they don't wanna sell Bitcoin, they want, liquidity, and it's one of those things which I, I really do think like on-chain is Like, you know, uniquely positioned to, to do better than sort of off-chain solutions. it, like, you have large composable money markets, right, with aggregated liquidity, and, and that typically yields more stable rates, more, more, Lower rates and, and better security as well. So your option as a Bitcoiner today is, I could go, in a, custodial solution or a collaborative custody kind of solution, and there are companies that are offering some great services there, but it's, you know, at like fifty percent LTV to, you know, fifteen percent interest or more to borrow against your Bitcoin. Or compare those to rates on, like, Morfo, for example, which is on Base and Coinbase had announced their big, like, Bitcoin back loans powered through, you know, Morfo on Base. That's at like six point five interest or some percent interest or something like that with up to eighty-six percent LTV, and I think it's at like four and a half

percent right now.

Is that right? Yeah, yeah, exactly. And so this is just gonna be much more competitive on chain, and, you know, this, model has been tested on Ethereum, right? You have, like- All the experiments have happened there, and we've been talking to some of those teams, and they're like, "Yeah, there, there's probably a bigger, much bigger market here on Bitcoin because BTC is the underlying ad- collateral." Right? Is, is, is really valuable for this kind of lending solution. Anytime we've seen, you know, like, most of the, you know, previous runs, we, we saw more custodial solutions emerge, those went away, but BTC was the dominant Collateral to borrow fiat against, and so that's a really interesting angle for, bitcoiners if they want the best rates with the best security. you know, of course, there's some really cool work going on with the DLCS, and I think, like there's alternatives, but I, I really do think the, ZK rollups will, you know, ultimately have the best rates to borrow against Bitcoin, and we're really excited about launching out that use case.

So I could maybe summarize it then in one way because there are already, Now, now setting aside, let's say, as you, as you mentioned, the, the, the unchain capitals and the leddens of the world, but there are a lot of people who kind of more in shitcoin land who are using, let's say, WBTC or CBTC, and I guess a lot of those users might come over to use this as well, right? Why wouldn't everybody

come over to use this? Like, it, it, it outcompetes virtually every other, Borrowing, whether you wanna talk about like TradFi, DLCS, WBTC, Letten, like Huddle Huddle, Unchained, like I, I think there's a compelling case where it's just like across the board, it's, it's, it's, it could be like a

white label version essentially, right? Or like a, a, a, you can, you don't need to take balance sheet risks as a company, you, you can plug in on chain, have the best rates with, you know, great security, and, and do this. And users like, alright, yeah, maybe I'll, you know, kind of, d-d-distrust like a more custodial BTC thing, or even trust like, you know, like CBTC, I'm fine with trusting Coinbase, that's fine, I'll, I'll go do it there. Sure, we think that, that exists absolutely, you know, like there's a, a, a chunk of the market that's like this, but like think about it now reverse from Other exchanges that, you know, that want to offer borrow against your BTC and get loans, the non Coinbase exchanges

who don't operate CBBC, are they

gonna wanna do that, CBBC on base, or, or, you know, like the WBTC solution that is, is again going through kind of more shaky governance, are they gonna want to integrate, like seeing how Coinbase is integrated into, you know, DeFi to offer that, you know, to their distribution to their users, Like there's interest in doing that because there's, again, less balance sheet risk, less, less operational overhead, and just the best rates. And so from the exchange side and the, the folks with distribution, if they wanna offer borrow against Bitcoin solution, they could plug in,

to,

to the L2 or to the

right. And it could be done kind of in the app for the end user, but actually the complexity is, again, managed by the service providers, the Bitcoin banks in this case, I guess. now, I guess on the risk side But of course, people will be thinking, "Well, hang on, haven't there been like bridge hacks and smart contract risk and these kinds of things? Is there a similar parallel here, or is it just, you know, there's just gonna need to be that time period for people to, let's say, get comfortable with this? It's a new context, right? It's a new concept, or I guess in some con-- in some ways, it's a new concept. How do you, you know, address that?" The vast majority

of, of issues I refer into are, That many issues as people would say, or like smart contract, risk. Well, like most of these smart contracts have actually been like pretty battle tested over the, the, the past few years, and now they secure, you know Billions of, of, of dollars. So I would say like the bridge and adding like some sort of like centralized, you know, entity to, to managing this bridge like is the biggest risk, and that's why, you know, we started this whole conversation with like BitVM and removing the, the centralization and trying to minimize the, the trust assumptions as much as possible and introducing this concept of like one of N, where as long as one party is, is, is, is trusted, then your, your funds are secure. So that is for sure the biggest issue, and that, Into kind of like pioneering these, these trust minimization of, of the risk. I'll, I'll just end this by saying like these, these protocols, things like Morpha or Aave or, or these kind of like smart contract or, as Stefan as you say, smarter, contract ways to, to, to borrow, like these things have experienced huge drawdowns of like seventy percent in, in, in the value of the collateral and they, and they've survived quite admirably. So while you always wanna build a, a deeper and longer Lindy effect, improve the effectiveness The, these things have been quite thoroughly battle tested.

I, I think folks are completely right to scrutinize like bridges. To be very clear, we scrutinize bridges. That's why we put You know, a, a, a ton of resources around how do we get better than an honest majority, you know, multisig kind of bridge? How do we push the frontier into less and less counterparty risk around the bridge? And at the same time, we're very aware, yes, like, you know, maybe the, the risk shifts more to protocol risks, right? If you're not, you know, less counterparty risks, but, you know, you're talking about kind of fancier zk sort of, you know, thing, there's probably inherently maybe more protocol risk. I think That, I would say, one thing that's interesting is if you look at, like, most of this bridge hacks and when people talk about bridges, it's been largely all these like centralized or like, you know, kind of multisig bridges that have been compromised in their keys, et cetera. it's been mostly that, right, in the last cycle, and, and a lot of that. and like we are, I think, hence, like, we're also very conservative team, generally speaking in this space, like we've been focused on mostly building, mostly auditing, mostly testing, and our teams, we're about thirty people, we have, you know, some of the best ZK cryptographers, not just within Bitcoin, but in the entire industry, on the team, that were, you know, previously formalists, have reviewed Like our research lead, for Bulletproofs, he found some issues, before he, he did formal reviews for all of those things implemented, a lot of that. And so we've strengthened our team, and our culture to go around You know, whatever we're pushing out in terms of the protocol, this is real people's money, and it needs to be a hundred percent as secure as possible and fully, you know, audited. One thing nice about Bitcoin though is because of how limited the scripting is in Bitcoin, it actually makes it easier to be sure, sure about, like, you know, the, the protocol Security, around it, like, on Ethereum, if we were settling on Ethereum L1, we're building Ethereum rollup, like, in, in other languages, they're just more involved and, and so there's like kind of more rooms for unknown unknowns, I think, i-in some of those languages. Bitcoin script is so limited, right, that it's like the, the surface area for some of those unknown unknowns is actually much more limited. And as a result, I think, you know, the, a lot of the work that we're seeing and we're starting You know, we think that like we can actually just build much safer systems when, when they're built on Bitcoin. and so, yeah, I, I, I would say, I, I, I think the design that we have right now definitely, definitely overcomes, a lot of the risks that we, you know, initially hadn't felt around the types of bridges that existed before, and to the full extent that, that we can, we're auditing, verifying, generating even cryptographic papers and security- Proofs around, o-o-all of the protocol related things to ensure that that side is also very safe.

The lead sponsor of this show is Bold, the best place to buy, sell, and save Bitcoin. For listeners in the US, Bold lets you secure your financial future with complete peace of mind by integrating a low fee Bitcoin only brokerage with next gen multisig vaults. With Bold, you can smash buy Bitcoin or set a DCA plan for only zero point nine nine percent fees and seamlessly deposit the Bitcoin direct to your Bold Vault. The Bold Bold Vault is a two or three collaborative multisig where you hold two keys and bold holds one as a redundant backup protecting against loss or theft. You can use Trezor, Ledger or Coldcard hardware wallets to spin up a Bold Vault in just a few minutes, and the Bold Vault is the only collaborative custody vault available with zero monthly fees. They're also offering zero fees on your first ten thousand dollars of Bitcoin buys and twenty five dollars of free Bitcoin when you buy a hundred dollars of Bitcoin or more. Try Bold today and upgrade your stacking experience over at GetBold. Gold dot io. And now back to the show. So a couple of things, just, you know, I think people would be interested because they may have heard these terms but not really know what they mean. So for example, this data availability problem, data availability, what does that mean? And how, how are you addressing that in your case? Sure,

I can take it. So, There are kind of like three, concepts like one is known as execution, one is known as like data availability, and the third is known as like settlement. And what a zero knowledge proof can, can compress is, is the execution or the computation. So a more tangible, I'll try, I'll try to make like a, a layman's example here, is like if you have transactions, like imagine just an Excel sheet and you say Alice sent to Bob, and then Bob sent to Carol, and then you have all of these- These, these transactions. The actual transactions themselves are like the, the data, and the, the computation is like the act of, of the brain or the computer saying, okay, Alice's balance was this, we have one transaction, now I'm updating it to, to, to, to this balance. So there's a difference between like the data of the actual literal transactions and then the act of like computing somebody's new balance. What a zero-knowledge proof can do is it can compress any amount of computation, this kind of act of computing The balances into a very, very succinct proof. You can get near infinite compression on, on that. But you, you, you, you cannot get this kind of infinite compression on, on, the DA, on the data availability. so there's only so much amount of compression that can do, go there. So there is still some sort of like scalability limit of, of how much of the DA you still have to post onto, onto, to Bitcoin. And this is the, the primary criticism of rollups. It's that That, yeah, sure, you can do EVM and SVM and all this stuff, and you compress the zero knowledge proof, but if you still have to post this data, which can only be compressed so much into Bitcoin, and we only have four megabytes every ten minutes, then you have an upper bound on, on the scalability throughput that, that can happen on Bitcoin. And so the, just with that, we go, okay, great, we get all this expressivity and we get like what Sims was saying earlier, like thirty to fifty x, throughput improvement. that's kind of the fundamental data availability, limitation. there are schemes, where you could post, The data availability on these non Bitcoin blockchains, and that can give you unbounded, throughput, but you're taking on some added trust assumptions. And this what, is kind of what makes the rollup conversation so hard when people say, "Oh, these things are bound by scalability," it's like, "Well, well, no, they don't have to be if users want to post their data availability on, on, on, on these other blockchains." But if they do that, then users' funds could be, they can't be stolen, If this separate data availability layer, is to be censored. So the, the, the kind of whole overview of this is there's a kind of menu of options that users can choose with their DA. They could opt for the highest level of security, but they're probably gonna pay more for that because you have to post it on Bitcoin layer one, or you can post it in these off-chain DA layers, but you risk some sort of added trust assumption. There's also a third option where you yourself could kind of self-custody or self-host your, your, your own data. So it Like whatever trade-off that you want, users can choose almost on a per transaction level how they want to, to, to, to handle that, that database level problem.

And so can you just explain for me how, what is the-- So let's say coming back to that idea, the end user is, is just gonna use the thing in like an easy app, but the, that operator somewhere at whether that's a large exchange or some kind of- swapping service, they are gonna have to deal with this DA problem. Where do you envision they would put their DA to deal with this stuff? Or are they-- or does it just look more like you, you see it more like the user is just gonna trust, let's say, that exchange or that swap provider to just host it themselves, to host their own, their own data?

Well, this, this, this depends on what timeframe. Like, when we go to mainnet, you know, probably in Q3, of, of this year, you know, we will just be posting all of the data directly onto Bitcoin Layer One to have the highest level of, of, of security and trust assumptions. But long term, it will kind of- The optionality will go to the users where they could say, "Hey, I want to have cheaper transaction fees, therefore they, they will kind of choose, through their own volition, like where they, they, they, they want to post that, that, that data." Does that answer your question, Stefan?

Yeah, so it's kind of just like naturally over time, you envision if there's adoption, assuming there is, then people will just kind of naturally push off to other cheaper chains per se.

Yeah, and, and, and, and I, I think even in, in the short term, like we run the numbers, you know, in Bitcoin, people may not be familiar with these terms, but there are other rollups on Ethereum, things like Base and Arbitrum and Optimism, and you could, in theory, even with Bitcoin's limited block size, fit all of those, like the top ten rollups in Ethereum, you could fit all of that transaction volume on Bitcoin. So in the short to medium term, like I actually think purely posting DA on Bitcoin is totally, viable. Have like, you know, one cent transactions, but it can definitely be competitive and it, it can fit. It's really just when we get to this global scale that then inevitably, yes, like there will be some amount of transactions that will have to go to this off-chain DA. And the analogy that I give here is, if you imagine Bitcoin Layer One is this bucket, you're essentially pouring water into the bucket that is data availability. The heavier transactions, which people aren't willing to compromise on the security and trust assumptions, will fall into that bucket of Bitcoin, and any kind of lower value transactions Will overflow,

overflow elsewhere, yeah. Exactly.

Yeah, so I guess can you, maybe

if you could explain just kind of roughly today or, I mean, not, I mean, not right now today, but kind of how much data are we talking per block? Like, can you give us an example? Or is, and is it, you know, how often does that data have to get posted? Are we talking every block or is it kind of a once a week or what's the period there?

Yeah, I, I think, on some of this, like, like so Roll up, and they'll have maybe different types of DA footprints on Bitcoin, right? And so, I, I, it's, I, I can't really, you know, share, you know, how much data or what that actually looks like. We will probably have a report on this and, and share kind of our, you know, expectations around some of this in terms of how often, we're posting, it'll be, you know, I think e-every couple of blocks, up until, you know, as everything gets more efficient on our We might post it as regular as, you know, kind of one block, but at the moment, I think we're doing maybe once an hour that we're posting on Bitcoin, on, on the, on the Cigna and Testnet, versions, It's, it's really like, I think the fee should be higher on Bitcoin, like it's, it's supposed to be used for settlement of high value, you know, Bitcoin transfers and, any financial transactions where the buyer's willing to pay for the security, and it is the pristine block space, you know, with, with the highest settlement and double spend security. I mean, this is really, really valuable and, and, and so we're opening it up for new types of activity that You know, allow users to say, "Hey, this is worth it for, you know, me to borrow against my Bitcoin, get dollars out, et cetera. I'm willing to pay the, you know, additional cost, even if it's a bit more expensive." and for the users that are, you know, it's a low, low value payment, et cetera, they, they, they can use alternative DA solutions still within this Bitcoin, framework, and, and they can do that. And so hopefully, like, competitive markets for fees and, you know, and, and real benefits for, miners, et cetera, as well with more activity that's secured through Bitcoin

Stefan, do you mind if I ask you a question? Yeah, sure. I'm curious your actual perspective on this because if, if there starts to be product market fit and usage for, for rollups, which we, we do expect, then, then yes, I imagine like pretty significant amounts of, of data will, will start to be posted to, to Bitcoin layer one and not these kinds of like ephemeral spikes like you'd see with like Ordinals and JPEG mints, but like, you know, consistent, strong, high fee pressure and like you could see the S

Or fifty or a hundred, but like, you know, you could see hundreds of, of, of, of sats per vbyte, and like that might cause, you know, some, some, some chaos in Bitcoin. Like, I think from our perspective, it's like, well, this could be legitimate use, like these are people actually using the rollup, for payments or maybe for privacy or maybe for borrowing or like, name all of your use cases, and you can essentially price out more of the kind of like spam type activities. But, like, like from your perspective, if Spam because it's from rollups, like, h-h-how do you think about this?

Yeah, it's a good question. I think, I think people would, if it were sudden, then it would kind of be like, "Whoa, what the hell's going on? What is this stuff?" if it were sort of like a gradual uptake over time, then I think people would just sort of naturally, just kind of, like, with that same overflowing idea or people just kind of naturally pushing off, like what we saw. I think is, when with all the, you know, retards and all the spam, we saw a lot more, let's say, lightning adoption, we saw a lot more, even people are now using Liquid as an example. So I think people will just kind of naturally kind of push off to whatever is next, some other cheaper way of doing a similar thing. Now, yes, in some cases, more people end up using Custodial. what can you do about that? I also think it's like we are, you know, not everyone can go on chain. We're just not gonna get everyone on chain. so, yeah, I, and also it is interesting now, as I'm sure you guys are aware, it's kind of funny that the fees are so low when, you know, price is so high, right? Even as we speak now, whatever, it's eighty-one thousand dollars per Bitcoin. I mean, it, it wasn't that long ago, right, at the depth of the twenty twenty So we're so much higher than that, and yet the fees are still pretty low comparatively, or relatively speaking. So, yeah, I think it's just gonna push more people to use, you know, Lightning, ARC, maybe ZK rollups, people will just use something else and, You know, I, I, I don't know. Now maybe the spam question could come up if it's like, you know, you know, non-standard transactions that aren't relayed by the normal Bitcoin nodes, this kind of thing. Maybe that, that could be kind of a, a contentious point in the community. I don't know. I, I, but I mean, for me, if it's, if it relates to monetary use I'm probably okay with that personally, but there may be others who are-- I don't know, maybe they, they don't see it that way. but for me, I, I find like the retardinal stuff annoying. Like, now, to be clear, I'm not a-- I don't believe filtering would stop them, and I don't really think filtering did stop them. I think it was more just they ran out of steam in terms of like paying the-- 'cause it was ex-extremely expensive to do that, right? It was just You know, I just think it was kind of like a fad, and we'll kind of look back on that the same way we look at Counterparty today from twenty fourteen or whatever. right. But yeah, it's an interesting question, what happens with if ZK rollups really do take off? But, you know, I think it'll take time. I think, the network effect question, I know we spoke about this, and your answer was that, yeah, look, we can already plug into, you know, EVM and Solana VM and whatever Which is fair, but then, yeah, I just think it just, I don't know, I, I, I don't have any predictions on how it all goes. I mean, maybe, maybe it does, maybe it doesn't. So I guess my, my, my short answer is, if it relates to monetary transactions, I think I'm okay with that, but if it kind of relates to like creating shitcoins and spamming the chain, then I don't like it, but at the same time, I recognize I can't really stop it. So yeah, so that's kind of how I'm seeing it. what, I guess one other question, because as, as we've spoken about today, yeah, and I think you've been quite clear to show, to show and say using, you know, BVM style techniques and these techniques and using your research, this is on Bitcoin today, right? This isn't actually requiring a new opcode, some kind of zk verifier, or I believe from one of your talk sims, it was OP As an example, right? Yeah. so could you just talk us through, like, what, I guess as an example, like the parallel, how I'm thinking about it is like the same way that some of the ARC guys are building out ARC without CTV or without TX hash or whatever, and maybe over time, if a lot of people use ARC, well, then there'll be a bit more impetus around, oh, hey, we should get CTV or we should get something like that. so I presume it's a similar thing here that if there's a lot of Z

Similar techniques in Bitcoin. What would that then mean in terms of like if you were to-- again, could be controversial for some listeners, but if you were to talk about, an op code to make it more efficient, what exactly would that look like?

Yeah. Yeah, as, as I sort of mentioned, I think or hinted at before, it's like I, I feel like there's the, the design space on Bitcoin, is already quite limited, so honestly, any of these opcodes, that, that are proposed right now would certainly expand that design space, and I, I feel like we can have a lot of creative ways to, like- You know, significantly maybe reduce complexity or even get rid of that one event or, you know, do, do other things. So, I, I would say I, I'm in favor of opening up the design space slightly, but not like incredibly, right, on Bitcoin. I think what makes it really interesting is, How it's designed, and, and, and for Bitcoin, I do think we need some form of covenants here, I, I think that would really help, reduce the-- get rid of, you know, having an emulation through an n-of-n multisig, and so, you know, insofar as like, I know there's, there's kind of recent interest around CheckSig from Stack, and, CTV, I think that combo is quite interesting and we're investigating how we would simplify our protocol. We think that a Happen with those. I think, you know, we've looked at OP_CAT before as well, and that particularly, you know, is useful because you can verify Merkle trees, you know, in Bitcoin Script if you have OP_CAT, and that's a, such a powerful primitive. It lets you, you know, do things with like Stark verification or it can, you know, other even other things like, you know, and, and I get like some of the, you know, comments about, well, you know, it seems small, but it's actually quite powerful. I think we've investigated it and like looked at all the kind of things that can be done, with Upcat, I think the other one that I'd really like to highlight is like big integer arithmetic, you know, just there's, you know, being able to do a little bit more math on, on, you know, would, would allow for verifying some of these like, you know, incredible cryptographic primitives like different types of snarks and starks, big integer arithmetic would be really helpful. Sure. and I like- Sorry, Sims,

I know you've got to run, so I guess we, we better wrap up, but, yeah, yeah, yeah. We, we better close it down. Anyway, I will put the links in the show notes, alpinlabs.io, and, yeah, thanks, David and Sims for joining me for, explaining some of this zk rollup stuff. Really interesting. Thanks for

having us. Thanks, much fun. Yeah.