S15 E65: Bitcoin Covenants Without Soft Forks with Avihu M. Levy of StarkWare
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0:47Vlad CosteaHello there and welcome to the Bitcoin Takeover Podcast. This is season 15, episode 65, and I am live right now talking about one of the most important breakthroughs we have seen in Bitcoin in maybe months. I think this is the hackiest thing since BitVM. It enables anyone to build covenants at a very high cost, but without a soft fork. And this paper came out like four or five days ago, and I got super excited. I was on a bus thinking about what I had previously written about OP_CAT and how that enables STARKs and stuff like this.
1:25And then I realized that everything that I thought I knew about this became obsolete. And I think this is the most exciting part of Bitcoin, if you ask me. It's more exciting than the price because that one seems more predictable in a way. It's just that I'm here live with one of the four co-authors of the ColliderScript paper. That's the name of it. The subtitle is Covenants in Bitcoin via 160-Bit Hash Collisions. His name is Avihu M. Levy, and he is a scientist at StarkWare, a company about which I guess you heard during the season 15 ads.
2:02And this is really exciting. It's really good to have you, Avihu.
2:06Avihu M. LevyThank you for having me, Vlad.
2:11Yeah, just one tiny correction. I'm no scientist. I'm StarkWare CPO. And yeah, I'm with the company from the very beginning. Very proud in what we're doing.
2:28Vlad CosteaYou also mentioned that you've been in Bitcoin since 2011.
2:32Avihu M. LevyYes. Yes, I am actively involved in Bitcoin since 2011. I spent— well, my background is in electrical engineering and physics, but I love the economy. And I actually got attracted to it back then because of, I think, two things. One is the revolutionary economical story and value and ideology that I felt very much connected with. And second, because I was a nerd and I wanted to do things myself. And this was a very beautiful opportunity. And I followed to be involved for basically ever since then. I actually want to start, Vlad, if that's okay, by just going over the story of how I see this idea or covenant in general in Bitcoin.
3:39So if you give me the opportunity, I will just go to that point in time.
3:44Vlad CosteaSure, go ahead.
3:45Avihu M. LevySo there has been a long time where Bitcoin scripts were limited. And they were mainly limited for me, from my perspective, by the lengths of what script can you enable. And what I mean by that is that, sure, there are many, many opcodes that are missing and were missing for a long time. But at the time where I took a first stab into checking covenants on Bitcoin, that was already a reality for a while. And before the latest upgrade, before Taproot, you had a very fundamental limitation of just the length of the script.
4:38So eventually, every creative thing that you would have tried doing, and people did try, and I tried as well, and I've seen what others have been doing back then, you can do beautiful things there as well. But the main issue is that you're very limited, you can go over a script of a very short size. And what that means is that while you can think and experiment with all kinds of tricky, hacky stuff, you probably won't be able to get so far because the script is limited.
5:14So for me, personally, my experience was taking a look at this four years ago, understanding that we need CAT, understanding that without CAT, there are complex tricks that we can do, but the length of the script will make them all probably prohibitively expensive and impossible. And just leaving it on the side. Fast forward to our days, I first heard from a founder of a company called QED, that people are now in Bitcoin in 2024, are experimenting with scripts that emulates various opcode. And tell me if I'm going too technical, but it's not important for the story.
6:02So this is not how I explain how things work. It's just for me to tell my point of view and my perspective.
6:09Vlad CosteaSure, go ahead. I'm also aware of Bitcoin OS, which is something that claims to emulate covenants.
6:15Avihu M. LevyYeah, I think the big, big change for me, but for other people as well, like Robin [Linus] and everything around BitVM and other directions that were taken, where the root of all those things was the Taproot change. Why? Because suddenly people could write scripts that were up to four megabytes long. And this was a significant increase in the script lengths and therefore a significant increase in the complexity that you could bring to Bitcoin. So Taproot on purpose or by accident brought back the scientists and researchers and people who are looking for innovation once again, because it allowed them to create much longer scripts and then play with a much more complex ideas that are using this capability.
7:14I'll give a very simple example. It's very much known that you can't do a multiplication straightforward in Bitcoin. The OP_MUL opcode has long gone and you just can't multiply two numbers straightforward. But you can emulate multiplication with addition, right? You can write a much longer script that will emulate multiplying two numbers with a lot of additions. That's something that you could do before, but will take a significant chunk of the maximal script size that you could have. And now post-Taproot, it's very straightforward to include it in a long script.
8:01And so people started to do it. So people went from, I can't do anything on Bitcoin to, hey, I can do additions, hence I can do multiplications, hence I can even emulate hash functions. And this opened the eyes, I think, for many people and many researchers to try and take a step in bringing back capabilities that were considered impossible back into Bitcoin. So I really want to point it out because I think the Bitcoin renaissance in terms of researchers is happening right now. And it is happening partially because Taproot enabled them to create meaningful new things.
8:44Vlad CosteaYeah, it's a lot of fun, actually, because there are quite a few people, including the Ocean mining cult members, I don't know how else I should describe them, who are saying that Taproot has actually ruined Bitcoin and there are too many non-monetary use cases coming to Bitcoin right now because of it. And I don't know what I should say, but I am happy that the builders are coming back to this chain and they're discovering how to do stuff that was previously possible only on Ethereum, but also in a more elegant way.
9:20Avihu M. LevyI want to stress that there are many serious people that are looking into all kind of various, very nice spectrum of improvements and new inventions and new research for Bitcoin, that they're looking on the traditional use cases as well, whether it's to improve payments or to improve swaps or to improve privacy. All those things will benefit eventually from this research. It's not going to be focused just as like creating this new atmosphere for a new cosmos of new use cases. That will come as well. But even for the simple, basic native use cases of payments and swaps and privacy, this is going to directly improve things.
10:16I can mention a bunch of people by name, but you are already familiar with them. They're working towards making those use cases, the traditional use cases, better, more secure, less dependent on third parties, more efficient, more scalable on Bitcoin. It's very clear. There is no doubt about that. And the fact that Taproot came and allowed long scripts, unlocked various things. It unlocked BitVM, it unlocked ColliderScript. People, we still don't— I can say it with a nice level of certainty. We still don't know all the things that Taproot unlocked, but we already know that it enabled us to have the complex operation that will eventually bring more cryptography, and more inventions and more researchers to create better protocols on Bitcoin.
11:15Vlad CosteaAnd that's pretty important. It's a big step towards hyperbitcoinization or enabling Bitcoin to be the dominant currency of the world. Because why is it better than gold or why is it better than any other asset? Because you can program it, you can do other stuff with it. And this technological edge is exactly what gives Bitcoin value. But some people forget about this when they curate and they make up their own narratives to explain why this is happening. But they disregard all of this cool building.
11:46But I want to take this back to your paper, which was published. I'm looking at the Cryptology ePrint Archive right now. It's paper number 2024, this is the year, slash 1802. So this is the paper number. The title is ColliderScript: Covenants in Bitcoin via 160-bit Hash Collisions, co-authored by Ethan Heilman, Victor I. Kolobov from StarkWare, Avihu M. Levy, which is you, from StarkWare, and Andrew Poelstra, who is the head of research at Blockstream, if I'm not mistaken.
12:23Avihu M. LevyThat's correct. So the story goes as follows. Like I said, I did look— after that, I did look into in what ways we can get covenants on Bitcoin today using this new tool of Taproot and large scripts. And I quickly realized that we have some sort of separation from one side. We have opcodes that enable things like hash computation straightforward and verifying signatures. Later, we call these those opcodes as a family, we call them large script opcodes. And at the same time, we have a long list of arithmetic or binary operation opcodes where you can do all kinds of tricks and computation like this.
13:16You can do addition, multiplication, you can emulate various hash functions, but you don't have access to the transaction signature with them. And then we call those small script. And the dilemma or the challenge was that if you want to enable covenants, you need transaction inspection. You need to know what is in the transaction that you are signing from within the script. If you want to know what is it in the transaction that you sign on, the only way in Bitcoin today to get this information is by proxy through the signature.
13:52And you have the signature. This is something the script is getting the signature. So the script has some sort of proxy to the transaction data. And this is amazing. This is great. We need that. Now, here's the challenge from one side, you have a bunch of opcodes that can access the signature. And for example, make sure it's a valid signature and therefore know that this transaction is being represented by the signature. But you can't really access any information or emulate the steps that brought the transaction data into the signature in any meaningful way in the large script world.
14:32But you can do it on the small script world. Just in the small script, you don't have a way to know that the information that somebody will provide you for the signature is the right information. So you sort of have two worlds. In one world, the big script world, you can say, hey, here's the signature. Let me verify it. This signature contains all the data that I need. The problem is that I have no capabilities to do introspection into the signature. That's the big world. And then have the small world.
15:03In this small world, I can get the signature data and the transaction data. And I can inspect the transaction data and check whatever I want and connect it to the signature. But unfortunately, I have no way to know that this is a valid signature. So I'm stuck. And those words, they couldn't communicate with each other. Big script world couldn't communicate with small script. So they couldn't tell each other from one side the big script, hey, this signature is valid to the small script. And from the other side, the small script to the large script, hey, the transaction data that is in the signature is what you want.
15:43So there are two separate worlds, no bridge in between. And what you want is that you want to find a way to bridge that this is a valid signature from the big script world to the small world, to basically to be able to say, hey, I know that in the small world, you are looking at the signature, just for your information, I verified it, and it's a valid signature of the transaction. And this is the basic of what you need. You need a bit more, you need some more verification to know that this is— actually the same signature, but this is the bridge that you are missing. You want the big script world to tell the small script world that they're dealing with the same signature. And if you have that, you have covenants. And getting into this, this basically observation was the just the core of now developing the idea, because now I know I need to show the small world from the big world that they're dealing with the same signature. How do I do that? And I don't know if to say it luckily or not, but the fact is that a big world, a big script world has only very few opcodes.
16:58So, and it's basically can only do signature verification or hash function computation. And so I was forced basically to go to the hash path. And then from there on, it was just a challenge to understand how do I make this bridge happen with the hash operations only? How do a script gets to the conclusion that it is dealing with the same element by just computing hash operations? And this is what the paper is about. I will stop here for a second. I know it was complex.
17:36Vlad CosteaOh, it's all good. I also want to take a step back and ask you about why covenants are such a big deal and why everyone talks about them these days. And why do we even bother with this? But before that, I got to present the show's sponsors for today, who are SideShift.ai. Oh, you just did your profile picture from Twitter, when you drank from the glass.
17:59Avihu M. LevyYeah, that's me. It's not by accident. Yeah.
18:03Vlad CosteaSideShift.ai, which is the place where, for example, if someone pays you in stablecoins, and we all know that it's a bad idea to hold stablecoins in the bull market, you can swap them on SideShift for free market money at pretty low fees. They have good liquidity, and you don't need to register in order to do the swap. So check them out. It's at SideShift.ai. Also, LayerTwo Labs, they're working on these drivechains, and they're pretty persistent in promoting an alternative way to push soft forks into Bitcoin.
18:37It's called CUSF. You can read about that. I think the website is cusf.info. And LayerTwo Labs also has a bunch of sidechains that you can try today on layer2labs.com/download. You're going to find the Zcash sidechain. You're going to have an Ethereum sidechain. And all sorts of stuff that you can basically try on the Bitcoin Signet. So check out layer2labs.com. And there's also Hodling.ch, which is a service from Switzerland that helps you with your self custody. So if you have a lot of Bitcoin, or you just got rich, and you don't know exactly how you should manage it to eliminate single points of failure, these guys can help you and explain to you if you need a hardware wallet, if you need a multisig, how you should proceed, how you should handle your backups in a way that keeps these attacks away from you.
19:31So also check out Hodling.ch, and of course, StarkWare. I guess you guys are sponsoring this episode. It's pretty cool. I gotta ask Nathan, by the way, because I had a call with him last week, and he told me I'm going very fast. And StarkWare is doing something really interesting with STARKs, which are ZK rollups that don't require any trusted setup. I know it sounds pompous and maybe a bit too technical for the average listener, but they're a big deal. And I think this ColliderScript paper is one way to get us there, except that it's super expensive right now.
20:12So let's backtrack a bit. We got to talk about why covenants are important, what StarkWare is doing with these, and why this ColliderScript is a good starting point to get there. I think it's a good structure.
20:26Avihu M. LevyYes, I agree. So I see covenants at this point, and that's my point of view, that the Bitcoin community has been discussing them for many, many years. I won't go into this long discussion, this by itself would be an episode. But the bottom line is that I feel that today, maybe just a step back for a second, covenant for me, from my perspective, means that we change a bit the part, the way Bitcoin operates today. When you look at Bitcoin transactions today, there is basically a very simple rule.
21:11It goes like this. You want to spend the UTXO, you need to know something. If you know this something, and this something can be very simple or very complex, but if you know it, anybody and anyone who knows it can take this UTXO and spend it however they like. The only exception are time constraints, but ignoring those time-related operations, what I said is just the way Bitcoin is operating today. And in particular, it means that you can't enforce a specific way to spend coins. You can't say, look, it's not just about what you know, but also about how can you spend them.
21:56And covenant adds another dimension. It basically says not only who can spend or what do they need to know in order to spend, but how can they spend. So it's a whole new dimension to Bitcoin. Bitcoin today is a single dimension, with covenant you get another dimension. And this gives you the ability to hold state, it gives you the ability to hold some sort of persistent logic on the Bitcoin chain, which sometimes has been called contracts. So the claim is that if you will be able to hold persistent logic on Bitcoin, you could improve scale, you could improve privacy in various ways.
22:39And the Bitcoin community has been debating what is the right, the best way to do covenant in a way that will be the safest, the least expensive, the most secure. And from our perspective, from StarkWare's perspective, we work on a scaling technology, and we work on STARK proofs. And we basically we work on STARK proofs to provide scaling technology. And for that to give a meaningful effect for Bitcoin transactions and Bitcoin users, there needs to be able to, there needs to, we need to have the ability to basically hold the state where we say, here are coins that belong to many people, just like a centralized exchange would do.
23:28But the difference is that the rules of how can you claim your coins and how can you transfer them are being executed elsewhere outside of the system, but in a way that nobody could cheat. And so this is different from centralized exchange that just hold your tokens and enforce the rules here. Nobody can cheat, including anyone who created the system or is operating it. And this requires in particularly this requires covenants. So, and I can, I can talk about an hour of about, like, I can talk an hour about covenants, but I get a feeling that at this point, most of the community are under the impression that covenants are good and desired property for Bitcoin.
24:17And the only question is, how do you get to it rather than do you want it? That's, that's how I see it. And Vlad, I will tell you the strongest evident I have for this is that on the course of a few— of a couple of months, like you said, we've seen BitVM, we've seen Bitcoin PIPEs, we've seen ColliderScript. Those are like three different papers that are, that are some sort of breakthroughs in the space. And they all involve in one way or another bringing a more complex solutions to enable scalability for Bitcoin.
25:00And they will all benefit or directly provide a way to do covenant or benefit from covenant. And my gut feeling is the reaction to those has been so strong, that it's probably a very strong indicator and a strong signal that the community as a whole are looking for those improvements. They are looking for people are looking for those inventions and breakthrough and research and improvements of Bitcoin. So that's my takeaway is that the community is interested and is ready in creating this layer and covenant is what will enable the really golden age for Bitcoin in terms of scale and privacy.
25:47That's how I see it.
25:50Vlad CosteaYeah, I mean, it's not about the covenant itself. It's just what you can build with the covenant.
25:57Avihu M. LevyRight. Yes. That's how I would put it.
26:01Vlad CosteaIt's just that the average user does not really understand how this will impact and how this will change the way that they use Bitcoin or what benefit it brings. I've actually heard concerns from people saying that these covenants, by the fact that they enable pretty much everything to get built on Bitcoin, they're dangerous because you never know when something evil is going to emerge and destroy the system.
26:28Avihu M. LevyYeah, it's a, this is an argument I've heard many times before. The thing is, I don't, for example, if I take Taproot, right, I can't, I don't think we could predict what exactly it would bring. People did their best to analyze, is it good for Bitcoin? Is it bad for Bitcoin? And at some point, there was a strong conviction to say, hey, I can point out on A, B and C, and A, B and C will all benefit Bitcoin. And I understand some of the risks. Of course, I can't, I don't have a machine in the inventory where I can say, now I look and I see all the possible futures, and therefore I can map all the options.
27:12But they basically, we as human, what we can do is we can try and debate and understand and research all the potential futures that we can see, and try to understand if the net sum is something that is good for Bitcoin. And if it is, do this change. And if it isn't, don't do this change. But I can't live with a claim that says, hey, we don't know what exactly it will bring, because we will never know what exactly it will bring. And there are bad presenters, but also good presenters.
27:43We need to eventually try to map our best, what, what are the good things and what are the best thing and then make a decision. And I can say that StarkWare, for example, took the path of like— and we did. We did talk about it before. We put on the side a $1 million budget for people to come up with researchers implementations that are showing both ways. Can you create good things with CAT? Can you create bad things with CAT? We are interested. Come to us, write us. Why do you think that or what can you show that will be good things you can do with CAT or bad things you can do with CAT?
28:33And we will give you a grant from this from this research fund, basically. And we put serious people on the research fund committee. And we are still, we got some very nice applications. I don't know if I'm allowed to say what they're about. But they're not necessarily like moon math things, or very future things. Those are particularly things that can improve the life of Bitcoiners today. So my answer to your question, Vlad, will be, you think you can present a bad outcome of CAT or of any other covenant like solution or a proposal?
29:15Come to us and we will give you a grant to actually present it or research it. And we are very serious about it. And this is this is how you get to a conclusion. You can either say at the end, I know what I'm doing. And it's pretty good things or I have a good understanding of it or not. But we need to spend time to understand those things. And I give the full credit for the Bitcoin community for doing that with covenant for the last, I don't know, four or five years already.
29:47Vlad CosteaRight, so I'm looking at the abstract of the paper of ColliderScript right now. It says we introduce a method for enforcing covenants on Bitcoin outputs without requiring any changes to Bitcoin by designing a hash collision based equivalence check, which bridges Bitcoin's limited big script to Bitcoin small script. There's also a mention here that to put this in perspective, the work to spend our covenant is about 33 hours of the Bitcoin mining network, whereas breaking our covenant requires 450,000 years of the Bitcoin mining network. So basically, to spend the covenant, you need 33 hours, which means 33 hours of mining blocks, which is pretty expensive, right?
30:33Avihu M. LevyYes, I do want to say in two minutes, the story behind this, because it will help put things in perspective. So it's actually a funny story. In April, like I said, I did look at it, I presented it internally, including to Victor Kolobov, which is one of the co-authors. He's a researcher and product manager in StarkWare. And he holds a PhD in cryptography.
31:08And I presented internally, we did a couple of rounds of improving that. And every round it got better. It started from 2^80 memory, which is not feasible, and then iterating on it, reducing the memory, improving the efficiency. And at some point, very shortly after that, I heard from Francis, our BD guy, that actually he heard in one of the conferences, Andrew Poelstra mentioning something about the same direction or idea, together with Ethan Heilman. So I immediately emailed them, I said, hey, I heard you guys talking about something of that sort.
31:54I do have something, would you like to talk about it? So we met over video, I presented to them, it was indeed in the direction that they were already looking. And we discussed about it a bit more, but then we didn't actually follow up on this. So I, from my perspective, I got to something that I was happy with, and then I just put it on the side. This was back in May. Maybe I proposed to present it once in some Bitcoin Prague event, it didn't happen.
32:27And then I just continued doing other things. And in July, Ethan— somebody asked on— probably Andrew spoke about it in some podcast, and he mentioned this idea, and then Ethan messaged me and he said, hey, what about we actually write this thing? We said, yeah, sure, it's a good idea. So I brought Victor, he brought Andrew to the picture, and we worked on it very hard and very long for another two and a half months to actually bring it to a form where it's not just a presentation or just a high level idea, but one that we actually specified how to create a script that you can actually use.
33:16So first, I think it's a cool story. And by the way, the reason why Ethan texted me was somebody asking about it over Twitter. So do ask questions on Twitter. That's one output— one outcome that I would mention. But what I want to say by this is the following. We spend some nice chunk of time to formalize this idea. We are 100% certain, I personally am, and I know Ethan has a good conviction, and I'm sure the other writers too, that this thing can be improved. Now, I don't know exactly by how much it can be improved, but my gut feeling is that it can be improved by a lot.
33:55Maybe it can be improved by a 50x. Now, don't take me at my word to say, okay, show me tomorrow how you can improve it 50x. But my gut feeling is that there are improvements on the implementation and on the off-chain part that can bring the cost down significantly. If the cost today is $50 million, maybe it can bring the cost down to $5 million or to $1 million or even to sub-$1 million cost. Maybe it can bring it down to even $500,000. So from one side, yes, for that, it will remain expensive.
34:33From another side, for example, for $500,000, maybe for some use cases that I cannot predict, people will already want to use it. Maybe people will take it a step forward and create hardware for using it. But even if not, I think that it has some significant contribution. So I just wanted to frame that what we have today is something that works and it's super expensive. And what can be done in the future, we can predict, but it definitely can be improved.
35:06Vlad CosteaYeah, of course it can be improved. But my follow-up question would be, did you build this just so you can prove what OP_CAT can do so that people trust you in enabling the soft fork? Because obviously you used a very good metaphor there with multiplications, that instead of having a function to multiply, you're doing multiple additions. And of course, that's more computationally costly and it takes more resources to do that, but you're able to do it anyway. So you prove that this can be done. You're showing the use cases.
35:42You're welcoming builders to use these collisions, these collider scripts, I call them collisions. And afterwards, if they like it, I think the conversation about OP_CAT or CTV or whatever other covenant can become much more serious because there are some real use cases around it and there are more efficient ways to accomplish the same goal. Would you say that this is the case and you built this only for the purpose of showing exactly what can be done in a very costly manner and to suggest that you can reduce the costs with the soft fork?
36:21Avihu M. LevySo first of all, I will be a hundred percent honest with you. I did it because it's cool and because it's fun. And I presented it to Ethan and Andrew and I can tell you that it has been, together with Victor, of course, it has been a great pleasure working with them. They're all very smart and they're all very fun and they understand very well how to balance between what is important observation, but also what is a fun thing, cool thing to do that they still don't know its implication.
36:57And brilliant. And they're all very bright minds and I would really want to collaborate with them more in the future. But yeah, the first thing is that I think myself, but also Ethan and Andrew, we just couldn't, and Victor, we just couldn't, it didn't make sense to keep such a beautiful idea in the drawer, right? Like we wanted the world to know about it as well. So that's the first motivation. I think it's very clear to me. Now on the side, as a side effect, I think people are now saying, Hey, well actually I have covenants today in Bitcoin.
37:35Now, obviously this is the thing people will come and say, Hey, Avi, what are you bullshitting here? Because covenants for $50 million aren't really covenants. Fine. I'm convinced we can push the cost down to around a million dollars or something like that. Would that be sufficient? Probably still not for 99% of the use cases, but then there is maybe 1% where it will be interesting. Maybe somebody will surprise us and say, Hey, I know this very cool method to improve that. If you do this computation of $10 million once or $50 million once now covenant will cost $10,000.
38:19I just don't know. Maybe this can come as well and it will unlock cool things. And it is, it is on the table. Like maybe this will happen. We can't predict what innovations will follow, but even if not, I think it does, like you say Vlad make people think because they look at one example after the other of various ways on how to achieve things without those opcodes, but with emulation or compromises on different things that are either expensive covenant or cutting edge cryptography covenants, or a pre-signed template instead of covenants to do things.
39:04And they want, it's very clear the community wants to do those things. And now they're just looking for a workaround. So here's where I put on the table, we put on the table, another workaround. So it's a, it's been added to the previous workarounds and it just, I think a stronger and stronger signal that we need something instead of all those workarounds that is straightforward, inexpensive and secure. And I think for many people, I did see Ethan Heilman's slide from a conference, OP_NEXT, that happened last week in Boston.
39:40And it's the same, the same gist of things. Basically we understand we want those use cases. Here are a bunch of workarounds. We're working towards all, creating all of them, but actually what we need is something simpler and secure. So that's, that's how we view things.
39:58Vlad CosteaYeah. That makes sense. And I gotta ask since, I guess you have to go in one minute or something. And I see StarkWare everywhere lately. You guys are attending conferences. You guys are funding a lot of research. You guys want to bring these STARKs to Bitcoin. And I've also seen people who are skeptical because there seems to be this trend whenever it shows up with a lot of money to build stuff in Bitcoin, they perceive this as some sort of outside attack or they're skeptical about the intentions.
40:30And I was going to ask you, what is the end game for StarkWare? What are you guys trying to accomplish?
40:35Avihu M. LevyI've been in Bitcoin, like I said, from 2011. Eli [Ben-Sasson] gave a talk that precedes everything we did in a Bitcoin conference in 2013. If we could, we would have built on Bitcoin a long time ago. I have the feeling that if I go seven years back, the community was not ready and the stage was not set for this technology to exist on Bitcoin. And like many things, Bitcoin does require you to iterate on your technology elsewhere or make it better before you bring the most concise way to do it.
41:16And it's very simple. What we would like to do is to enable Bitcoin and Bitcoiners to do things in a more scalable way, in a more private way, in a more secure way to unlock a much wider— a world with more opportunities for Bitcoiners and for Bitcoin. And that's why we are working in the Bitcoin space and that's why we're looking at it. And maybe now Bitcoin is more ready in various ways, in technological point of view, social point of view, the need to accept and to have this technology on top of it.
42:03Vlad CosteaIn the future that StarkWare envisions right now, would you say that Ethereum is going to coexist with Bitcoin and provide extra functionality or will Bitcoin completely replace everything that's on Ethereum and become the chain where everything is happening?
42:19Avihu M. LevyHard for me to make this kind of prediction, but what I do want to see is obviously more people coming in using Bitcoin and blockchain technology. And I think opening in Bitcoin, the scale, the privacy and broader aspect of execution will enable those people to bring their things there as well.
42:46Vlad CosteaOkay, final question. What is the shortest explanation you can provide as to why STARKs are important for Bitcoin?
42:56Avihu M. LevyIn Bitcoin and in blockchain, it's very, very important that everyone verifies their own integrity. And usually, you can't verify directly the integrity of too many things. And STARKs just give you the ability of verifying the integrity of many, many, many, many things. It's just one operation. So it's just like, instead of verifying integrity of the whole world, you verify integrity of one STARK proof and you're done. So that's in like one sentence.
43:30Vlad CosteaAvihu, thank you very much for this interview. For everyone listening, check out the ColliderScript paper. It's available online. And if you want to follow Avihu, he is @avihu28 on Twitter. Check out his work and keep an eye on StarkWare because they seem to be building a lot of cool stuff. Thank you very much. Thank you to everyone who listened to this on a very short notice on the livestream. I think we've had like 500 people watch this in total. And thanks to the sponsors for making this possible.
44:03I'll see you in the next one.
44:06Avihu M. LevyThank you, Vlad. Thank you, everyone.
