Title: S16 E4: John Light on ZK Tech to Scale Bitcoin & Make It Private
Podcast: Bitcoin Takeover Podcast (host: Vlad Costea)
Guest(s): John Light (Alpen Labs, working on the Strata rollup and its BitVM2-based bridge; Bitcoin ZK-rollup researcher; formerly built the BitSeed plug-and-play full node)
Published: 2025-01-16
Duration: 1:43:40
Episode URL: https://bitcoin-takeover.com/audio/?name=2025-01-16_s16_e4_john_light_on_zk_rollups_bitvm_alpen_labs_strata_-_16.01.2025_18.07.mp3
Audio: https://bitcoin-takeover.com/audio/media/2025-01-16_s16_e4_john_light_on_zk_rollups_bitvm_alpen_labs_strata_-_16.01.2025_18.07.mp3
Transcript: CORRECTED. Base: local Whisper medium.en transcript with automatic speaker diarization, reconciled against the YouTube auto-captions of the same livestream (offset about +5 to +18 s) and against a full local small.en (VAD) re-transcription with word timestamps (three-way comparison over the whole episode, rerun after edits). The base transcript's missing "Hello there" opening and a dropped clause at 00:06:30 were restored, a hallucinated "Thank you for watching." at 00:49:20 was removed, and the Mimblewimble/Liquid exchange at 01:08:54-01:09:32 (garbled and mis-split in the base) was rebuilt. Doubtful spots were re-transcribed locally from 11 short audio clips with medium.en (int16, VAD). At 01:10:11-01:11:14 John was accidentally muted for about a minute; that gap is marked in the text. Speaker turns were checked with a full-episode local speaker-embedding scan (TitaNet reference voices for Vlad and John, 1.5 s windows) and corrected by hand where needed (e.g. 00:15:13, 00:18:33, 00:26:30, 00:46:20, 00:48:06, 00:54:52-00:54:57, 01:09:11-01:09:24, 01:21:44, 01:22:16, 01:23:30, 01:24:29, 01:26:26, 01:27:22, 01:37:20). Sponsor reads are read live by Vlad and labelled as Vlad Costea. Names and jargon were checked against the title, the show notes and the web: Alpen Labs (alpenlabs.io), Strata (stratabtc.org), BitVM / BitVM2 (Robin Linus), BitVMX (Rootstock), BitSNARK, OP_CAT, CTV / congestion trees, Citrea, Arbitrum, Optimism, zkSync Era, Polygon zkEVM, BIP 300/301 drivechains and blind merged mining (Paul Sztorc), hashrate escrows (Sergio Demian Lerner), MEV, state diffs, data availability / data withholding, shielded CSV (Liam Eagen), Reth, Tornado Cash, Aztec, Railgun, Zcash Z2Z / full-chain membership proofs, Pirate Chain, Zooko, Litecoin MWEB (Andrew Poelstra, Grin), Liquid confidential transactions, BitSeed, Casa, Chamath, Umbrel, Jameson Lopp, Max Keiser, Taproot Wizards, Saifedean, LABITCONF 2023, S15E6 (with Super Testnet and Alexei Zamyatin), lightco.in / @lightcoin. Sponsors: LayerTwo Labs, SideShift.ai, Citrea, NoOnes.com, Hodling.ch. Intro music (0:00-0:45) omitted. Spots that could not be confirmed are marked [unclear: best guess].
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[00:00:46] Vlad Costea: Hello there and welcome to the Bitcoin Takeover Podcast. This is Season 16, Episode 4, and we are live with John Light, who now works for Alpen Labs. He is best known for doing research on ZK proofs on Bitcoin. I remember seeing him on the stage of LABITCONF 2023, which was like 14 months ago, if I'm not mistaken. And I was really impressed with the depth of his knowledge and the fact that he was so passionate about making Bitcoin scalable and private with this avant-garde idea in cryptography, which is zero knowledge proofs.

[00:01:21] Vlad Costea: And I'm really happy that I have you here, John, and we get to talk more about ways in which we can improve Bitcoin where it really matters.

[00:01:30] John Light: Great. Yeah, thanks for having me, Vlad.

[00:01:33] Vlad Costea: So what have you been up to? I remember I interviewed you back then. I published the interview in January of 2024. It was a four-way interview with Super Testnet and Alexei Zamyatin, and you were also in it. And you didn't talk too much at the time. You seemed rather shy. And I was thinking, you know, I should get this guy to join the show and talk more about what he's up to. And in the meantime, I think you also got hired by Alpen Labs. I don't think you were their employee at the time.

[00:02:06] John Light: Yeah, yeah, I was an advisor at the time, but I went full-time in April of 2024. So I've been working on product with Alpen Labs since then.

[00:02:18] Vlad Costea: So what's the product from Alpen Labs? I've also asked this question to Liam Eagen when he was on the show, but I guess you're the product guy. You're the one who describes it better.

[00:02:30] John Light: Yeah, well, right now we're working on Strata, which is a [unclear: ZK] optimistic roll-up on Bitcoin built using a cutting-edge technology based on BitVM2.

[00:02:47] Vlad Costea: Okay, I have some stuff to unpack from here. First of all, what is BitVM2 and how is it different from the original BitVM, which was published in 2023 by Robin Linus? And also, what's the difference between BitVM2 and something that the Rootstock people have developed, which is called BitVMX?

[00:03:09] John Light: Yeah, good questions. And yeah, there's definitely a lot to unpack there. So I would say the main difference between BitVM2 and BitVM1 is that BitVM2 enables permissionless challenging. So to understand or kind of grok the benefit of that maybe helps to explain BitVM1 a little bit. So BitVM1 introduced this new paradigm for programmability on Bitcoin, being able to program arbitrary conditions for how you can spend your coins, and it uses a so-called optimistic protocol to enable this. So the steps of the protocol are first you do a pre-signing ceremony with you and any other people who are participating in the protocol, and you pre-sign a bunch of transactions that define all of the different possible outcomes of the protocol.

[00:04:21] John Light: Like there's the happy path, which is like everybody follows the protocol correctly, and then there's the unhappy path where somebody, one of the participants, is trying to cheat the protocol or break the rules of the protocol. And what BitVM enables using time locks is this like challenge and response game to happen so that if somebody does try to, for example, move Bitcoin out of the BitVM protocol, like once you do the pre-signing ceremony this creates a Taproot address, and then everybody who wants to use the protocol transfers their Bitcoin into the address.

[00:05:04] John Light: And then if anybody tries to take Bitcoin out of the address in a way that violates the rules of the protocol as defined in the pre-signing ceremony, then a challenge period begins. And so this is, you know, it's like a configurable parameter, but let's say the challenge period is like a week long. This starts a period of time of like one week where any other participant in the protocol can put a Bitcoin transaction on chain that will stop the incorrect transaction from happening, like prevent the user from incorrectly withdrawing the Bitcoin.

[00:05:51] John Light: And then it can also slash some collateral that the user might have put up as like a bond to, you know, kind of as like insurance to ensure good behavior. And so it's a little bit like Lightning in that way. If viewers are familiar with Lightning, then you might know that, you know, there's this concept of like a justice transaction. So if your channel counterparty tries to broadcast an earlier state of the channel onto Bitcoin to, for example, like let's say that you open a channel together, they send you all of the Bitcoin in the channel. So you think you've got a bunch of Bitcoin on your side of the channel, but then your channel counterparty tries to, you know, broadcast that earlier state to Bitcoin before they sent you all the Bitcoin.

[00:06:43] John Light: This is kind of like trying to double spend in the Lightning context, but the Lightning protocol anticipates this and it creates this challenge period. And you have, you know, that challenge period where you can take this justice transaction and then put that on chain and like stop that earlier state from actually getting confirmed. And you get to take all of the Bitcoin that's like in the channel, even if it, you know, technically belonged to the other party at the time. And so this creates a financial disincentive against trying to cheat the Lightning protocol.

[00:07:20] John Light: BitVM has a similar concept. Like I said, you have this challenge and response game. But in BitVM1, only the people who participated in the pre-signing ceremony can actually challenge, you know, somebody who's trying to do an incorrect withdrawal from the address. In BitVM2, anybody can do that. So anybody can watch Bitcoin. If they have a copy of the rules of the protocol, then they can see if somebody is trying to put any transactions on Bitcoin that violate the rules of the protocol and then take some Bitcoin, fund the challenge transaction, and then stop the like invalid or, you know, incorrect withdrawal from happening.

[00:08:07] John Light: And in the context of what we're building, which is a roll-up, and we can talk about what a roll-up is if your audience isn't familiar, but essentially, it's like another blockchain that runs almost like inside of Bitcoin. But this BitVM program enables you to transfer your Bitcoin from the main chain into this roll-up chain. But the catch is that it's this pre-signing ceremony that was set up by what we call bridge operators that is actually securing your Bitcoin. So the operators do this pre-signing ceremony that generates a Taproot address.

[00:08:53] John Light: You send your Bitcoin to this Taproot address. And then you get an equivalent amount of Bitcoin on the roll-up chain. And then when you want to come back to Bitcoin, you create a withdrawal request on the roll-up chain. An operator is going to see that request, fulfill that request by sending you some Bitcoin. And then you've been fulfilled. You're out of the picture. Now the operator needs to get their Bitcoin back that they fronted to you. So they take a pre-sign transaction from the original pre-signing ceremony.

[00:09:24] John Light: And then they put that on chain, basically claiming, hey, I fulfilled this valid withdrawal request that was confirmed on the roll-up. I want to get my Bitcoin back now out of the bridge address. And if that claim is invalid, then anybody who has some Bitcoin can look at the state of the roll-up, look at the transactions that are going on Bitcoin, and say, hmm, something doesn't add up here, and then put another transaction on chain that stops that invalid withdrawal from happening. But of course, if the operator is following the rules of the protocol correctly, they correctly fulfill your withdrawal request, and they correctly try to reimburse themselves with the right amount of Bitcoin, then they're not eligible to be challenged, and eventually they'll get the Bitcoin back as well.

[00:10:15] John Light: So it's this whole kind of system for keeping different parties that are managing this transfer of Bitcoin back and forth between the main chain and the roll-up chain accountable to the rules of the protocol so that it's done securely. And it's worth noting that this kind of bridge is unique to BitVM. You can't build this kind of bridge any other way that we know of, anyways, using Bitcoin without BitVM. The other kind of bridges you might hear about, and you mentioned rootstock as an example, they just use a multisig.

[00:10:58] John Light: So it's a multisig. There are M of N, there are N number of signers on the multisig, and you're trusting M of N of those signers to keep the Bitcoin safe. And if they try to steal the Bitcoin, if they have enough signatures, they can just do it. Nobody can stop them. Whereas with BitVM2, anybody who has some Bitcoin and is able to watch the chain can prevent the operators from stealing the Bitcoin. So it's just a much more secure way of bridging Bitcoin. Another thing that you ask is, how does this differ from BitVMX?

[00:11:45] John Light: BitVMX works much more closely to BitVM1. So specifically, it does not have permissionless challenging. The only people who can challenge an invalid computation or withdrawal request in the BitVMX model are one of the participants in the original pre-signing ceremony. So BitVM2 is permissionless challenging. BitVM1 and BitVMX, and also this other protocol that's out there called BitSNARK, these all have permissioned challenging models. Only the original participants in the pre-signing ceremony can challenge an incorrect transaction.

[00:12:33] Vlad Costea: Right. But last year, when I was interviewing people about BitVM, I found out that most of the functionalities are very limited under the current design of Bitcoin. And it's preferable for BitVM to have something like OP_CAT to really unlock its full potential and enable it to maybe accommodate more users or cover more use cases, make it truly shine. And I want to ask you, does the current design for BitVM2 require any sort of upgrade to Bitcoin? Or does it work exactly as it is right now?

[00:13:10] John Light: Yeah, BitVM1 and its spinoffs, as well as BitVM2, all work on Bitcoin today. No soft forks required. There are some soft fork proposals that can improve various aspects of the operations of BitVM.

[00:13:36] John Light: But the protocol itself works as expected today.

[00:13:47] Vlad Costea: Okay, but what is the benefit that is added when you enable something like OP_CAT or CTV? I think Robin was suggesting something else at one point.

[00:14:01] John Light: Well, one of the things is that it can reduce interactivity. So, when you're first depositing Bitcoin into the system, it requires a lot of interactivity between the operators to do all of this pre-signing to set up all of the different paths that the transaction could possibly take. Once somebody is ready to withdraw Bitcoin from the BitVM address, and there are some soft forks that can reduce or even eliminate that interactivity, there are other soft forks that could enable permissionless withdrawals. So that anybody can actually withdraw some Bitcoin or initiate a withdrawal of some Bitcoin from the Taproot address, not just the bridge operators.

[00:15:01] John Light: So, there are some pretty significant UX or even security-related improvements that various soft forks could offer.

[00:15:13] Vlad Costea: Now, I want to ask you about something more specific, which is about one of the show's sponsors actually, which is Citrea. They say that they built the first ZK roll-up on Bitcoin. And also, I think to their credit, they brought some people from Ethereum to Bitcoin. And they also raised a lot of money for this, and they are hopefully also financing a lot of BitVM-related research. And I wanted to ask you, I've also asked this to Liam, what do you think about Citrea and how is it different from what Alpen Labs is doing?

[00:15:55] John Light: Yeah. Well, it's worth noting that there are no BitVM-based roll-ups like live on Bitcoin right now. So, I think claiming to be the first is perhaps premature. But they are building something that I think looks quite similar to what we're building right now. The Strata roll-up is an EVM-compatible roll-up with a BitVM2-based bridge. And Citrea is also an EVM-compatible roll-up, and I believe they also intend to use a BitVM2-based bridge. So, as of right now, I think it looks comparable to, you know, if you're looking like at Ethereum or something like that.

[00:16:46] John Light: And the roll-ups that exist there, it might be like the difference between Arbitrum and Optimism, or the difference between zkSync Era and the Polygon ZK EVM, or something like that. You know, it's like they're very similar technologies, but when you look very closely at the implementation details, you might see some differences. But, you know, I think it's too early to say right now like what exactly those differences are going to be once these systems go into production.

[00:17:28] Vlad Costea: Okay. I also want to ask you, because for a decade now, the idea of scaling Bitcoin has revolved somehow around this concept of creating a true sidechain. And in 2014, Blockstream came up with this concept of the sidechain. They didn't really take it, they didn't push it too much. They gave up and they released the federation, which they considered to be good enough. But the two-way peg sidechain was never really tried on Bitcoin. This show is also sponsored by LayerTwo Labs, and I very much admire the work of Paul Sztorc.

[00:18:05] Vlad Costea: I think that he's really pushing the right buttons to get people to consider what Bitcoin maximalism means and where this all leads, and how you can actually get Bitcoin to be useful as compared to just creating narratives around it. And I wanted to ask you, how would you describe the difference between the rollup and the sidechain, and what do you think about drivechains?

[00:18:33] John Light: So, the difference between a sidechain and a rollup is that, well, there are a couple of, I think, important differences. One is that a sidechain typically has a separate consensus system, or its consensus is determined by a separate protocol, a separate network.

[00:18:59] John Light: And so, a sidechain can therefore reorganize itself independently of Bitcoin based on forks in the chain that happen, whatever activity is happening with the miners over on the sidechain. Additionally, sidechains typically do not have a parent chain that is used for data availability. Sidechains are able to manage their own data availability.

[00:19:36] John Light: In part because they have an independent consensus system. Whereas rollups have their consensus tightly coupled with or even like inherited from a parent chain. Meaning that in order to reorganize a rollup, you actually need to reorganize the parent chain once a rollup block is confirmed. Additionally, a rollup uses the parent chain for data availability. So every time a block or a batch of blocks of a rollup is produced, the state of the chain at that particular block height is stored in a Bitcoin block or in the parent chain block, whatever the parent chain is.

[00:20:37] John Light: And this has like two benefits. One, as I mentioned, because rollups share consensus with their parent chain, it's just as difficult to reorganize a rollup as it is to reorganize the parent chain. And in the case of a Bitcoin rollup, that's Bitcoin, which means that it's just as difficult to reorganize a Bitcoin rollup as it is to reorganize Bitcoin, which is very difficult. It's the most expensive chain to reorganize right now. And then having data availability on Bitcoin is very valuable for rollups because it means that the data is highly available.

[00:21:20] John Light: Bitcoin nodes, there's tens of thousands of them around the world. And all of those full nodes, or at least the archive nodes that are storing a full copy of the blockchain, are also storing a full copy of any Bitcoin rollups. And that data is important for BitVM-based rollups in particular because you need that data, or at the very least the withdrawal data, in order to be able to challenge incorrect state transitions or incorrect withdrawals attempts from the BitVM bridge address. And so if that data was not available, then users wouldn't be able to construct the kind of like disprove transaction, which prevents the invalid or incorrect withdrawal transaction from ultimately getting executed.

[00:22:27] John Light: So data availability is really important for the security of the bridge in the case of rollups that have a bridge to their parent chain, and could also be really important for any protocols built on top of the rollup that also rely on strong data availability. Yeah, I'll stop there if you have any questions or clarifying points you want to go over.

[00:22:57] Vlad Costea: In the case of sidechains, you can have merged mining, which actually pays fees to the miners. In the case of rollups, can you actually have a situation where the transaction fees go to the Bitcoin miners?

[00:23:13] John Light: Yes, in two ways. One way is that you can define your rollup in such a way that block production rights on the rollup would go to Bitcoin miners. So let's say you need to produce a proof of work that's equivalent to Bitcoin difficulty in order to produce a rollup block or something like that. So almost like a merged mining kind of thing. There's also this mode of rollup block production that Vitalik Buterin once called pure anarchy, where anybody can produce rollup blocks. And at the limit, that means that your parent chain miners are going to be the default block producers, because they can just create the block and put it in their block to the exclusion of everybody else who's trying to do that.

[00:24:18] John Light: At first, it might be a competitive environment where lots of different people are trying to create blocks and stuff, but as the incentives play out, eventually Bitcoin miners are doing all of the block production. And then that way, again, it's possible. I would generally advise against it, at least for chains that might have high compute requirements or like lots of MEV or things like that, because this could end up causing some kind of centralization in Bitcoin mining if those centralizing forces end up leaking into, you know, Bitcoin, the Bitcoin mining world.

[00:25:12] John Light: And so the other way that the miners can earn fees from rollups is that, well, first off, there's just the operation of the bridge itself. Those operations pay fees, and those fees go to miners. And then the other way is every time a rollup block or a batch of blocks, depending on how the rollup operates, every time a batch is produced, it goes into a Bitcoin transaction and then gets confirmed on Bitcoin. And so, of course, that Bitcoin transaction has to pay for the block space it's taking up, just like any other Bitcoin transaction, and Bitcoin miners are earning fees from that.

[00:25:57] John Light: So it's not exactly like a one to one relationship between the fees that get paid on the rollup and the fees that miners earn, but it's definitely not nothing.

[00:26:09] Vlad Costea: Do rollups necessarily require their own token to be created and used as something for transaction fees? Or is that entirely optional?

[00:26:21] John Light: It's optional. You can build a rollup and just use Bitcoin. And that's what we're doing with Strata.

[00:26:30] Vlad Costea: The way in which I think about rollups generally is just like protocols such as Omni and Counterparty on Bitcoin. It's something that was added on top. It functions according to rules that are not known directly by miners.

[00:26:47] Vlad Costea: Actually, Counterparty is different because every Counterparty transaction is an on-chain transaction on Bitcoin. But in the case of rollups, you have a separate blockchain that has its own rules and its own features.

[00:27:01] John Light: Yeah. I mean, they are quite similar in the sense that they do both embed data into Bitcoin and then that data is interpreted by a separate piece of software in some kind of custom way. But I think maybe the key distinction between rollups and Bitcoin are that rollups have this block producer, like a separate block producer who's producing these blocks of transactions. And then only after they've created enough transactions for it to be worth it to create the Bitcoin transaction, then they'll like aggregate it all together and then put it on Bitcoin.

[00:27:44] John Light: And using ZK, which you talked about at the beginning of the show, they can even do some interesting tricks like highly compressing the transaction, removing all of the signatures, and then just proving using ZK that these transactions were valid according to the protocol. There were signatures on the transactions. The transactions did have all of the metadata that was required by the protocol. But after actually verifying that the transactions are valid, the signatures are valid, and so on, we can strip all of that metadata away and just come down to what are called state diffs, which is a very succinct or compressed way of encoding the data or formatting the data so that you just show Alice's balance went up two coins and Bob's balance went down two coins.

[00:28:52] John Light: And you just put that on chain, and it's a very, very small amount of data. It could be theoretically as small as 15 or 20 bytes per transaction. And for people unfamiliar, your average Bitcoin transaction that's just paying Bitcoin from one address to another is about 200 bytes. So it's like a 10x or like 90% savings on Bitcoin block space. Very, very good for scalability.

[00:29:30] Vlad Costea: I'm not sure I've heard your answer about your opinion on drivechains, both as described by BIP 300. And there's another way which was presented in a few Twitter spaces. And there was some musing about this, how you can generate drivechains using covenants.

[00:29:48] John Light: Yeah, I mean, I think it's an experiment that's worth running. BIP 300 is like one way to do it. And I think, you know, Paul Sztorc's idea is a combination of BIP 300 and 301. But there are also other ways that you can do like blind merge mining. And there are also other ways to do hashrate escrows, I think. Sergio Demian Lerner from Rootstock has his own draft BIP that proposed a different way of doing hashrate escrows. And so, you know, one way or another, I think, I think it's an interesting experiment to try.

[00:30:35] John Light: But these days, I focus on roll ups, mainly because I'm interested in enabling more functionality on Bitcoin, in as trust-minimizable of a way as possible. And if we have native ZK verification on Bitcoin, which isn't possible today, but could be possible with the soft fork, then we can actually have trustless ways of enabling new kinds of functionality, including new kinds of scaling protocols, new kinds of privacy systems for Bitcoin. In a trustless way. And I think that, you know, that's as good as it gets, right? Like, if the security of your coins is just as secure when you're opting into these new systems as it is like holding Bitcoin on the main chain today.

[00:31:32] John Light: Yeah, like that's as good as it gets. And that's what I want.

[00:31:36] Vlad Costea: You mentioned the issue of data availability, which I think is a fancy way of describing to which extent you can put your data in a block on the blockchain. And I wanted to ask you, what is your opinion on the idea of increasing the block size in Bitcoin to enable every user to unilaterally enter or exit one of these layer twos? Because it seems like people are super excited about covenants and the idea of using multiple UTXOs to put them on layer twos at the same time.

[00:32:14] Vlad Costea: But there is no unilateral exit. So if they do want to exit, they have to exit with the rest of the crowd that joined along with them. And I was curious if you think, of course, the long term vision for Bitcoin is to scale with scale with layers. But it's a good idea for users to afford to join these layers and exit them or switch to another one and so on. So I was wondering, what do you think about increasing the block size in 2025 when I guess internet is faster, storage is cheaper?

[00:32:47] John Light: Yeah, it's a good question. I'll answer it. But first, I want to maybe say a little bit more about like data availability and its importance, particularly for roll ups. Because I mentioned earlier in my kind of explanation of how side chains and roll ups are different that sidechains don't really have a data availability problem, or at least they do, but they have their own solution, which is that if a block is unavailable, you just ignore it, you can just fork around it. And you don't have to.

[00:33:18] John Light: It's not like a showstopper for the protocol. Roll ups are different because if you put a state transition on chain, and you include a proof that the state transition is valid, if nodes weren't checking for data availability, then this could actually create a scenario where users are no longer able to withdraw from the bridge. Because in order to be able to withdraw from the bridge, users need to be able to construct a valid zero knowledge proof, or a valid proof that they actually own some amount of coins in the current canonical state of the roll up.

[00:34:09] John Light: But if a state transition is committed, but not made available, well, users now do not have the current state and therefore are unable to produce a proof that they own coins in the current state. So it actually permanently freezes the ability for users to get their coins out of the bridge, and it could potentially even freeze operations of the roll up itself. And so what's called a data withholding attack is a pretty serious problem that roll ups would have if they were not storing their data in the blocks of the parent chain.

[00:34:56] John Light: But because roll ups by design are required to do that is something that they actually have to prove in the zero knowledge proof that comes along with each state transition. So when a roll up block producer produces a new block and puts that on Bitcoin, it's also including a zero knowledge proof that all of the rules of the roll up were correctly followed by that block, including the fact that the block is stored on Bitcoin in the canonical Bitcoin chain. And so if that proof is invalid, then that block is just rejected by the protocol and the users are going to wait for a valid block and proof to be created.

[00:35:48] John Light: But if the block is valid and the proof is valid, then the block is added to the chain tip and then the roll up progresses to the next state. So data availability is critically important for the security of the bridge, or at least the liveness of the bridge that users can get their funds out.

[00:36:13] John Light: Now, to go to your question about the block size limit increase, generally speaking, I think the block size limit right now is still low enough. Or let's say a block size limit increase from here to let's say 4 million weight units to 5 million weight units or 6 million weight units, something like that is probably fine for the network. It's been a long time since SegWit was activated, like eight years or seven or eight years now. And so, yeah, I think hardware has gotten better, bandwidth speeds overall have gotten better.

[00:37:01] John Light: It's probably fine to increase the block size limit a bit from here. But I don't think it's something that we can rely on perpetually to scale Bitcoin to the world. I think that there are other clever things that we can do to enable more users to self-custodially onboard and transact in Bitcoin without having to resort to just like brute force block size limit increase scaling to do that. Layer twos is definitely one way to do that. You point out an interesting challenge there, which is like, well, okay, let's say you onboard hundreds of millions of people to some layer two that's super block space efficient and does all these cool tricks to enable self-custodial or very close to fully self-custodial hodling of Bitcoin.

[00:38:08] John Light: But then something happens with the L2. The L2 service providers all disappear or there's some kind of game that people want to exit the protocol to go do something else. Whatever the case may be, you then have this problem, okay, a bunch of people are trying to exit the protocol. Maybe the protocol has a timeout period, so they have to be able to exit within a certain period of time or else somebody else gets their coins or something like that. And in that case, I think that, again, there are clever things that we can do like CTV congestion trees.

[00:38:48] John Light: There are things that you can do with ZK where you can actually enable users to migrate from one L2 to another without actually having to put their transactions on the Bitcoin blockchain. So, yeah, I think I would want to maximize the usage of some of the tools that we know already exist as well as maybe put our thinking caps on and try to think harder. Dev harder, build solutions that don't require actually increasing the block size limit to be able to safely support a larger number of self custodial users.

[00:39:36] John Light: I think that there's a lot that we can squeeze out there that we just haven't done yet. But yeah, I would want to see all of that stuff tried first before we kind of resort to block size limit increases because it does affect the economics of the system. It does affect decentralization.

[00:40:03] John Light: The bigger the blocks are, the harder it is to mine competitively and to run a full node. So I think that should be done very carefully.

[00:40:14] Vlad Costea: Right. You mentioned the term maximize utility. I'm not sure if it was utility, but the use cases. And I was going to ask you, what is your idea of what Bitcoin maximalism means? Because I see that the term went from what it usually referred to, which was this idea of one coin to rule them all. And all altcoins are experiments that try something that was proposed for Bitcoin, as was the case with Zcash, for example, which started from the zero coin proposal that was actually a soft fork for Bitcoin.

[00:40:51] Vlad Costea: And that was, I guess, the original thesis about Bitcoin maximalism. But it sort of went into this territory where being a maximalist means being a conservative who keeps making new narratives about why Bitcoin is great, and doesn't really want to maximize anything. Everything that was not already included in the protocol is a scam or shitcoin technology or something like that. And I wanted to know, what is your definition? Or how do you see this idea of being a Bitcoin maximalist?

[00:41:27] John Light: Yeah, yeah, what I was saying there was that you should maximize, like, our use of these kinds of clever tricks of like scaling self custodial usage, and even accounting for these like, mass exit kind of scenarios without resorting to just like block size limit increases, because I think that's a somewhat lazy way to deal with the problem.

[00:41:56] John Light: But to your question about Bitcoin maximalism, I typically just use the definition that was originally given by Vitalik, where he says that Bitcoin maximalism is this idea where, yeah, Bitcoin is the only coin that people should use, and that it is unethical for people to create altcoins or promote altcoins. You know, back when this was first, back when he first published this definition, I think there were some valid criticism that it was a bit of a straw man. Because very few people actually, like, believe such a thing.

[00:42:46] John Light: But, you know, he might have observed it in some, you know, some people characterizing the philosophy that way and kind of, you know, popularized it. And, you know, some people actually, like, took that kind of straw man definition and was like, yeah, that's, that's what I believe. And it kind of was almost like a self fulfilling prophecy. Where like that is what Bitcoin maximalism ended up being. But, yeah, I mean, definitions are fuzzy. I think different people have different definitions for what that term means nowadays.

[00:43:28] John Light: It's been over a decade since Vitalik first, you know, popularized it. So, yeah, it's morphed quite a bit since then. So, yeah, I don't think I could say, like, generally speaking, like, what it means nowadays. Different people probably have different ideas. I don't consider myself a Bitcoin maximalist. I wrote a blog post a couple of years ago saying, you know, I think if there is a term that would apply to me, it's probably something like Bitcoin pragmatist, which is like, if Bitcoin is the best tool for the job, use Bitcoin.

[00:44:05] John Light: But if something else is the best tool for the job, use something else. Like, I'm not going to, like, police what other people do with their own money, with their own computers, whatever. Like, they legitimately, you know, survey all of the options and they think something other than Bitcoin is the best tool for whatever job they're trying to do. I'm not going to fault them for using that other tool.

[00:44:32] Vlad Costea: Yeah. So you mentioned the article by Vitalik Buterin from 2014. It was called On Bitcoin Maximalism, I think. And I very much believe the context in which it started was that someone on Reddit posted something about Ethereum and said, whatever these guys are doing with Ethereum, we're going to just copy the open source code. We're going to copy the VM. We're going to copy everything that they think is innovative. And put it on Bitcoin Counterparty. And that was, I think, the fight that emerged at the time.

[00:45:09] Vlad Costea: It was Counterparty, which was running already on Bitcoin for a year, versus Ethereum, which was this fancy new layer one that was getting launched and was doing an ICO. And some Bitcoin community members were seeing something immoral in this idea of having a pre-mine and selling to investors before the network even launches and adding features that can already exist on Bitcoin. And I think this is where it comes from. This idea that, OK, whatever you guys are building there, we're just going to take it and put it and put it on top of Bitcoin.

[00:45:44] Vlad Costea: It's just that we didn't have that kind of scalability to include everything. And we're still wrestling a bit with how we're going to implement stuff on Bitcoin. I just hope we're not ossified yet, because that opens up the floodgates for a lot of altcoins to be 100% legitimate to use. And on this topic, I actually want to ask you, do you have any altcoins that you can mention as being non-scammy and are pretty legitimate and useful?

[00:46:20] John Light: I can only say maybe what altcoins I have used personally. And by used, I mean actually using for the utility, for the tech or whatever. I don't hold altcoins for speculative purposes, but I have used, for example, Zcash as a privacy protocol. I've used Ethereum for DeFi. I got a loan using Maker on Ethereum once and worked on a project called Aragon, which was building DAOs on Ethereum. And so, yeah, I haven't explored or used very many altcoin chains, but those are the ones that come to mind.

[00:47:14] John Light: I've bought some coins, I've downloaded the wallet, I've actually used it for its intended purpose or whatever. But I think other people have used other chains as well for their utility.

[00:47:33] Vlad Costea: It might sound like a silly question since you're working with zero-knowledge proofs, but I still have to ask it. Why did you choose Zcash over Monero?

[00:47:46] John Light: It's more private.

[00:47:51] Vlad Costea: But people will argue that there are fewer users on Zcash and therefore all that privacy gives you a much lower deniability because there is a smaller crowd in which you can hide.

[00:48:06] John Light: I think it depends on how you use it, but all else being equal, a Z2Z transaction is going to give you a much bigger anonymity set or crowd to hide in than a Monero transaction. In the shielded pool on Zcash, your anonymity set is like everybody who has ever used the shielded pool. And has not been fully de-anonymized. Whereas with Monero, your anonymity set is like, I think right now, 15 other people maybe.

[00:48:51] John Light: Per transaction, people do things like churning and other stuff like that to try to increase their anonymity set. But again, I think it depends on how you use it. But all else being equal, I think your random shielded Zcash transaction is going to be more private and offer better privacy guarantees to the user than a Monero transaction.

[00:49:23] Vlad Costea: I think Monero right now is trying to get the same amount of privacy with full chain membership proofs, but it's still something that they're working on. But also the technology that they use in the case of Monero, they're relying on block size increase and they have this dynamic block size and the transactions are pretty large in size with ring signatures. As in the case of Zcash, for example, the transactions are much smaller and they scale much better. And I think that's a good argument because they were able to make these Halo 2 anonymity pools.

[00:50:05] Vlad Costea: I'm not exactly what they call them, but the size of a transaction on that pool was approximately around the same size as a normal SegWit one-input, two-output transaction. Which is pretty huge given that around the time it was still called Zerocoin and it was proposed as a soft fork to Bitcoin, there were concerns that transaction sizes are too big.

[00:50:31] John Light: Yeah, I mean shielded Zcash transactions, Z2Z transactions are still pretty big. I think they're quite a lot bigger than a SegWit transaction. It's like a couple of kilobytes or something, but still you get amazing privacy from it. And of course, what I'm most interested in is bringing that level of privacy to Bitcoin so we can actually just use Bitcoin. I think altcoins in general are a short-term or temporary solution to people's problems. I think it's good that the solution exists. I'd rather have a solution available today than not.

[00:51:21] John Light: But in general, I treat them as temporary things because eventually you're going to be able to do the same kind of stuff on Bitcoin. And at that point, what's the point of the altcoin?

[00:51:39] Vlad Costea: Well, they're all experiments. I like to present this case because you have Zcash and people complain that it had the pre-mine, it had the ceremony, it has the foundation, it has all of these researchers who are on payroll. And they say, how can the future of money be the centralized entity or be created by the centralized entity? And that's a fair criticism. And there's Pirate Chain, which basically decided to fork Zcash and create their own chain that uses the same technology but doesn't have the pre-mine, doesn't have the foundation, is more community driven.

[00:52:17] Vlad Costea: And that's very nice, but they cannot keep up with the stuff that is being built on Zcash. And they're struggling to get the funding to actually keep up. And that's another issue to be presented because I think Zcash is the most interesting maybe science experiment that we have in this industry. It's the one that tries all the new cryptography and makes sure that it's packaged in a way that's usable. And for Bitcoin, I think that's also the most interesting research that can ever exist. And it's very hard to keep up with that.

[00:52:56] Vlad Costea: And it's also, I guess, the best way to describe it is that this is an experiment for Bitcoin. It's what it was intended to be. Zooko was, I think, the first person to blog about Bitcoin back in 2009. And Satoshi included his blog post on the Bitcoin.org website. He's a big time Bitcoiner. It sucks to a degree that he was erased from the history of Bitcoin to the point where most people just say, oh, he's that shitcoiner who's shilling Zcash. But at the same time, we have two scenarios.

[00:53:33] Vlad Costea: We have one where Bitcoin scales and becomes private and fixes all of its problems. And there's another one where it's remained stagnant for a long time. Mostly due to a lack of consensus. And all of these new actors who joined the space and they just want Bitcoin for the 21 million meme and nothing else. And they don't care about anything else. And that's why they also educate, quote unquote, the masses about what Bitcoin is and how it works. And in order to actually get some useful stuff, you have to print more money to create different networks with altcoins.

[00:54:12] Vlad Costea: And you're not going to have this 21 million coin future where everything is bought and sold for that amount of money. You're going to have maybe 200 million coins around the world that are being used for different purposes across different networks, maybe with bridges or exchanges in the middle. And I'm not sure which one is better and for what reason. But it's also scammy in and of itself to say that Zcash is on the same level as Terra Luna or Bitconnect or whatever.

[00:54:52] Vlad Costea: I don't know. It was just a rant.

[00:54:57] John Light: Sure. I mean, Zcash, you know, it does what it says on the tin. I mean, to be fair, Terra Luna did too. It's just I don't think people really thought that went through. But yeah, I mean, at the very least, like Zcash, it's open source. You can audit the code and you can see that the privacy protocol is working as intended. And so I think if you want like a very high degree of privacy for your transactions, it's a good choice. Monero could be a good choice as well if you prefer the trade-offs of that system.

[00:55:49] John Light: And yeah, like I said, I think the long-term outcome is that people are going to look out there in the world and see of all these experiments that people have been running, which ones look the most successful. And then can we bring the technology back to Bitcoin without the alternative currency? Because having to hold another currency that is maybe less liquid, maybe has a smaller user base, a smaller number of wallets that supports it, smaller number of merchants and exchanges and so on. Currency that might not have the longevity of Bitcoin, it's a risky thing.

[00:56:45] John Light: And so I think if people were able to kind of just consolidate their money into a single currency like Bitcoin, it's less risky and it's a better user experience overall. And so I hope to see the best experiments out there in the world come to Bitcoin in some way, some form eventually and trustlessly if we get a ZK verifier on Bitcoin.

[00:57:20] Vlad Costea: I was going to ask how much of Zcash's ZK technology is being brought to Bitcoin with these roll-ups?

[00:57:29] John Light: Right now, I'm not aware of anybody that's building a Zcash-style roll-up on Bitcoin, but it's certainly possible. Personally, I think I'm really interested in seeing Liam's work on shielded CSV come to Bitcoin, either directly on Bitcoin or on a roll-up. If that's how people decide to do it. But it shares a lot of similarities with Zcash just in terms of the level of privacy that it provides for transactions. But it does it in a more scalable way because on Zcash, you kind of have to put your full transaction details on chain.

[00:58:19] John Light: They're encrypted, so it's private, but it still takes up a lot of space on chain. Whereas with the shielded CSV protocol that Liam is working on, you only have to put a commitment to the transaction on chain, which is 64 bytes. So it's much smaller than even your average Bitcoin transaction, but you have a very high degree of privacy because your transaction details are end-to-end encrypted. You can still put the rest of the transaction details on chain if you want to and pay for that, but the system doesn't require that to happen.

[00:59:06] John Light: So I think it offers you the best of both worlds of keeping most of your transaction details off-chain if you want to save on costs or putting all of your transaction details on chain if you prefer maximum anonymity.

[00:59:25] John Light: You can get that full Zcash level of privacy if you want to, or you can save some SATs and just transfer the transaction data off-chain if you prefer that way.

[00:59:39] Vlad Costea: But in the rollup that's being built by Alpen Labs, is there any inherent privacy or optional privacy that users can have? Or is every transaction just as public as on the base layer?

[00:59:53] John Light: Right now all of your transac... it's all public transaction details because we are running an EVM compatible blockchain. So we take an EVM client called Reth and we just run that as a rollup on Bitcoin so it looks identical to Ethereum layer one. But you could in theory build optional privacy protocols on top. There are a bunch of interesting privacy protocols that have been built on Ethereum over the years. Tornado Cash is probably the most widely known, but there's also Aztec and Railgun that are also worth looking at. And it would be really interesting to see something like that come to Strata as well.

[01:00:45] Vlad Costea: Yeah, but I was gonna ask you this because I remember seven years ago or something people were complaining that Ethereum is just not good enough. And they were saying, you know, the EVM is a bad design, Solidity is a bad language. Maybe we should build this Ethereum killer. There was EOS, which I think was the most successful ICO ever, that promised to enable people to build with more programming languages. And there was also NEO and there was, I guess nowadays you just have Solana and Polkadot and a few others that are trying to do something that Ethereum doesn't.

[01:01:27] Vlad Costea: But how did it come to this phase where EVM is just accepted as being the best design and everyone is optimizing or building for that?

[01:01:38] John Light: Yeah, I don't know if anyone would agree it's the best, but it's certainly the most popular. And I think it's just momentum. It was the first fully expressive smart contract VM to ever launch. It had a lot of traction early on amongst developers for building smart contracts on chain. You have this accumulation of smart contracts that have been built over the years. So now you can kind of pick and choose, you know, the best performing smart contracts. If you want to launch a new blockchain, you can say, okay, well, somebody, if you launch a new EVM chain, you can just kind of look at Ethereum and say, okay, I'm going to take this DeFi thing and this multisig thing and this art thing and I can just copy that and then put it on my chain and it just works.

[01:02:48] John Light: And so I think it's, you know, it's the power of momentum, open source. And yeah, it's just a huge developer community. All the tooling kind of just works out of the box. It's just got this large amount of inertia and momentum behind it that keeps people using it. And it's, you know, like I said, I don't think it's the best, but it's good enough. And so people say, you know, even despite its flaws, all of the other factors that make Ethereum or the EVM in particular, you know, popular outweigh those flaws, like a lot.

[01:03:38] John Light: And so people will deal with the flaws to gain the benefits of like building within the EVM ecosystem.

[01:03:49] Vlad Costea: Yeah. And it seems like there's this migration from Ethereum into Bitcoin. I think it started with the ordinal inscriptions when people figured out a more efficient way to put data into Bitcoin blocks and also use ZK proofs to verify against the data that they inscribed. I think that's how we got these rollups, right?

[01:04:13] John Light: I would certainly say that there was some inspiration there. Yeah.

[01:04:19] Vlad Costea: Maybe it was the popularity of the inscriptions that gave people a confirmation that rollups can work on Bitcoin.

[01:04:29] John Light: I think the ideas were kind of emergent around the same time. Like once people realized that you could use these Taproot envelope data structures to store a very large amount of data inside of Bitcoin blocks, like up to a tenth of a block in a standard Bitcoin transaction. And up to four megabytes or close to four megabytes in a non-standard transaction. Yeah, it definitely got people's imagination going, like thinking like, well, you know, rollups store their data inside of the blocks of another blockchain. I can store 400k of data in a standard Bitcoin transaction.

[01:05:24] John Light: Like that's a lot of rollup transactions. And yeah, you know, got people thinking.

[01:05:33] Vlad Costea: Yeah. And also need to mention another sponsor of the show, which is SideShift.ai. If you have any Ethereum that you haven't exchanged for Bitcoin yet, you can do it on SideShift. They have pretty low fees and also really good liquidity. And if you're holding stable coins, that's generally a bad idea in bull markets. Not financial advice, but it tends to be a bad idea. So look into SideShift and see how you can exchange your stable coins or whatever coin that you hold and you think is not going to go up necessarily.

[01:06:06] Vlad Costea: And it's better to migrate back to Bitcoin. They have all the tools that you need to do the swap without sign up. And it's pretty cool. Check it out. And there's also NoOnes, noones.com. It's a website that's created by Ray Youssef. It's more than a website. It's a peer to peer marketplace where you can interact with citizens of the global south. So if you want to use some of the world's oldest currency, which is gift cards, and you want to engage in trade with people from the global south, go to noones.com.

[01:06:41] Vlad Costea: And Ray Youssef, who is the creator, defines this as a system where everyone eats. There is a small percentage that everyone along the line is making to have a small profit margin and keep the business going. So check out NoOnes. It's a pretty cool marketplace. You can sell some of the gift cards that you have or buy them or whatever you want with a bunch of coins like Bitcoin and Ethereum Litecoin, whatever. And speaking of Litecoin, John, your at on Twitter is L-I-G-H-T coin, as in coin in the sunlight or something.

[01:07:19] Vlad Costea: But I was wondering, what do you think about Litecoin, L-I-T-E?

[01:07:26] John Light: I don't think about it. No offense to that community.

[01:07:34] Vlad Costea: I think they have something cool going on with the Mimblewimble extension block. That's what gives the chain legitimacy because Andrew Poelstra proposed that in 2016 for Bitcoin. It was never implemented in any shape or form, but these people picked up the idea and they coded it. They brought this developer from Grin and they made it happen. And now they have the extension block with privacy, which is really cool. Honestly, if you want to swap between privacy coins and you want to sell on exchanges, I think Litecoin is the best way to do this.

[01:08:12] Vlad Costea: If you go into the extension block and then peg out from it to the exchange, I'm not aware of any exchange that's going to deny you this as opposed to Z addresses on Zcash or Monero.

[01:08:28] John Light: Is their implementation of Mimblewimble actually private? Because other implementations that I've seen, I would better characterize it as a scaling protocol than a privacy protocol. Because you can watch the peer-to-peer network and reconstruct the full transaction graph of what everybody's doing.

[01:08:54] Vlad Costea: Well, you still have the confidential transactions, even if you can figure out the inputs and the outputs. So, even if you know who sends to whom... Oh, you think you can see the amounts too?

[01:09:11] John Light: No, I said Liquid has confidential transactions too.

[01:09:17] Vlad Costea: Yeah, but they're optional. I would be curious to see which percentage.

[01:09:21] John Light: That's the MWEB side block, right?

[01:09:24] Vlad Costea: That one has, by default, you can't opt out of privacy on the extension block.

[01:09:32] Vlad Costea: Yeah, anyway, it's interesting to me. You can swap from Monero into LTC on MWEB and then you can sell to an exchange and it's going to be just fine.

[01:09:47] Vlad Costea: I was curious what you think about it. It seems like you don't think about it at all.

[01:09:54] John Light: Yeah, it's not. It's not on my radar, really.

[01:09:58] Vlad Costea: So what is on your radar? Where do you look for inspiration when you want to improve the product of Alpen Labs or maybe do some research?

[01:10:11] John Light: I talked to... [John was accidentally muted here for about a minute] ...technology that we can take advantage of.

[01:11:14] Vlad Costea: Sorry, sorry, sorry. Can you repeat the whole sentence because I've made a horrible mistake and I muted you instead of myself. So basically when you started saying where you look for inspiration. Sorry.

[01:11:27] John Light: Yeah, OK. Yeah. So what I said was first I just I talk to users and I see what people want to do with their Bitcoin. That is not possible to do on Bitcoin layer one today because Strata offers an almost unlimited number of possibilities of things that you can do with your Bitcoin. And then another place that I look is Ethereum. And for two reasons, one, because Ethereum is an EVM chain, it's the most popular, like widely used EVM chain and Strata is an EVM chain. So we have that in common.

[01:12:18] John Light: And also, Ethereum has a big roll up ecosystem. And I'm interested in, you know, seeing and building a big roll up ecosystem. And so I you know, I can we can like look at Ethereum and see like what is going well, what is not going well. There are definitely some lessons to learn there in terms of what to do, maybe what not to do. And we can also benefit from the fact that, you know, that ecosystem has been in development for over a decade at this point.

[01:12:51] John Light: And so we can take advantage of, you know, the modern technology that has been built for the EVM to scale the EVM, as well as like build a roll up ecosystem that is secure, user friendly and, you know, provides both users and developers a near infinite number of possibilities or options of how to build applications and create value. So those are those are some of the main places that I look for inspiration. And I also just kind of keep my ear to the ground on the research side of things.

[01:13:47] John Light: Some researchers are specific to a given ecosystem. Others are more general, just kind of, you know, cryptographer researchers or blockchain researchers or consensus researchers, whatever. And yeah, I like to follow the research to see what what new capabilities people are coming up with, what new performance improvements people are coming up with, etc.

[01:14:18] Vlad Costea: So would you say that right now Bitcoin in terms of getting smart contracts is five to 10 years behind Ethereum?

[01:14:28] John Light: It depends. I think like with BitVM2 we can, you know, we'll have like EVM trust minimized EVM smart contracts on Bitcoin like probably this year. In terms of doing it trustlessly with a native ZK verifier on Bitcoin. That's probably more like on the order of like five to 10 years away, but hopefully sooner. I can't I can't predict how long it's going to take for that to be enabled.

[01:15:09] Vlad Costea: John, I know that you worked on a hardware wallet project and also something concerning full nodes. And I was wondering, what's your best advice for users to secure their coins?

[01:15:24] John Light: Well, I never worked on a hardware wallet project. I did work on a full node project. But nonetheless, I can still speak to that question. It really depends on your situation. It's kind of a cop out answer, but like it really does depend on your situation, your living situation, your budget, your, you know, how many coins you have and are trying to secure. Like, yeah, there's just so many different factors that go into it. I would need to kind of assess that on like a case by case basis.

[01:16:02] John Light: Or maybe if you gave me an example, I could maybe, you know, Bob has so many coins and, you know, lives by himself in a first world country or whatever. You know, like I might be able to just wing it and like give an example or something.

[01:16:19] Vlad Costea: I guess whatever happened in Los Angeles over the last week proved to a lot of people that this advice about not holding the keys in your house and using metal instead of paper and all of these ideas are not crazy. This can happen to citizens of the first world, some of the wealthiest in the entire world. And it's pretty scary when you think about it. You realize that, okay, whatever setup you have, as long as you have it in your home, it's not just vulnerable to thieves or your family members or neighbors who might come into the house or whatever.

[01:17:01] Vlad Costea: It's also vulnerable to natural disaster or manmade disaster. And if you put the keys outside of your house, you also need to be careful because anyone who understands what that's about is going to steal from you. And if even if you divide it in parts that have no meaning or usefulness to people who may find them, it's still difficult for yourself. So to which lengths would you go in securing your coins?

[01:17:31] John Light: Yeah. Yeah, I mean, I think, you know, as a general maybe rule for people who are storing a significant amount of Bitcoin, I think multisig with geographically distributed backups is the gold standard. You know, that's about as far into detail as I could go, again, without knowing somebody's like situation and their means. But I think that prevents a lot of the worst kind of disasters that Bitcoin holders are likely to face, whether it's a natural disaster or robbery or whatever. Kind of an evil maid attack kind of thing.

[01:18:24] John Light: And I would certainly err on the side of making it difficult to access your coins. I think that's a feature of a good security setup. As long as you actually can access your coins with enough effort, making it more difficult is actually a good thing. Adding time delays and things like that. Those are features in the legacy financial system that we complain about. Like, oh, it takes so long for money to transfer and stuff like that. But these are actually security features that through evolution of the system over time, professionals realized like, yeah, we should make money slow.

[01:19:16] John Light: That's good for security. And I think the same applies to Bitcoin.

[01:19:24] Vlad Costea: Yeah, you've just reminded me of a video that I saw on Twitter with some kid who gambled all of his money and he lost like $10,000 in 30 seconds. Wow. And then he realized what the fuck just happened, you know? If he was using cash and actually handing $100 bills a hundred times, I guess he would realize much sooner that this is a bad idea. But for him, it was just the press of a button and he just increased the odds and increased his leverage basically by clicking a button and then realized, oh my God, I just lost a lot of money.

[01:20:04] Vlad Costea: And what you just said about making money slow. Especially when it's digital and weightless and you don't feel anything when you're transferring it makes a lot of sense. When you're spending with your debit card or credit card or whatever, you don't feel like you're spending money. But when you're handing cash and there's some effort that you're making to make the payment, it actually feels like you're doing something. In the case of Bitcoin, it's a little bit of an in-between situation because you still have to type your passphrase or something or input the receiver's address and set the fee and stuff like that.

[01:20:44] Vlad Costea: But it's scary. Anyway, I gotta plug Hodling... I gotta plug Hodling.ch.

[01:20:53] Vlad Costea: They're also a sponsor of this show and they're experts in helping you with your self-custody. They're a company in Switzerland. You go to them or you give them a call. You explain to them what kind of setup you have and they will tell you whether or not you should use multisig, what kind of hardware wallet. Where you should keep that and all sorts of advice to make sure that it's difficult for you to lose your coins. And they especially work with companies that start to add Bitcoin to their balance sheet or with whales who are very concerned about the $5 wrench attack.

[01:21:25] Vlad Costea: So Hodling.ch if you're not aware of them, check them out. And sorry for saying that you work for a hardware wallet company. It's just that the description for BitSeed is a bit vague with built hardware and free software that made it easy for anyone to run their own full Bitcoin node. I was thinking hardware, sorry.

[01:21:44] John Light: It's all right. Yeah. Yeah, BitSeed was the project and we built and sold, you know, plug and play Bitcoin full nodes. I think it was actually the first plug and play Bitcoin full node on the market.

[01:21:56] Vlad Costea: That's really cool because I think Casa gets credit for popularizing this concept of node in a box. And it was I think Chamath or what's his name?

[01:22:10] Vlad Costea: One of the guys from Silicon Valley who are wealthy and are VCs.

[01:22:16] John Light: Chamath?

[01:22:17] Vlad Costea: Yeah. Didn't he also have like a Raspberry Pi node?

[01:22:23] John Light: I actually don't know. I don't follow, I don't follow his work.

[01:22:27] Vlad Costea: Yeah. Anyway, it's quite... Right now, I think it's a pretty profitable business, especially for what's the most successful one, Umbrel. They have pretty good branding and marketing and they have that Bitcoin machine that they're selling. I think they moved past the Raspberry Pi. They have the Intel NUC.

[01:22:52] John Light: Yeah, it's been great to see the explosion really of so many different full node projects coming out since BitSeed first launched. More full nodes, making it easier for people to run full nodes and connect it to their own wallet. So they're actually using their full node to protect the privacy and security of their wallet. More of that. Love it.

[01:23:22] Vlad Costea: What kind of hardware were you using for BitSeed? This was 2015 or something?

[01:23:30] John Light: Yeah, we were using something very much like a Raspberry Pi to start with. It was just kind of an alternative single board computer. And then we eventually switched to an Intel based mini PC.

[01:23:59] Vlad Costea: I guess that's the natural progression. I see that Jameson Lopp also contributed to BitSeed on GitHub.

[01:24:07] John Light: Yeah, he was one of our first customers and early supporters.

[01:24:14] Vlad Costea: This is really cool. What was the reception like? Did people get the point of having this box in their home that is running Bitcoin Core? Or did they say, you know, we have laptops?

[01:24:29] John Light: Yeah, I mean, some people, you know, I think, whenever one of these kinds of products come out, you know, you've got some people who understand the value and are really happy about it. And other people were like, oh, I could just buy this and do it myself. And we support both viewpoints. As you said, you know, we have a GitHub. All of the instructions for running our software and stuff are open source. If you want to DIY, go for it. And you can use our software. It's free software if you like our software.

[01:25:06] John Light: But, you know, a lot of people, they just wanted a plug and play thing. And we didn't quite get to the point where it was like fully plug and play and you could connect your wallet. We were like building up to that, but didn't quite get there. But that's, for me, like, you know, the vision is like you have this box, you can plug it in, get a QR code on your browser that you can scan with your phone and like pair your wallet on your phone with your own full node and like your setup.

[01:25:40] John Light: That's it. Go. And, yeah, I mean, I think it's, you know, some people have the time, patience, expertise to be able to build their own full nodes. You know, to this day, I run like my own full node that I built by hand. I used to run a BitSeed, but eventually, like the services that I was running on it, like took up more CPU than the BitSeed itself was capable of. So I like upgraded my setup, but I know people out there who are still running BitSeeds and it works for some people's use case.

[01:26:24] John Light: And that's cool.

[01:26:26] Vlad Costea: I was going to ask you, because this is fresh news. About 12 hours ago, we had Max Keiser announcing, and he's the advisor for the president of El Salvador, and he announced that there's going to be this legislation to get a Bitcoin node in the household of every El Salvadorian. And do you see this as being bullish or does it sort of defeat the purpose of Bitcoin, which is that it's voluntary and you do it because you want to use this technology, not because some politician tells you that you should have a box in your house?

[01:27:03] John Light: Yeah, I don't, I don't, I don't believe in, I don't, I don't think it's right for governments to buy Bitcoin or buy Bitcoin nodes and put them into people's houses or anything like that.

[01:27:15] Vlad Costea: Oh, so you're not bullish on the Bitcoin reserve either?

[01:27:22] John Light: No, no. I mean, in terms of how it's going to affect the price, I'm sure it's bullish. But, you know, in terms of like, do I support it politically? No, no. I think they should just, I think they should give that money back to the people they took it from, the taxpayers. And then the taxpayers can decide if they want to buy Bitcoin or not.

[01:27:43] Vlad Costea: I think about this a lot because gold is just perfect for what governments are doing. It's hard to move around. It's physical. You can't have one tyrant stealing all the gold reserves without everyone else noticing. But in the case of Bitcoin, like, how are you going to manage the keys, right? Who's going to have access to it? You have one country, which is questionably democratic, and you have one guy who is spearheading this movement that they're buying Bitcoin. And the question is, let's assume the worst. And there's going to be a coup d'etat.

[01:28:21] Vlad Costea: There's going to be something happening. And this guy has to run away from the country unless he wants to face some sort of execution from the rival militia or something. Is he going to leave the Bitcoin reserves in the country or is he going to get them for ransom or something just to have leverage to negotiate? Or what prevents these people from just spending the coins among themselves when they leave government? And you had the entire mass of taxpayers giving you money to administrate it somehow. Administer, I think is the right verb.

[01:29:02] Vlad Costea: And then you find yourself in a situation where, first of all, you don't have any access to that. It will never belong to you. Secondly, it's being used for purposes that you did not expect when you financed this movement. So it's very weird to me, this idea that governments should own Bitcoin at all.

[01:29:26] John Light: Yeah, I mean, I don't think it's too weird. Like, it's understandable, especially if you believe Bitcoin is the next evolution of money and such, like, money is a big part of the government, whether it's because governments create money or because governments need money to fund its services and so on. So I think, from that perspective, it's only natural that governments somehow begin acquiring Bitcoin. And of course, if you think Bitcoin is going to go up in value, like, governments, they have their reserves, they like, they like to hold things that go up in value, just like anybody else.

[01:30:05] John Light: So from that perspective, it's like a natural, I think, evolution of things. But again, like politically, I don't, I don't think that government should be involved in Bitcoin, or anything else for that matter. Like, I think they, I think they should leave it in the hands of the free market.

[01:30:24] Vlad Costea: If Bitcoin development becomes ossified, and we just have some basic maintainers who are going to port Bitcoin Core to new operating systems or something, what's your backup plan? Like, we're not going to have any major breakthroughs in terms of scalability or privacy. The way that we look at Bitcoin today is most likely what we're going to have in the future. Let's imagine this scenario. What's next? What are we going to do?

[01:30:55] John Light: I think that the incentives of the system will lead people to want to expand Bitcoin's capabilities to expand the number of users that can hold Bitcoin, because those things are going to make Bitcoin ultimately more valuable. And so I don't see an outcome, actually, where Bitcoin doesn't become more expressive, where Bitcoin doesn't enable things like the ZK verifier, more expressivity, more scalability, because these things are good for Bitcoin, and things that are good for Bitcoin make Bitcoin more valuable, which, you know, I think is good for everybody that's holding Bitcoin.

[01:31:47] John Light: So I think it's just a matter of education and demonstrating, proving as well as we can that the changes that we are proposing are actually safe and are actually good for Bitcoin, and then they will happen. They will happen on the time scale, you know, a Bitcoin time scale, but they will happen. If by some, you know, crazy scenario, whatever, like people just can't be convinced, and we do end up ossifying, then I don't know, I guess we have to live with BitVM2 and altcoins.

[01:32:31] Vlad Costea: Yeah, I think about this a lot. And there's also the issue of what if we build something really great, but there's not going to be any significant amount of users that are going to support it. For example, the Lightning network, right? Whether or not you like it's around and it has some users, but it hasn't seen any significant growth in years. It's still at around the same amount of liquidity. The amount of channels hasn't really increased. If anything, it decreased because some lightning service providers decided to make everything more efficient and have fewer but larger channels.

[01:33:14] Vlad Costea: And it doesn't really seem to get that amount of traction that was expected from it. Many investors were thinking, oh, this is going to be the retail or alternative to Visa or something because it's faster or whatever. And then they changed the narrative and they said, you know, it's better fitted for business to business. Yeah. And there's also this problem about ZK roll-ups, you know, you build them, they're really great, but then you don't get the users to come and actually give them value and give them utility.

[01:33:48] John Light: Yeah. Yeah. This is what product people, you know, people who work in product management, this is part of their job is to find out what do people actually want? What are people actually going to buy or use? And, you know, that requires like research and not just like, you know, behind the screen in your office, but like going out and talking to users in the real world and finding out, like, what are the real problems that people have? And what are, you know, are they willing to like use or pay for a solution and, you know, developing a product that provides an adequate solution to the problem?

[01:34:37] John Light: And I think Bitcoin's challenge today is just that, like, it doesn't enable that many solutions or like the solutions it does enable are relatively, you know, cumbersome, just trying to work around all of the limitations of Bitcoin script. And so, like, it does a few things, like, pretty well. And then it does a lot of things, like, not very well. And I think the goal of, for me, like getting a ZK verifier on Bitcoin is enabling people to try many more different kinds of solutions to the kinds of problems that people have using peer to peer electronic cash.

[01:35:24] John Light: And just, you know, letting the process of evolution take place as people try many different things, lots of things are going to fail, just like in the business world, you know, nine out of 10 businesses that start fail within the first couple of years. But, you know, the ones that succeed have, you know, have a good chance at, you know, changing, significantly improving the lives of the business owner, their customers. And, you know, in some in some cases, you know, small number of cases, they change the world.

[01:36:05] John Light: And so, you know, I want to I want to see that for Bitcoin.

[01:36:11] Vlad Costea: It's very nice to be optimistic. And it's also nice that there's a lot of money that goes into funding projects. What I see that's missing is the enthusiasm of the users, because there are a lot of layer twos right now getting built. But I don't see any organic, how should I put it, like some sort of anticipation from users and say, Oh, I can't wait for this to exist. There's Ark, there's the ZK rollups, there's drivechains, all of them are competing to enter this market, and to provide utility to the users.

[01:36:46] Vlad Costea: But all I see is just the same people being cheerleaders of their tribe, you know, but I don't see anything as big as the lightning network in terms of anticipation. For the lightning network, there was a lot of hype, there was a lot of desire to have that it was like the protocol that was supposed to put an end to the need for blockchains. And it ended up very disappointing, or disappointingly, I don't know how to describe it.

[01:37:20] John Light: Well, I think that, yeah, well, I think, like, one way that it could turn out is that, you know, somebody comes up with something that does like energize the existing Bitcoin community and the Bitcoin community, like it's behind it and is, you know, really excited about it. And that becomes the next hot thing. I mean, backtracking a little bit, like, for what it's worth, like, I think lightning is an incredible achievement. It is the only trust minimized L2 that operates at scale right now. And I mean, like, in the world, on any chain.

[01:38:02] John Light: And so, like, that's, that's like a huge achievement. I use lightning on a regular basis. And, you know, I haven't had a failed payment in a very long time. And so, like, I think lightning itself, like, maybe like doesn't get as much credit as it deserves for as well as it is working. But it does have challenges of its own UX challenges and scaling challenges that I think ZK can help with. But additionally, I think, you know, again, I think we could see developers come up with another kind of scaling solution or privacy solution or whatever that, you know, gets organic traction amongst Bitcoiners and, you know, gets that organic, like, community of existing Bitcoiners rallying around it and excited.

[01:38:51] John Light: But I think another outcome is that, you know, some developer comes up with an idea for something, just like builds it, launches this network kind of, you know, relatively quietly, and then just starts onboarding people, like new people, you know, not people from the existing Bitcoin community, but other people out there in the world who have a problem that needs to be solved, you know, with money or savings or whatever. And, you know, this developer has, you know, used the new capabilities of ZK to build a solution, build a product that solves that problem, and then goes to market with that.

[01:39:36] John Light: Completely routes around the existing, you know, Bitcoin community in terms of their go-to-market strategy, like, because maybe, you know, the existing Bitcoin community just doesn't have the same problem or, you know, just for whatever reason, like isn't the right audience for that particular product. I think that's something that could happen in that world. It's like, yeah, just having a whole new wave of like Bitcoiners who maybe don't even realize that they're Bitcoiners because they're using a product that's like built on Bitcoin, but it doesn't really put the tech or maybe even Bitcoin like front and center.

[01:40:24] John Light: It's just like you have a problem, we solve your problem, and, you know, it kind of like goes viral that way.

[01:40:32] Vlad Costea: The way that I remember Bitcoin is that it was a bit more technocratic in the sense that you had these developers who had a good reputation and users were looking up to their opinion on stuff. But it seems to me that now it's more tribal than it is technocratic. I don't see as much conversation about technical merits of stuff. It's just mostly who proposes it. For example, OP_CAT, it's a very simple idea about concatenating two different inputs of data and putting them together to form something else.

[01:41:09] Vlad Costea: The conversation is more about the Taproot Wizards, right? And the fact that they're trying something which comes from Ethereum, which is this villainous and vilified chain. Saifedean called it the mother from which all the shitcoins, like the mother asshole or something from which all the shitcoins are coming. And it seems like there's a hatred for anything that comes from that community. And I don't know how to mitigate this. I think we need some sort of change in culture in the way that we perceive honest cryptographic and computer science research as opposed to just a money grab attempt.

[01:41:50] John Light: Yeah, I mean, I think it's true of any kind of technology that, you know, some people are like the tech enthusiasts and they get into the weeds on the technical details and then other people are just like, you know, they're just happy that the technology exists and they use it and they might have different influencers or whatever that they'll follow to try new products or what have you, but don't get really into the weeds of the tech. And like, that's probably fine. I mean, I wish people would like more people would get involved in the technical discussions and they really like understand and discuss these things.

[01:42:33] John Light: But, you know, it's not for everybody.

[01:42:38] Vlad Costea: Anyway, you sent me a message. You said you need to go. I don't want to take more of your time. Final question, John Light. How can people follow you and keep up with your work?

[01:42:48] John Light: Well, I have a personal website at lightco.in, that's L-I-G-H-T-C-O dot I-N, where I post about Bitcoin and other things that I'm interested in. I also have a Twitter account at lightcoin, L-I-G-H-T-C-O-I-N. I work on Strata. You can learn about Strata at stratabtc.org. And the company I work for is called Alpen Labs. And we have a website at alpenlabs.io if you want to see what we're up to.

[01:43:25] Vlad Costea: Okay, thank you very much, John. And thanks to all the sponsors. I'll mention them again. LayerTwo Labs, SideShift, Citrea, NoOnes and Hodling. I'll see you in the next one. See ya.