บทถอดความฉบับเต็มของ Connecting Cosmos and Ethereum with Gravity Bridge

sleeves and visit leo-lang.org to start building that's leo-lang.org. Aleo will also be participating in ZPrize a competition, accelerating the future of zero knowledge cryptography, visit zprize.io for more information. So thank you again, Aleo. Now here is Anna's interview with Gravity Bridge. Anna Rose (03:16): Today. I'm catching up with Deborah Simipier and, Justin Kilpatrick co-founders of Althea and the team working on Gravity Bridge. Welcome to the show. Deborah Simipier (03:24): Thanks so much for having us. We're really delighted to be here. Justin Kilpatrick (03:27): Yeah, it's nice to be here. Anna Rose (03:28): Deborah. We first met when we did this event together, the zero knowledge validator did an event called Cosmos in privacy, and you were one of the speakers and I realized then that, you know, you were presenting sort of the finished version of Gravity Bridge. And I, I realized I don't actually know that much of the backstory of this project. And so this is kind of what inspired this episode. And I think that might be an interesting place to start. So what is Althea exactly? What is that company? Deborah Simipier (03:56): This story of Althea is the story and Genesis of, of Gravity, which is quite interesting, right? So Althea is a distributed networking platform that allows for many different entities to own pieces of infrastructure of the internet and a service provider to provide service to the internet and get paid a revenue share for doing so and so at its core, it's a routing and, and building platform that settles onto a blockchain. So we work with one foot very much in the real world of, you know, providing internet service, especially in challenging environments, like very rural places or urban places where they're the there are people under connected because they don't have access to banking and things like that. So when we're working in the, in the real space, we we use stable coins, right. So folks can access the internet and load up their routers with like regular something they're familiar with. Deborah Simipier (04:50): Right. one of the main kind of UX ways that we look at how people interact with their, their devices is that we, we don't necessarily look at it by how had that educational lift right. Of having to understand how everything works. Right. They should just be able to use it. And then everything kind of works behind the scenes. And so stable currencies are a really big part of that. So the bridge was very important because we wanted to be able to interact with the Cosmos blockchain ecosystem where Althea lives, but still use Ethereum based stable coins that are readily available with Fiat on-ramps. So hence we needed an interoperable bridge. Got it. And yeah, so I mean, and Justin really like what I introduced Justin here as the co-founder and also the kind of, you know, designer and had built the majority of what is Gravity Bridge to, so he could perhaps give a more technical bend to that. But

from a, Hey, I've got a fire station that needs to be able to get internet in a rural place in Oregon, we need a bridge and that's, that's where we ended up sort of building this, this infrastructure. Anna Rose (05:57): Cool. Yeah. Justin, you co-founded Althea from that beginning point or did you join later for the Gravity Bridge part? Justin Kilpatrick (06:04): No. So I actually started on Althea first. So interestingly enough, the story of Althea is that there were three, three original founders that had all sort of worked on the idea of, you know, blockchain, internet service, and they'd all sort of poked at it. So I think I have the first ever like blog post, you know, like serious implementation attempt. That was me in early college. Didn't work out very well. Cuz I wasn't technically capable at the time to do it. So I graduated college and I thought for sure somebody would pick it up, you know, there would definitely be a blockchain internet service by the time I graduated college, my opportunity was gonna sail on by. But you know, I graduate you know, I get a nice job at red hat. I'm doing performance engineering and you know, I'm, I'm just getting kind of bored and I decide, well, okay, let's, let's check in on this idea again. And, and there really hadn't been any progress and I was disappointed. I'm like, this is such a great idea what happened. And unbeknownst to me, Deborah and Johan the third co-founder of Althea had both been, you know, sort of looking for the same thing and were also disappointed that it didn't exist. So I started the development of what would become Althea just cuz I wanted to see it exist. And that is where, you know, Johan found me and said, okay, well let's sort of make this less of a fun open source project and more of a cryptocurrency startup. And then Deborah found us and said, Hey, I've got a town that needs the internet. So I, I quit my job at red hat and I worked probably too many hours to say, and I shipped out the first demo router to Deborah about three weeks later. Anna Rose (07:47): Cool. Deborah Simipier (07:48): I still have that router router number zero. So it's probably on my shelf providing the very first you know, blockchain internet service. So a little tiny town in Oregon and it's grown since then, but you know, it was a, it was a really exciting moment when I first got that router number zero. Anna Rose (08:05): Can you give me a bit of a sense? I wanna, I think for right now I wanna focus on Althea and a general core idea of sort of the ISPs and this private band. Like what exactly, can you maybe paint a picture of like what would it be used for actually, and just before that, just a question like did blockchain was blockchain in its inception or did that come later? Justin Kilpatrick (08:26): So blockchain was definitely in the inception. Okay. Anna Rose (08:28): Okay. Justin Kilpatrick (08:29): And the idea is to build a more efficient way to buy and sell internet. So right now

let's say you own a mile of fiber it's not useful. How would you sell that mile of fiber to somebody? And the answer is that you can't really Anna Rose (08:45): One thing mile of fiber. When you say that, what does that mean? Is that the wires? Justin Kilpatrick (08:50): Yes, yes. Yes. So like, let's say you have a mile or 10 miles or a hundred miles of fiber optic cable, you know, it's buried maybe by the side of the road, maybe across people's property, but anyways, you have a high bandwidth capacity link between two places. And the problem right now is if there's no way for you to sell it and us as internet customers, we have, you know, maybe several different lines to our home. But we can only buy from one provider. And we're sort of locked into that one provider. So isn't it kind of ridiculous that you can have two different internet wires to your house. You know, let's say one is, one is AT&T and one is Time Warner or you know, some other big monolithic provider. Well they both paid have somebody come out and run a wire to your house. So you're paying for twice the infrastructure. Yeah. Then you can use, and then if time Warner goes down, it's not like you can just switch to the other one. You know, you, you're stuck, you know, you have to call them, sign up, have somebody come out the, come out to the door. So there's sort of two sides to this problem. As a customer, you are locked in for no good reason. You have this infrastructure to your home that you can't use that you're paying for twice because no matter which provider you're subscribed to, you're paying for the wire they installed. And then somebody who maybe has the asset that you need that has that buried high bandwidth line to let's say the front of your neighborhood, there is no way in the world for you to buy that from them. That's ridiculous. The metaphor I really like to use is that it's like if a grocery store insisted that they'll only sell you bananas on a subscription and that subscription is for unlimited bananas. And I tell you how great and unlimited bananas are, but you can only ever get them from this one store. And then you really need to wonder like which grocery store is gonna have the best bananas. Is it really worth paying seventy bucks a month for, should I just not? And this is where you get a lot of underserved people who don't purchase home internet because they have to pay a high entry price and they have to really evaluate like, what's it worth? And in this comparison it quickly becomes ridiculous. Why don't you go into the store and just buy a single piece of fruit? Why is that not possible? So this is what Althea makes possible. Anna Rose (10:59): But you mentioned sort of like someone owning this fiber, it's not like an individual, I'm assuming these are companies that have installed these fiber optics under the ground, or are there like individual independent fiber layers? I don't know if that's what you call them. Deborah Simipier (11:15): Yeah. I

think that's, what's so exciting is that you do have new entrance into the market because of what Althea makes possible. And we've actually seen this to be the case where independent investors are buying, you know, some we have a for example, a network in Illinois it's 10 miles a fiber to the home and that's owned and separately by someone who's investing in that, that particular piece of fiber optic cable. And then there's a service provider that's decoupled. So a decouples the service layer allows anyone to be kind of be the network operator. It's a local company called Silo communications. That's worked in that area for a long time, has the trust of that community who is installing the network and maintaining it. And they get a, you know, a daily fee automatically transparently on the blockchain. And then the, the investor who put money into that fiber optic cable is also getting a revenue share of that transparently programmatically automatically on the blockchain. And it's these really agile and flexible configurations that the protocol and blockchain make possible. Anna Rose (12:18): And this is, I guess, built with the Cosmos SDK. I always never, I never know if you're supposed to say on or with? Do you know? Justin Kilpatrick (12:24): That's a good question. Anna Rose (12:29): Let's go with, with the Cosmos SDK, I guess. Justin Kilpatrick (12:32): So for a lot of blockchain projects, they start with the blockchain and then move to sort of the application they want to build. Cuz obviously they want to like front load issuing a token and sort of the, like the like funding part of everything for Althea. Like I was describing it, it started as sort of a passion project. You know, we wanted this to exist. So we did a developed the home software. So the actual Althea routers that people have in their home that are running our software, that we flash with our custom operating system et cetera. We developed that all first and we got that running. And now we are looking to move to Cosmos SDK from xDAI, which we selected as a stop gap for low fees and native tokens. So there's two enormous components, obviously developing a in-home wifi router is not a small product to build. And it much less integrating it with blockchain and all of and making it work reliably enough for people to use as their home internet. So this is all a big challenge and that's a challenge we saw first. So we have real customers. We have there are Althea networks currently all over North America and a couple international that are, that are making revenue that have real users that are operating in a very literal sense. You really can't fake selling somebody bandwidth, you know, like what are you gonna do? Give them fake Netflix anyways. So now we are looking to move to Cosmos SDK, which comes back to Gravity bridge. We needed to build our own bridge cuz there was no way to get DAI or any other Ethereum stable coin for that matter into a Cosmos SDK based Althea blockchain.

Anna Rose (14:07): Got it. And xDAI, we're talking now renamed, I guess Gnosis Chain. Justin Kilpatrick (14:12): Gnosis chain. Yes. Anna Rose (14:14): But what operates today is still on Gnosis chain then? Justin Kilpatrick (14:18): Yeah. What operates today is currently on Gnosis chain and we are looking to launch and move over to the Althea blockchain. Obviously we had to get Gravity Bridge up first. Okay. Which we got up just recently. So now we're taking a bit of a breather, stabilizing Gravity Bridge and getting ready for that next sprint. Anna Rose (14:34): Cool. Deborah Simipier (14:34): Just to kind of roadmap that a bit. We're looking to launch the Althea blockchain here in the next few months. So if there are folks that wanna come on board and be validators or participate in any of the mini rules in Althea, there's like an opportunity here over the next several months to, you know, to, to join that community and, and help those networks grow. Anna Rose (14:52): Where does the decision come to move from Gnosis chain to a Cosmos SDK chain? Because I guess if you did it on, on xDAI previously in Gnosis chain now it's, it's solidity smart contracts. I'm assuming that like allows you to use this. So to make a whole new chain. Yeah. I'm just curious. Why, why, why the shift? Deborah Simipier (15:11): Well, we are, I haven't checked in a while, but we were like over 71 or 72% of the micro transaction traffic of xDAI already. We are on a platform that is not going to be able to scale with our enormous growth that we're projecting over the coming year. We have several large urban areas that are coming on board. And so really it's just a matter of this, this chain not being able to scale to to Althea, you know, needs as a worldwide service provider for telecom. Justin Kilpatrick (15:41): So EVM based chains are designed as financial blockchains. So the person who pays the highest fee should be the one who gets in first and this is not appropriate for a telecom platform where we want predictability above all else. So we don't have the sort of low level control over Gnosis chain or any EVM chain. That's required to guarantee that, you know, Hey, it doesn't matter what happens, how much load there is, you know, whenever it starts streaming the super bowl, this thing's gonna stay up. Everything will work correctly. Everybody will remain in consensus and there will be not a stutter, a glitch or any sort of problem. So we need that low level control and that sort of sovereign chain to achieve that. Okay. you know, so we've worked a long time and very hard to develop and stabilize this software and get it to the point where it's extremely reliable and can run across, you know, hundreds or thousands of different routers remain in consensus, do things that even traditional networking software provided by very large organizations, you know, can't compete on, but now the limit to our reliability is the blockchain platform or on, you know we can't make Gnosis chain work better for our needs. Justin Kilpatrick (16:58): And that doesn't mean that it's not working great for their needs. But you know, that's what we mean when we say, as we scale up we need to move to the Althea blockchain so that we have sort of the reliability and also to expand into other applications in the telecom space that will better help people, you know, construct infrastructure and maintain infrastructure, et cetera. Anna Rose (17:22): Will you be building this Althea chain as an EVM compatible one? So you could just migrate the contracts over or are you like, is it built for this use case with like I, yeah, I'm just kind of curious how, what you've built today can actually live on this new chain. Justin Kilpatrick (17:39): So Althea actually developed the first sort of native rust client for Cosmos SDK chains, which we have dramatically updated for use in Gravity Bridge. And now that same code is going to go onto our routers and allow them to talk to the chain cause it's actually micropayments rather than the need for any specific sort of EVM contract. Okay. so this is relatively easier to port, but we have always been focused on keeping our technology, you know, compact, simple and swappable. So we're going to swap from sending native EVM transactions to native Cosmos SDK transactions. As a bit of a detour, you know, we had to write our own Ethereum encoding library as well. Oh wow. And the reason for that was because these, the processors and the routers were not supported by anything that encoded Ethereum transactions when we first started development. So we had to actually write the software to encode the Ethereum transactions ourselves. So we're sort of sort of familiar due to our requirements. You know, they're, they're very strange, you know, these little boxes out in the middle of nowhere being rebooted overheating, stuck in a cabinet terrible network connections doing weird things all the time existing tooling doesn't often work for us. So we're sort of used to having to build things from the ground up Deborah Simipier (18:57): Just to follow onto Justin's thought. I mean, I, it has been very fascinating and rewarding journey to like work with blockchain, which is such a new and evolving ecosystem into you. The, you know, day to day lives of like, like I said, whether it's a fire station or we're in a mosque in Nigeria, or, you know, just, you know, people's houses in the country or in an urban environment where they're, you know, we're looking at, you know, 3-400 megabits per sock and and all of that sort of day to day demanding 99.9% uptime is just, it's really read led to, I think, a very hard end system and very practical system. And to Justin's point also, you know, that's why we focus on that simplicity and I mean, literally testing and fraud. Anna Rose (19:45): Cool. I wanna move on now to, or very soon to the Gravity Bridge and bridges in general, but I just have one last question for Althea as

a concept. Like, is there ever a use case for situations in like conflict zones, obviously right now, like a lot of people are thinking about technology for that kind of environment or is, is this sort of, it would be kind of complicated to lay the foundations like the, the fiber needs to be there. It needs to be accessible or yeah. Is that even something that's that's being thought about in this project? Deborah Simipier (20:17): Yeah, I, so a lot of the reasons why we do this are to protect the core freedoms of the internet. And we think that the, the best way to do that is with decentralized ownership, right? And a distributed type of network. I think a lot of our later work that we've been working on with an LTE core embedded into the router also empowers some very interesting sort of, you know, agile dynamics as well, where you can literally have like a small cell anywhere, right. And those SIM cards can then be, you know, activated to be on that network and, and deployed in a really rapid way. So I think there are difficulties with communications without having some of those foundations, you know, laid beforehand, right. You know, everything is all communications are gonna come back to an IX or data center at some point, but I think we're evolving to get to that point. And I think there's a lot of sort of, you know, agileness and resiliency that comes with decentralized ownership. Anna Rose (21:15): So let's now jump into the Gravity Bridge. I actually have over the next few months, this plan to invite a number of bridge teams on, I think you are the first of this not official series, but what series. And I think it's good for us to explore and maybe redefine for our listeners what bridging is exactly what it looks like. Maybe what's out there. I mean, maybe some of the techniques. So before we go into specifically the Gravity Bridge, let's do sort of a high level on bridges. And then we can look at the bridge that you guys built. So let's talk about bridges. What do you think people need to understand, to understand a bridge? What are the concepts that might help our listeners like get into this topic? Justin Kilpatrick (21:57): So across blockchain bridge is an application that locks up an asset on one side and mints a like representation. So, so it's sort of a synthetic representation of that asset on the other side. So presumably both sides are programmable blockchains, but that it's not necessarily required to achieve the locking and unlocking that we're talking about here. So the key thing to understand about cross chain bridges is that there are a couple of key questions when you're thinking about bridges and that is who holds the locked assets on one side or the other side, how do you know that you can trust them? What happens if they were to defect from the protocol and do something that they are not allowed to do? And what guarantees do you have that the code you we're seeing will stay the same. And these are really the key sort of questions around bridges and bridge security. Justin Kilpatrick (22:57): Cause I will highlight this again and again when you bridge Ethereum, when you bridge some other asset, you are not receiving the same thing. On the other side, it's a synthetic token that represents the locked token that was locked on the native chain, the native chain being the blockchain, where the asset originated. So from here, let's move on to sort of the designs of bridges. There are various kinds of bridges, depending on the constraints between the, for example, you can have a light client bridge where the bridge interprets the actual consensus state from the other blockchain and takes actions based on that interpreted consensus state. This is the most secure type of bridge. But for example, you can't use it with Ethereum because Ethereum is still proof of work. And the lack of finality means that you can't actually be sure that any presented like chain header or in this case, a block is the final version, but IBC is a light client based bridge. Justin Kilpatrick (24:04): So this is what happens when you have an IBC channel, is that it actually interprets the state of the other Cosmos chain and it's updated and moved across. And this provides a really high level of security, but also they're difficult to develop and often quite specific, obviously right now, IBC only goes from Cosmos blockchain to Cosmos blockchain because it's difficult to implement and also somewhat difficult to work with because you have to find the right cryptographic information to present to the other side. Now there's also simple multisig bridges, and this is actually the plurality of all bridges right now. And these are bridges where you you really just have a multisig on like the Ethereum side. They're most common on Ethereum once again, because proof of work is a big constraint, makes it hard to build a bridge that is extremely secure hopefully, and very hopefully Ethereum will have finality and proof of stake soon, and we'll be able to solve some of these problems and provide, you know, much better guarantees. So for a multisig bridge, it's just 4 or 5, 10, 16 arbitrary number of people who hold the assets on the Ethereum side and perform the actions of a bridge by minting assets on the other side, and unlocking them on that side and Gravity Bridge being an Ethereum to Cosmos bridge. Anna Rose (25:25): Is it kind of both, are you doing like IBC on one side light client on like? Justin Kilpatrick (25:31): It's a little bit complicated, so, Anna Rose (25:34): Okay. Justin Kilpatrick (25:34): Gravity is sort of a hybrid design. So we wanted to achieve the same security as IBC but we wanted to do it on Ethereum. And I just said, as long as Ethereum, still proof of work, this is extremely difficult. So what we did is that we designed a very specific, very lightweight sort of light client for the validator set Anna Rose (25:57): On the Cosmo side, I guess Justin Kilpatrick

(25:58): Yes, for the validator set on the Cosmo side. So the validator set on the Cosmo side is represented in the Gravity Bridge on Ethereum and it executes a weighted vote of the validator based on their signatures. So it essentially provides the same level of security that a traditional tendermint lite client would in terms of operations. Unfortunately, once again, cuz of proof of work, it's not as provable as IBC. Otherwise, if it was as provable as IBC see, we would've just implemented IBC for Ethereum. And then when it comes to the other direction you know, so we just described how stuff gets moved from Gravity Bridge to Ethereum. Now we have the other direction for Ethereum to Gravity Bridge. Every Gravity Bridge validator runs a light client or a full node for the Ethereum blockchain that they then use to observe the state of the Ethereum blockchain and make claims about it. So you'll notice this isn't a header proof. They're not doing anything crypto. Well, they are doing cryptographic operations, but that's in the Ethereum note. So this, this let us really separate out the complexity and say, well, each validator, they just look at the actual state of Ethereum and then they say what they think. Well, they say what they observe as the current state of Ethereum. So this is how Gravity Bridge provides the highest level of security currently possible with Ethereum. Anna Rose (27:22): Wow. What you've just shared though, you've shared from Gravity Bridge to Ethereum, from Ethereum to Gravity Bridge, but where does it connect to the hub or something else? Like, does it have to then use IBC? And I guess there's no multisig here, right? You're, you're running an Ethereum full node on Gravity Bridge in a way, or like the are running full nodes. So they're not, they're not doing multisig. That's the one thing I, I don't hear in your design. Justin Kilpatrick (27:50): So on the Ethereum side, it is looking at the full votes of the validator set. Okay. So that means everybody is submitting signatures. It's performing the like weighted vote calculation. So this is much closer to a lite client than a multisig cause normally the, the defining factor of a multisig is that it's not automatically rotated. The defining factor of validator set is that it is automatically rotated. Got it. So the validator set on Gravity Bridge, as it changes, produces an update that is then brought over to Ethereum that updates the validator set on Ethereum Anna Rose (28:23): And the validator set on Ethereum is made it's in smart contracts. I'm assuming? Justin Kilpatrick (28:29): It's yes is a smart contract. Anna Rose (28:29): Okay. So smart contracts have been deployed on the Ethereum side. Are there two different validators sets or is it the same validators? Justin Kilpatrick (28:35): It's the same validators? Now they can separate a little bit because we can't get a transaction into, into Ethereum instantaneously. And in fact, a lot of the complexity around Gravity Bridge is how to optimize it so that we can have 200 validators in the Gravity Bridge contract. And in fact we spent a long time on performance optimizations for the Gravity Bridge Ethereum contract that make it more efficient, verifying the signatures and votes of a 200 member validator set. Then your average 10 member multisig. Anna Rose (29:08): And were there any tools like DAO tools that could help you here? And I know it's sort of a different part of the stack, but I'm just wondering, like, could you like for the voting you did, you have to fully develop that, is that completely bespoke? Justin Kilpatrick (29:22): That is completely bespoke mostly so that we can integrate all of these optimizations, for example we have storage optimizations that reduce the cost of cost of storing the entire validator site. Even as it grows very large, we have signature checking optimizations that reduce the number of signatures we have to check and say, Hey, you know we're only going to check 66% of all signatures sorted from highest to lowest power. Cause after that, it doesn't matter, right. So, you know, you have all of these little optimizations and they build and one on top of the other to achieve a performance, which is really pretty incredible. When compared to what you get out of like a normal multisig or even other bridges Anna Rose (30:04): The work that you did on that side on the Ethereum side is can it be used by other projects or other even like maybe other concepts or is it, would it only be useful for bridge stuff or like working with the validators that kind of off the chain? Justin Kilpatrick (30:19): It would be useful for any application in which you wanted to mirror a proof of stake validator set on Ethereum. To keep Gravity Bridge simple and very robust. We sort of reduced the design scope as much as possible, made it compact, easy to use easy to understand this has resulted in Cosmos SDK chains that use the, that use Gravity Bridge quickly becoming the most common type of Ethereum bridge on bridge on Cosmos. There are obviously several different Ethereum bridge implementations for Cosmos at this point. But a plurality of those are now Gravity Bridge based because of how simple and easily reusable it is. Anna Rose (30:56): Interesting. Okay. So I think we've explored the Ethereum side and I sort of add, I put the question in, but then didn't pursue it. So what happens on the Cosmo side? Like right now, all I know that is that you can bridge from Ethereum to Gravity Bridge, which also is Gravity Bridge a blockchain or is it a bridge? Justin Kilpatrick (31:14): It is, it is a blockchain that runs the bridge. Anna Rose (31:17): Okay. Different from Althea. So it's, it's a, it's not what we had talked about earlier with like the Althea moving to Cosmos SDK. This is a unique in instantiation Justin Kilpatrick (31:27): Gravity bridge is its own chain. Okay. So once you're on Gravity Bridge, you can use, IBC to get wherever

you need to go. So this is, this is wherever else you need to go in the, the Cosmos SDK ecosystem or the IBC ecosystem. Anna Rose (31:40): That's maybe the question is, would you, would you kind of of do a hop? So you basically, like if you're moving tokens, you're on one side, interacting with Ethereum smart contracts, somehow locking those tokens and then they move over into the Gravity Bridge, Cosmos chain live there as a synthetic, and then they'd go over IBC and be created on a new chain as a new synthetic. Justin Kilpatrick (32:04): Yes. That is how you use Gravity Bridge. And that's how mini chains already are using Gravity Bridge right now. So we are working on simplifying the process where you send a message on Ethereum and the IBC tokens, just show up on the destination chain. And that'll be out by the end of this month. Anna Rose (32:21): You kind of skip that middle step. I was gonna ask if you're supposed to do anything in the middle step, like does, does one have to manually push it through right now if they wanna use it or, Justin Kilpatrick (32:32): Yeah. So right now the existing bridge, so the existing user interface is for the bridge, you know, they open metamask and they say, okay, submit your Ethereum transaction. Then they open Kepler and they say, okay, submit your Gravity Bridge, IBC transaction. And then they're like, okay, you're on destination chain, let's say persistence. And you can do what you want to do there. So we're sort of kicking out that middle step. You'll just have to use metamask and you'll make it make it to destination. Deborah Simipier (32:59): Can I talk a little bit about why like some of the, like the business reasons and kind of the way that we look at Gravity Bridges, blockchains usefulness, is that okay to Anna Rose (33:07): Go for it. Deborah Simipier (33:08): So you know, Justin's just sort of described a bit of the technical, you know, two hop process that we're gonna be obfuscating with a forwarding module that sort of seamlessly takes that transaction and then forwards along for IBC. So that the UX for the end user is very simple, right? It's just one click send to one of the dexxes or other blockchains that I wanna use it in Cosmos. And I think that really speaks to, you know, this, the idea of Gravity Bridge as this infrastructure layer, right? Some plumbing it's an aqueduct or a sewer, something that's, that's useful in the Cosmos ecosystem to send transactions in a neutral way. Making front ends for Gravity Bridge is a permissionless. Anyone can do that. And we've actually written some really great documentation on that and sort of hope to move that into kind of like a Gravity Bridge API, a for anybody that wants to any, any blockchain that wants to interact with the Gravity Bridge and, and have their users interact with an easy frontend that they build. And then on the other side, it's just an IBC connection that anyone can connect, you know, any blockchain can connect to permissionlessly, right? So it's just this kind of plumbing. You can connect up to use a frontend of your design or one that already exists. And then you have this sort of forwarding module that just sort of sends it directly to your chain. So you have somebody like Althea that wants to use it for stable coins, or you have maybe something like a cost as well. Maybe you wanna pay for, you know, decentralized compute with USDC. And that's what Gravity Bridge makes possible in, in this kind of like infrastructure layer. Anna Rose (34:43): I have sort of a side question, which is about the stable coins, like right now. I mean, the use case, the initial use case is this needing stable coins on a Cosmos based chain, but why not have native Cosmos stable coins? Like, and I, and I feel like that is happening somehow, but yeah. What, why was the decision taken to go from Ethereum stable coin to a, a Cosmos chain? Deborah Simipier (35:09): So we can also get a little bit into also some really interesting things you can do with arbitrary logic and, you know, talking to the Ethereum blockchain for, you know, different reasons that you might wanna do as well. But I also think that it, it speaks to the resiliency of being able to operate with Ethereum, right? There's many different stable coins with many different sort of, you know, functions or more use on, you know, on an international scale. On the Ethereum side, the OnRamps to fiats are much more robust over there. So we're not relying on a single use case. And I think also it speaks to sort of the neutrality and permissionless and why we think that's a resilient use case too. Right? So if anybody can make a frontend and use anything on the Ethereum system, it's very resilient to having one stable coin or one coin or something have have problems. Then you can simply move to another one or one frontend has a censorship attack. Then you can move to a different front end. And that's, you know, this is what you see in our design with Althea. It's this really open interoperable neutral platform. And it's the same with how we think about Gravity Bridge too. Anna Rose (36:15): Got it. In doing research for Gravity Bridge, another project called Gravity dex comes up sometimes. Is there any relationship between these two or projects or is it just happening you happen to have a naming collision? Deborah Simipier (36:28): Yeah, I, I, well, you know, they kind of came about about the same time and so they were both kind of two links for the Cosmos ecosystem that kind of took that Gravity name. So I, I think, you know, they, they really speak to the alignment in the Cosmos ecosystem with the Gravity Bridge blockchain. We worked very closely with the interchange foundation with informal systems who did the, one of the audits. And a lot of these key Cosmos entities were part of shaping the design and the use case in is for Gravity, right? So Atom is one of the first blockchains that now connect to the Gravity Bridge.

So if you wanna send Atoms across the Gravity Bridge, you can use them on the Ethereum ecosystem and indexes like, you know, UniSwap or however you would wanna use them in Ethereum DeFi. Right. So this was also one of the main use cases as well. So I think the Gravity name just essentially sort of speaks to that alignment that we have in the Cosmos ecosystem. Anna Rose (37:22): Cool. Does Sommelier Zaki's project Sommelier, is there some connection there as well? Cause I know he had mentioned that he had like been working with you guys at some point, but are they using the, the Gravity Bridge or they using like a variation of it or how does that work? Deborah Simipier (37:38): Yeah, so we, we work together with Zaki in the early part of that project specifically on their, on their Gravity Bridge module. And I'm gonna let Justin kind of talk a little bit about what some of the cool things that, you know, Gravity Bridge's bespoke module can do on the Ethereum ecosystem, which I think is kind of neat, but but yeah, we've, we've long supported many of these sort of you know, forks of bespoke instances of Gravity that these different blockchains are using just in, in really specific types of ways. Right? Justin Kilpatrick (38:07): Yeah. So I think the best way to do this explanation is for me to break out like a genealogy tree of Gravity Bridge forks cause the fundamental design of Gravity was focused on simplicity and there are a lot of different, different Cosmos SDK chains that want a bridge that does exactly what they need. And of course they pick up Gravity cuz it's by far the easiest to use and understand and integrate, but you know, they have their own things that they want to do. So they start to make some tweaks. So at this point we have, I think three or four different chains that are using forks of Gravity Bridge. So they have taken like they have branched off at some point in the past of past in that genealogy tree. And then we have, I think it's two or three that are using the, a Gravity Bridge module directly, you know, so they work directly on the current code base that the Gravity Bridge blockchain is using. And this sort of speaks to our integration with the larger Cosmos ecosystem that we are trying to make something that is generally useful and is overall something that the entire Cosmos ecosystem can get behind. Not just the instance, you know, like the one use case of Gravity Bridge chain, but everybody who needs to access Ethereum can and they, and if they wanna do something custom, if they wanna do something where maybe, you know, like Sommelier is reaching over too Ethereum to interact with LP positions there. So they want to use Gravity Bridge as less of a bridge and more as a way to run stuff on Ethereum. And that's great. That's something that we support and that's something that we can share code back and forth. So together, all of these different forks of Gravity Bridge contribute to each other, you know, we all look at

each other's ideas and say like, oh, this is a good idea. And often we'll be working on the same problems and we'll come up and we'll say like, okay, this solution works for everybody. Let's let's do it that way. Deborah Simipier (40:02): I think what what's exciting now is that we do have the Gravity Bridge blockchain out, the for chains that, that don't want something specific or they, you know, the lifts are running a bridge module along with our blockchain is, is, is, you know, not their core use case. So that's why Gravity bridge, you know blockchain is really important to maintain, you know, that kind of like neutral infrastructure that any chain could connect to. Anna Rose (40:26): And just now, Justin, you kind of alluded to this idea of like having these different use cases. I actually wanted to ask you about like the type of bridge in a way, like so far, the examples we used was very much tokens bridging over, but I know that there's also like the messages bridging over, like, is that sort of, that use case you defined there, it was more like sending messages over it instead of tokens, is messages also a part of the current Gravity Bridge or is it really focused on token transfer? Justin Kilpatrick (40:56): Gravity Brige is right now is really focused on token transfers and soon in NFT transfers the Stargaze team is team is contributing in NFT support and we're hoping that'll be done by the end of the summer. But yeah, so Gravity Bridge is not a generic message passing system. And this comes back to, you know, tradeoffs. You can have something that is, you know, fast, cheaper or good is, you know, the classic example and what Gravity Bridge focuses on is being really, really good at moving tokens across providing a high level of security there, moving other assets NFTs are not so different than tokens. And doing this in a highly efficient way, generic message passing is a different problem and it's a much harder problem if you want to achieve the level of decentralization and security that we can provide with Gravity Bridge. So this is, this is sort of, because we're on one end of that trade space, we get a lot of other users of Gravity, but we're like, oh, I see how we can add just our feature on top of this pretty easily. But by the time you say, we want to be able, want this bridge to be able to do anything, the burden of operating it and developing it goes up and up and up and up. And eventually it becomes impractical to reuse cuz the burden of running the bridge just increases and, and increases and then eventually nobody, but your project will be interested in using it. Anna Rose (42:18): Are there right now, other bridges that you know of or you know, the bridge community I doubt is massive. I feel like you probably know the other bridges out there on Cosmos, but are there bridges that are doing that, that are not Gravity Bridge based that you know of that do more message stuff? Justin Kilpatrick (42:35): I think Nomad is working on generic message passing or has a layer that involves generic message passing that they then build a bridge on top of. Anna Rose (42:45): Do you know if Axelar is too or? Justin Kilpatrick (42:47): Yes. So Axelar, I, I, I don't think Axelar is doing very generic messaging. I think they're most focused on transfers and they have some sort of messaging but in my like quick review of their white paper, you know, they can't, you know how should I put this - defining cross chain messaging is being able to send an arbitrary event from chain a and receive it on chain B. That's not a capability Axelar has right now to my knowledge. Anna Rose (43:16): Okay. How do you view other kind of bridge projects? Like is this a competitive space or is this a collaborative space in a way, like, would you almost envision DApps using one bridge for one hop another bridge for another? I'm just curious if you're like what your feelings are about the other bridge projects. Deborah Simipier (43:36): I have a lens here that that does probably look like there's gonna be some arbitrage between different bridge tokens. They aren't, you know, fungible between each other at this point, you know, I think early on in, you know, Gravity Bridges history, like there wasn't any other sort of like bridging projects. It was, is very new. And so we sort of looked at like, you know, perhaps a bit of a standardization because you know, Gravity is so aligned with Cosmos. You know, we, we were, we were building that bridge that was kind of be the kind of neutral or the infrastructure, but now I think also there, you know, a multi bridge future is where we're at, you know, the, these bridges are, you know, are here for many different ecosystems. And I think that it's gonna be an evolving discussion about now, what do we do about, you know, 10 different USDC representations in Cosmos. Deborah Simipier (44:27): Yeah, I think that that conversation is here and that I, I don't think that's an avoidable conversation. So you know, there's a lot of different discussion around, you know, how that, you know, should be presented in UX or perhaps that should be, you know you know, swapped or aggregated or, you know, there's a lot of different things that are going to evolve. I would caution us from making, you know, to quick of a, you know, any kind of permanence around it at this point, because I do think it's going to evolve and I do think it's gonna evolve quickly. So I'm really excited to sort of embrace you know, this, this new multi bridge future. Yeah. and what it could bring and you know, we're gonna be very agile and adapts to, to that kind of evolving landscape. Anna Rose (45:11): Got it. That problem of multiple kind of synthetic versions from like what, like basically the idea here is like, if you had from Ethereum to, I don't know, some DEX, some Cosmos DEX, like chain, you could potentially end up with like multiple versions of USDC from different bridges. And I, I haven't

fully explored this problem. I know Tarun, mentioned it on a previous episode and I was trying to actually like, quote it the other day and like couldn't fully articulate the problem. It sounds bad. It sounds like it would lead to problems, but I don't actually know how Deborah Simipier (45:47): I think it could also lead to opportunities. Right. Like as I was saying, there's, there's a, the there's conversations about particular, you know, like arbitrage or swapping between the tokens or perhaps aggregating them. And then into another token, I, I think I, like I said, I think that it's an evolving, it's like Anna Rose (46:02): A basket. Deborah Simipier (46:03): Interesting. Yeah. I think it's evolving landscape. I think there's also a bit there's market opportunity there. There's also the UX of that, right. That we need to balance. My thought is that the market will, you know, evolve these discussions for us. Right. You know, having, we, we are volume aggregates too, is an important kind of part of that as well, too. So we can talk about it a lot, but we should also, I think be responsive to this evolving market. What are users gonna do? Right. What, where do users want to do this? And, and I think, you know always that's typically how we tend to look at businesses around traction and users and letting the kind of market evolve the product market fit. Anna Rose (46:46): Got it. And I think this is a topic for me also for future episodes to fully like flesh out. So look for that, but it's cool to hear your, your kind of perspective on it. I wanna move on to another topic, which is that of airdrops in Cosmos and particularly the Gravity decks airdrop. Right now we're in a moment where there's tons of projects dropping tokens, some of them, you know, some of them you've never heard of until that week. I think there's Cosmos airdrops is a Twitter. It has like a Twitter handle that, like, I know my team has looked at a couple times, so let's, let's go into that topic. Deborah Simipier (47:25): Yeah. And I, and I think you know, I kind of wanna come back to where we were talking about earlier in the conversation about, you know, Gravity Bridge being this plumbing and infrastructure, you know, AUC or sewers or these, these you know, kind of long projects and how we look at what the project needs to be healthy. Right. It needs stability. It needs to just work it. You need to not think about it really. Like how often do you think about how your water gets to your home? Right. And so when we think about what an airdrop mechanism is for, and you know, how we wanna use those to support the community and support community involvement, we took a very long term approach. We thought Gravity's gonna be around for a long time and needs to be around for a long time. And we want to use long term airdrops right. So we looked at the airdrop that we did as sort of the initial sort of alignment. We also airdrop to the Osmosis ecosystem, their community pool. There's also a 9% allocation to different core entities in Cosmos that's ICF and Tendermint, Peggy JV. These folks have sort of, you know, anchored it in a community. And then, you know, airdrops, don't have to just be a once and done. That was sort of surprising to me that that was the you know, kind of constraint that was always thought about, oh, you, you did your airdrop and now it, it, that's the only thing that's ever gonna happen. And that was a really, I think kind of like surprising part of it, but the way that, you know, at least from, from our perspective, of course, the Gravity Bridge community will continue to evolve. This is that it, that evolving it over time with use and traction having, you know continuing incentives, we have 50% of the, or roughly of the community pool therefore just these kinds of things to give incentives and rewards to folks that are using the bridge and those that are building on it over probably years. Anna Rose (49:24): It's interesting. I think you just touched on something here, which is like, I mean, airdrops started the purpose of them was kind of to get engage for these projects. But I do think right now, because there's, these airdrops happening often and it's almost like people are just kind of like chasing the biggest one and they want the best free money and that makes them excited. And it's like, as I could see on Twitter, there's almost like a there's criticism of the airdrop not being big enough or not being enough or so something, but yeah, you're one thing you're saying here is that it doesn't need to be a single shot. There could be multiple. Maybe you wanna hold it out, cuz yeah. When you, when you do your community allocation all at once, who's to say half of it doesn't get dumped in the wrong way, into the wrong hands, right afterwards, you know, like maybe you do wanna slowly roll something like this out. Deborah Simipier (50:11): Yeah. And I think what you see with airdrops in the, in the past is that their users are known, right? Like they, they might, you know, know these are our side of users. We can airdrop to them. These are the stakeholders that we, that we know we have. But with Gravity Bridge you know, we're gonna have users over several years. Right. And you know, the, the bridge is just now starting to, you know, function, people can use it. Right. So it makes more sense as people use it that, you know, you have rewards and you give stakeholdership to those people that are using the bridge everyday. And those people that are continuing to build on the bridge everyday, rather than, you know, just this still kind of yet a known user base. So I, I, I think, yeah, I'm excited about how we can evolve and actually can I share, we are introducing our Gravity grants program, which has some really amazing structure around, you know, how we think about, you know, small working groups and governance around those processes. And I'm really excited to see how we can evolve that over time.

And we wanted to make sure that there's, you know, an ample amount of community pool to continue those efforts. Anna Rose (51:19): Was there any sort of distribution back to Althea, like to connect those two things? Is there a connection in that, like that's something I'm curious about? Deborah Simipier (51:28): Yes. There was both to the team and the early monetary supporters of Althea as is, you know, fair for the years that went into building this project. If you actually look at our distribution it, it, it kind of aligns with the, you know, contribution effort, right? So Althea came in the kind of largest allocation of resources in terms of time and, and and money. And you know, then we had, you know, the Peggy JV team that also came in with, with those sorts of same things as well. And then the ICF gave a grant. There never was any sort of community pool spend or anything like that. There's some misinformation that there was a, you know, community pool allocation, which that, that did not happen. So that's, if you look at kind of the Genesis allocation, it kind of follows those resources that were allocated. And again, I wanna iterate, it was over several years. So we started working, I mean, gosh, when was the first Testnet was in 2020, I think that was the first Testnet we've been working, you know even before that too. So it just sort of follows the, you know, the alignment of builders. Anna Rose (52:33): That sounds cool. Justin Kilpatrick (52:34): So I wanted to go back and talk a little bit about the airdrop in that, in the design of Gravity Bridge, we've been really committed to decentralization of all the bridges from Ethereum to the Cosmos ecosystem. We're the only one without an upgradeable solidity contract. So that means that full control of the bridge is in the hands of the validators. There is no upgrade. There is no outs. We made sure to get it right before deploying it. And we've also done something that's fairly novel in terms of the airdrop. You know, most airdrops are built into the chain by the developers. We didn't do that. Instead, we made a governance proposal type where anybody can submit an airdrop and it will execute if that proposal passes. And this gives the community direct control. So most of the time when you hear there's funds in the community pool, that's a hypothetical thing. You know, the only proposal you can submit on most Cosmos SDK chains is a community spend proposal, which goes to one address. So that's for funding more developers, which is a nice use case, but that's not really something that your, that your average user of the chain can participate in. And also most airdrops are, you know, heavily controlled. Who, who is the airdrop going to? What out exactly what amount to which user that's something that really only developers have the ability to execute. That's not true on Gravity Bridge with the airdrop proposal. It is possible for any community member to submit a proposal and for governance

to pass it. And this comes from our deep commitment to decentralization and sort of long term thinking, you know, we don't want Gravity Bridge to be dependent on any one development team. We want it to live independently and for its governance choices to really matter. And this aligns with what we do with Althea, we're building infrastructure for people and infrastructure that's supposed to last, you know, if you're building good infrastructure, it can't fall apart when you leave or you haven't done your job. Anna Rose (54:21): Yeah. I mean, there are a lot of those airdrops that seem also very shortsighted. They sort of seem like gambling kind of stuff. So, I mean, it's nice to hear that there's like thought, and longness in your thinking around, around this airdrop and, and getting the community involved. Deborah Simipier (54:40): Just to highlight Justin's point with the airdrop proposal that was proposed the initial oh one, it was done with community members you know, validators and core Gravity community members working alongside core Cosmos entities to sort of think about what would be the best initial air drop distribution. So there was a lot of thought and, you know, community member engagement that went into that, this wasn't a top down directed engagement. Anna Rose (55:09): Cool. And it sounds like there's more to come. Maybe we can talk about that. We don't have very much time left, but I wanna hear a little bit about those next steps. I had heard something about NFTs and Stargaze. What's what's going on. What's coming next? Justin Kilpatrick (55:23): For the timeline for Gravity Bridge, we're going to have IBC auto forwarding, which is where you sort of get to skip the intermediate step and go directly to your destination chain. That's going to be up by the end of this month. We are also working very closely with Stargaze, who has contributed a lot of development power to implement NFT support for Gravity Bridge. And we're hoping to have that up by the end of the summer, also working on support for multiple EVM chains. So this would be this would allow Gravity Bridge to communicate with any chain that implements the EVM. Anna Rose (55:57): That was gonna be a question actually. Yeah. We've only talked about Ethereum. Oops. Okay, cool. Justin Kilpatrick (56:04): So, you know, we really focused on getting the decentralization another bridge, right. First, you know, so that means you have to get the solidity contract completely right. Cuz there's no gradability - you get one shot. So we did that, but now we have this really wonderful Ethereum contract. Why not use it more? So that is coming. I'm hoping that we have testnets for that also by the end of the summer. So let's see. Anna Rose (56:27): But what about Althea? Do you go back? Cause like what about, so, so far it's all Gravity Bridge timeline, but Althea, are you building this at the same time? Justin Kilpatrick (56:37): Yeah. You can build two things at once, you know, walk and chew gum. Anna Rose (56:41): But like will what's is Althea also going to, becoming - the Cosmos portion, is that coming online soon? Deborah Simipier (56:48): We, Gravity Bridge is now integrated some really awesome projects like Comdex and Nym and, there's, there's just a bunch of them, right. So Stargaze also too has their their denomination over to Ethereum, Chihuahua chain. So a bunch of different, great projects. So Althea is just one project's gonna implement into Gravity Bridge too. So... Anna Rose (57:09): Got it. The Cosmos-based Althea, when will that happen or be live or maybe it already is Deborah Simipier (57:15): Very soon. So we're working on that roadmap right now. And like, like I said earlier in the conversation, we wanna encourage folks join our Discord and if they wanna be part of the validator set now is the time to jump on. Cause we will be running up, you know, some early Testnets and then going straight to the Althea blockchain itself. So it's a, it's a definitely a just around the corner. Anna Rose (57:36): Very cool. I feel like you just mentioned Nym really quickly and I realize we didn't even talk about privacy on the zero knowledge podcast and I'm sorry, I didn't get a chance to get to it in this one, but I do wanna say a big thank you to both of you for coming on sharing with me the story of Althea, Gravity Bridge, and what's coming up in the future. Deborah Simipier (57:56): Thanks so much for having us. It was great. Justin Kilpatrick (57:58): Yeah. Thank you. Anna Rose (57:59): I wanna say thank you to the podcast producer, Tanya, the podcast editor, Henrik and listeners. Thanks for listening.