Episode 244: Journey to Blockchain with David Tse

Transcript

welcome to zero knowledge I'm your host Anna Rose in this podcast we will be exploring the latest in zero knowledge research and the decentralized web as well as new paradigms that promise to change the way we interact and transact online this week Guillermo and I chat with David Shea we talk about his career and research spanning from his early work on networking mobile peer-to-peer and all the way up to his work on blockchain along the way we touch on topics like the price of Anarchy his prison work and other works that formalize the ways that Bitcoin functioned we also talk about

his work with the ethereum foundation which led to his new project Babylon now before kickoff I do want to let you know about two initiatives happening in the community at the moment the first is the ZK whiteboard sessions this is part of ZK hack and powered by polygon it's a new series of educational videos that will help you get onboarded into the foundational concept needed to better understand zero knowledge Tech the second thing I want to mention is the ZK jobs board if you are looking to find a new job or if you're a team hiring be sure to check it out over on the ZK jobs board there are a fresh batch of new open roles these roles are at ZK or cryptography focused projects like anoma Elio or web3 Foundation this is a great place to learn about relevant projects

and the types of roles that they're looking for so if you're looking for your next job opportunity be sure to check it out I've added the link to all of these in the show notes now Tanya will share a little bit about this week's sponsor today's episode is sponsored by Elio Elio is a new layer one blockchain that achieves the programmability of ethereum the privacy of zcash and the scalability of a roll-up if you're interested in building private applications then check out Elio's programming language called Leo Leo enables non-cryptographers to harness the power of zkps to deploy decentralized exchanges hidden information games regulated stable coins and more visit Leo dashlang.org to start building that's Leo Dash landg.org you can also join Elio's

incentivized testnet 3 by downloading and running a snark OS node no signup is necessary to participate for questions join their Discord at elio.org Discord so thanks again Elio now here is Anna and Guillermo's interview with Professor David Che foreign So today we're here with guest David Shea professor of electrical engineering at Stanford as well as the co-founder of Babylon welcome to the show David thank you very much Anna it's great to be here and for this episode we have Guillermo joining as co-host and actually just a note we're here in person so we're doing this uh in person I'm very excited that we get to do more of these now uh

Guillermo this was a little bit your idea putting this together so maybe you can tell us a bit about what you were thinking and why you thought David would be awesome on the Zero knowledge podcast yeah so so essentially uh I guess David and I met kind of early on and uh in particular I've always wanted to grab a drink with David and explore exactly how he went from you know through the Meandering path of uh starting from wireless networks and uh information Theory all the way to blockchain uh and in particular there's a lot of your papers that have received pretty high price and and one that always comes to mind because tarun always Raves about it is everything is a race and Nakamoto always wins which is uh I believe it's he says that there's not not one paper that comes close to it in the space and

there might never be a paper that comes closer in this space given his current you know trajectory on that but these are the kinds of things that I would love to chat about along with a number of your more recent papers you know some of them regarding ethereum 2.0 when will the merge happen I mean sorry no I'm not supposed to ask that actually I think that was one request the one request that we had in this episode don't ask I can't ask that but otherwise we could talk to you about two minutes hey I I think that's a that's a world record I mean and there you go all right so anyways um with that I'm I'm quite curious to you know kick it off that's right okay so I think we often start this with a little bit of backstory understanding the journey to get to work

on consensus blockchain generally because you didn't start there no no um I start way back my PhD thesis was on networking actually oh you like networking or was it like Wireless uh networking so in those days there's an interesting story there is that uh that was sort of before internet became the actual internet we see now at that time it was not very clear on what would be the networking infrastructure that would rule the world at risk of uh being terrible what what year was it yeah that was uh so now you are trying to entice me to review my age but it's okay it's okay so this was

mid-90s so that was when I was working on my PhD thesis in those days there was a technology called ATM now Guillermo Anna your age you probably never heard of this technology are the nurse thinking is an ATM machine or something maybe me though well maybe actually so ATM was a totally different way of building the networking infrastructure okay it was built by designed by telecommunication companies in those days there was a telephone Network right remember companies like ATT it's like the telephone company yes and then they thought hey maybe when data when we in the step voice we have data we should

have like centralized design of the whole networking infrastructure just like the telephone Network which is for data sure in those days a several Key phone companies got together and tried to push a standard core ATM asynchronous transfer mode oh okay okay and so my research was basically how to design these networks for the particular characteristics of data as opposed to voice so that was my PhD thesis going back to what he said though what era are we talking this was mid 90s okay yes this was mid 90s it was all the range yeah everyone was working on ATM at that time I was sentient I was alive you were there yeah actually conscious quite

conscious yes I was not you were not like so but the funny thing was when I was finishing my PhD thesis okay then this whole thing went bust okay why because it was completely a top-down push right and that's not how the internet came about the internet was come from the bottom up that's right and so the bottom up effort one and the top-down effort lost and so now I'm stuck because I spent you know a few years working this PhD thesis I prove a bunch of theorems about you know large deviations there was a mathematics I was using called large deviations to analyze sort of the performance of these networks in the face of data and at that time I got a

job at Berkeley so that was my first job I said you were a professor at your assistant professor yes I got a job Berkeley but there was one year of transition no time I was doing a postdoc at 18 T power lab oh okay so you didn't work yes so I spent that one you're thinking okay now that my PhD seasons have collapsed what should I work on because you know in University there's a thing called tenure that you have to get that's right and it doesn't seem like this every ATM is going to support a tenured portfolio and so that's when I learned about this area Wireless right so if you remember in the early 90s Wireless was like these huge phones and

less than a million of them are around in the whole world the only reference I actually I like I actually never saw those in person but I think on Fresh Prince of Bel Air at one point he ripped out this like gigantic it's like a water a water tank a water bottle like a brick yeah it's like a brick he just holds it to the side you're really cool if you have yes in fact in those days the bigger the better because bang is like they did have like car phones back then they had car phones yes were they the same technology I believe it's a similar technology yes but those days the bigger the better because when you sit and how can you and I put the phone on table it's like everyone knows that the symbols

massive yeah I guess right so in in those days a foam is like attached to the wall right that's what people understand the phone so although this is a very big brick it's still a step up because you can actually move it around yeah it doesn't have to be attach the wall so I would say those are mobile phone I mean it's kind of not stretching mobile phone but in any way in any case and so those days people were thinking now of trying to develop this Wireless infrastructure but then the problem was that the Spectrum for wireless is much more narrow than for y line so

for Y Line you can communicate over many many megahertz of bandwidth but in one list you only have this you know one megahertz of bandwidth this is what the FCC allows you that's what the FCC allows you otherwise you'll be interfering with other applications like military Etc that's right and so the research problem at that time that everyone was interested in how do I squeeze more bits into this very narrow Spectrum okay interesting because at that point people were now thinking remember that in why in white line people were thinking about data and so the wireless people also start thinking hey if the Y Line has data then the wireless being the last hop has to carry data as well yeah and so data has much more Demand on the bandwidth so people are kind of

worried although at that point iPhone hasn't arrived yet people are already quite worried that hey how do we gonna squeeze enough bits through this very narrow spectrum that was the uh after my PhD thesis and so I was kind of lucky because during my PhD thesis in addition to my useless PhD thesis I've also adopted a side interest and the side interest is in a subject called information Theory yep okay so information theory is a subject started by a guy named Claude Shannon in 1948 he wrote this groundbreaking paper Claus Shannon is a very interesting genius

he's very unorthodox although he was a professor at MIT he almost never had any students but he had won sort of his disciple ah and his disciple's name is Bob Gallagher oh yeah and it happened to be my advisor okay okay but at that point he was not that interested in what information Theory anymore he wants to do networking and so that's why my PhD thesis was in networking interesting but then I learned information search from him and I thought wow this is a very beautiful subject but he kept on telling me to do my PhD thesis in networking because that was all the rage networking but wait you did a bunch of large deviation bounds in your network but that's not information Theory that's

just stochastic process random process apply to networking okay but I think are there a lot of tools imported yeah there is some connection clearly from a mathematical point of view yes that's right but from my research problem point of view is very different I have a book right there called concentration inequalities and model selection which is exactly applied information theory for I think it's supposed to comma sorry so anyways yeah correct okay so sorry back so I actually didn't know you were Bob Gallagher's student there's a yeah so I have two advisor one is Bob Gallagher one is Johnson cichlis two of reverse my people one is information theorist the other one is the stochastic process person so that's how I learned the two skills set needed but then since I learned this useless information Theory

but then when Wireless showed up I figured out hey you know what information theory is the theory which would tell you how many bits you can actually push into this very narrow band and what's the optimal way of communicating and so that started my totally new research Direction and that was my first career that's the beginning of my first career that's right where were you doing all this so I started doing this at 18 T power Labs that was when my postdoc and then I became an assistant professor at Berkeley and that's where I built a research group to do this research so that was my research phase now this was 1995 to 2000.

and who was your first student again I think we'll come back to this very soon yes my first student his name is promo visvaneth okay he's now a professor at Princeton University also an information Theory or communication or what yes he was my first student and it was an information Theory okay yes okay correct it was Wireless okay yes right I mean for context I guess David has a probably the most famous Wireless textbook uh it was yes one of the more widely used I should say one of the is better yes one of the just for political purposes but but as far as I know it's it's the only one that I know and I mean maybe of course I'm biased also from Stanford which we'll get to as well but the one that is used kind of everywhere I don't

know yeah it was a collaboration actually with promote oh okay that book okay perfect so anyway so sorry okay so so you've built so yes I've been my lab I have a bunch of very good students super students and I wrote we wrote a bunch of papers but then I thought to myself okay I have these papers very nice papers winning some awards but who's going to use it who's going to care about it is it going to make it into some cell phones or not so that's not thinking I said okay if I won't have an impact I should go where the rubber hits the road in other words places where people are building this technology not in Academia and so at that time there was this sort of emerging company called Qualcomm at that

time it was relatively small company yeah that's right and my advisor told me hey uh there are some cool peoples there so I decided to spend six months leave from Berkeley to try to see whether my research are useful in solving real world problems or I need to develop some other things to solve the problems okay and I was really lucky because Qualcomm at that time was building the technology for wireless data yeah and that was called third generation Wireless that was the first generation in which the system was optimized for data the wireless system first and second generation was awful voice okay and it turned out that a problem that I

solved in my research is that basically a perfect fit to a key component of this technology and so the The Invention I had during those six months resulted in a pattern that was basically used in all cell phones from 3G 4G 5G even the phones that you're all using is using this technology what is this patent actually just out of curiosity for General context yeah so that I think that's a good example of why information theory is powerful yes because in those days a wireless is like a very bad medium because people think that hey the channel sometimes become very strong it sounds become very weak it's called fading and it's very hard to communicate over so it's a bad thing yes and people

trying to make it flat as flat as possible but information Theory actually tells you the reverse it tells you that you should optimistically use the peak of the channel to communicate to get a lot bits through and when this guy you uh Gamo has a weak Channel and um they have a good Channel and I can switch to Anna and communicate when the channel is very good so this results in sort of an opportunistic scheduling policy which is what information Theory tells me is optimal and so I introduced this idea to the engineers at Qualcomm they were very skeptical they said this doesn't work doesn't make sense to us at all I've

never thought of the problem this way but after a few months of a lot of work and convincing they finally implemented it oh there you go all right and what was the result how many uh two x oh okay there you go all right so the throughput increased by 2x holy crap yeah this might have been before his time there but like did you ever cross paths with like Anatoly because he Anatolia from Solana comes out of quality engineering I don't think a little later but assuming yeah I don't think I met in the Tony okay okay at that time yes yeah yeah which is why he's he's super into the weird crazy low-level uh tricks at least that's what I we I had him on stuff like two years ago or so and I I feel like I remember

him saying that at this point we are at 2005 where what time yeah that was uh early 2000 now okay early 2000. so that's when we decided to aggregate all this knowledge that we have and write this book that you mentioned earlier Guillermo mentioned earlier fundamentals of wireless communication which kind of gives us a unified view of the whole subject and that's usually the my research now is that instead of just solving individual problems and call it day and move on to some other areas I want to sort of develop a sort of a more coherent and unified understanding so my advisor Gallagher taught me one thing which I think I want to share with the audience because this is not just Wireless it's a very interesting way of looking at

research is that he said there's a concept called Knowledge Tree where each Leaf is a piece of knowledge a lot of people when they do research they think of growing the Knowledge Tree adding your own leave or your own twig or your own branch however he said that a really successful research is instead of growing you prune the knowledge tree oh that's why is that okay because if you prune the noise tree that means you're unifying you're understanding of seemingly disparate knowledge different leaves into a coherent whole and so in some sense a lot of my research in different fields is about how to prune the Knowledge Tree this feels uh which I think we'll get to

in the very near future as well but this feels a very Steven uh void-like approach yeah yes because I see why you two became friends yeah exactly because you know pruning a noise tree is very tied to the educational Enterprise because if you want to teach something you don't want to teach the student 10 000 different facts right you want to teach them one General principle for which the individual facts can be derived and they can go and derive new facts that's right and would you say like in an emerging space that just hasn't been defined yet like people might be like using some first principle but like they couldn't necessarily describe it yet and that's what you're trying to dig up explain communicate with those books

yeah exactly so I mean Shannon's paper is a very good example because communication has been around for 100 years before his paper communication started with the telegram telephone in the mid 1800s Alexander Bell Etc so people have been building communication system for 100 years but everybody is building their own system yeah so the telephone people building the system the telegram people building the system the television people are building the system radio people are building the system they don't talk to each other and what Shannon said is that wait a minute wait a minute all these people are just doing different facets of the same general problem which is communicating information from point A to point B yeah and through this abstraction

you are now having a unified method so if you think about all the communication physical medium that we have here nowadays Optical Wireless Y Line cable modem Etc they're all based on design based on the same principle were you interested at that time in sort of the decentralized communications happening because like around 2000 there was a lot of you know P2P stuff happening to move information I mean it's moving granted it's moving over wires and rails that already exist but was that interesting to you at the time yeah in fact um you were asking me what we were doing after my work at Qualcomm we spent the

time writing the book but at that time we were also think of finding new research problems okay and one of a research problem that people were thinking about is now suppose you don't have a central base station and suppose you have some emergency scenario where you have a bunch of nodes peer-to-peer what is the best way of communicating and we're in particularly interested in a so-called scaling problem which means as you increase the number of notes there's more and more people using how how fast can you increase the total rate of communication so that in some sense a decentralized problem because now the question is how do you kind of spread the traffic across

many different Connections in an efficient way okay so that was an open problem and we actually solved it oh okay and we find a scheme that achieves very surprisingly linear scaling that is as you put more and more notes yeah actually increase linearly wow wait what is this paper so this paper is actually with IFA okay no iPhone yeah another professor I stand for either and it says that uh hierarchical cooperation achieves linear scaling okay was either a PhD student then yes that was just her PhD thesis but what is the title of this uh paper oh is this an entire PhD thesis yeah it's called

hierarchical cooperation achieves linear scaling well we have a sort of hierarchical way of these notes cooperating so typically people think of Wireless multi-hop right so you got some traffic you forward to the other guy and that method only achieves so-called square root of N scale square root of n scan so increase the number of nodes a total throughput actually decreases per note it's under it's not it's under the linear line yeah under the linear line because why because sort of each node is have to do a lot of work in folding different traffic right but we figure out that if you do it in a hierarchical manner cooperation manner you can achieve linear scaling right

cool yes so we've got this beautiful results and we're really excited about it but then we realized that actually nobody's actually building this system the P2P stuff the Peter peer stuff anymore yeah it's the winter the P2P winter yes and I think in your one of your early conversation with uh sriram he alluded to this as well and uh so we were a little bit disappointed because we feel like we've got the optimal scheme right but you know nobody nobody's interested nobody cares right nobody cares so at that point I realized that hey maybe it's time to kind of move on to some other area where there are more promising uh pastures also I guess uh for context you know while this

result is like very very nice it does not hold in a blockchain context I'm sure David can elaborate as to why but essentially you're assuming that everyone is happily cooperating with each other this is the hierarchical this is the hierarchical case right so there's a classic question of when you have a bunch of peers connected to you know a given for a given chain for example you actually don't achieve you cannot achieve this oh event scale I don't know if there's any possibility result on that but essentially cannot achieve this o of n scaling kind of under because yeah you always have people who are doing bad things I see yeah so it's assuming a perfect world or one organization running everything no assuming wouldn't necessarily even an organization but a Cooperative world where everyone is yeah there's no person trying to kind of mess with it it's not

a hostile environment that's right information theorism very benign you know they think the world is very good that's right in fact at this similar time frame uh Timber of Gordon I don't know if you interviewed him not yet but I know it's a very interesting guy he starts thinking about uh a problem where each note is not willingfully collaborate but cooperate only based on the incentive basis and he was trying to figure out sort of what are the good Nash equilibrium that's right and uh so that was another line of work and there's a lovely term for this it's called the price of Anarchy if anyone does want to look it up which it turns out the price of Anarchy is the best possible case if you had a central

planner so if you had one person directing the flow of ever you know traffic in this case uh data for example uh one organization that is the best possible you could do of course this person could just benevolently say we are going to maximize the amount of data that gets through here okay period if I set it as law it's going to happen the price of Anarchy says something a little bit different and says if you instead allow people to like act according to their own incentives to pass data or not you actually achieve uh sub-optimal result the price of Anarchy quantifies how sub-optimal it is right it's the difference between those two things that's right and you can imagine there's a gap because anything that people are incentivized to do by themselves certainly uh Central planning

organization can force upon them can say this is you know what you want to do but on the other hand it's not true the other way around right you cannot take a very nice plan and then expect it to be kind of what people call incentive compatible you cannot expect people to follow it just by their own will even you know according to their own incentives cool so this is uh now I guess mid to late 2000s right is that about yeah it's late to it's about two late 2000s okay and then uh I believe around there uh you were poached actually right or was that a little bit later so beef between then and blockchain there is another story okay but I don't know whether we want to talk too much about that story because we want to get

to blockchains I guess right we do want to get to blockchains but let's let's hear a little something about it a quick summary would be lovely yeah so information theory is basically about sort of what's the best way of doing things so at that time I was looking for something else and I just happened to stumble in a random workshop at a place called Newton Institute in Cambridge where they talk about this problem called sequencing genome sequencing oh that's right so basic genome sequence is a really interesting problem it's a jigsaw puzzle you take a very long sequence three billion symbols that's our genome you want to read the whole sequence from beginning to end but nobody can do that no no instrument can

do that so what you do is you chop it up into very small fragments called reads and then you want to sample it enough so that there's a lot of overlap between these reads and then you sort of try to fill put the jigsaw puzzle together to get the original sequence so that's the sequencing problem and of course that's a very important technology that's how the human genome was sequenced in the first place but and as the information I start asking the question okay so you get data you want to recover the ground truth well what is the minimal amount of data I need to sample right how many reads do I need to sample because that's an important question because if you can get by with few reads then you can sequence more organisms

yeah for example using the same budget cool and so we start thinking about this question and then we provide Solutions problem and then we develop some assembly methods to try to achieve this limit so that was in now in the early 2010s yes yes so that was our focus of our group at that time and that kind of culminated an interesting paper just you know before we get too much into the blockchain which I I actually just pulled it up it's a hidden hamiltonian cycle recovery via linear programming kind of explains all of the results you had prior yeah that was part of the yeah that was part of the research right um yes so yeah so it's a really cool paper by the way it's it's actually like

it's an insane result which is very shocking but uh essentially yeah it says something like we take a this problem is known to be very very hard for computers to solve but it turns out if you have enough samples so if you if you take enough reads it actually becomes extremely easy and doing the the you know the silly thing of kind of putting everything together uh this is called you know whatever a linear relaxation actually achieves exactly the right result as if by Magic you know yeah so a lot of people when they look at the assembly problem the standard approach is on a computational basis you want to find efficient algorithms to do it but it turns like if you look at it from an information Theory point of view which is the minimum of that amount of data it turns out it gives you inspiration

directly of finding efficient algorithms to get those information limits and that's what we're working on so that was one of my introduction to sort of data science genomics and I worked there for a few years now one thing I observe about that area though as opposed to whitelist is that the people driving the research agenda in genomics etymologist um people who are like me developing computational tools are like plumbers they just call you in accordance and say hey man we have this data set or I have this application can you help me to actually you know analyze this data

and I don't know about you but plumber of course plumbers make a lot of money so that's good but you know the status symbol is a little bit a little bit low so I think the problem there is because there is a the engineering is kind of self-service to the science right right and I'm primarily an engineer not a scientist right I would not be able to identify the next groundbreaking biological problem to ask I have no idea and so at that point I realized that maybe this is not an area which I want to spend the rest of my life in and so again I'm on the search so I've seen a bit of a pattern yeah

it's interesting yeah maybe it's a restlessness perhaps yes but it's probably I mean I think I have something similar I've switched through many Industries and focuses so at the end of that though you do have this you tend to have a broader view or sometimes you can pull things from these other spaces yeah and post things he does that's for sure I believe so you know sometimes like my PhD thesis right I spent four years doing it and it turned out to be not very useful it doesn't mean though it's like a whole lost everything lost because I learned a lot while doing it right trying to find the right problem learn some mathematical skills so it's always useful so I tell my students always that

it's okay the PHD thesis does not change the world it's okay yeah but the more important thing is that you should learn while doing it because what you learn will be useful for your next stage of your career whatever you choose to do definitely so I think we have maybe arrived we have actually at blockchain yeah so now we're in 201 8. uh and in fact actually that is I believe the year that uh we met or did we meet in 2017 around there yes we met probably in 2017. so for for context uh I I think I was your head ta for a very specific class with Stephen as well called introduction to linear algebra um hey that's the class I took no not at Stanford yeah maybe you would have been

a mathematician then if I had done it there yeah exactly um but so okay so that's that's actually where we originally means they were co-teaching this class right so that was when I moved to Stanford oh you had just yeah I moved to stand for in 2014 time frame okay one four one five time frame and linear algebra was one of the course I started teaching that's right in the first two or three years yes that's right oh no you're right it was 20 sorry it was earlier you're right it was 2016 was when the course was initially taught if I recall yeah I think you were still an undergraduate if I remember correct I I was I T8 that and then convex right afterwards of our call although you did not it was Sanjay I believe but anyways okay so digressing so I love teaching freshmen so that was

a freshman I love teaching freshmen because you know freshmen to come in with very little bias and it's great to be able to sort of engage with them at that point yeah I think it's great and actually I'm still getting comments about that class that that class was actually what turned people into doing no more math actually they were like math is formal thinking yeah formal thinking because it trains people even things even more generally as like uh you know math isn't just you know let's prove X thing for why reason it's very much uh you know its own art in a way so anyways that was interesting because of that but okay so and and that this is this is around the time when you went down uh down the rabbit hole I believe I think that's the technical term for it uh if I recall correctly and

what was that first project then what kind of triggered you working on something blockchain related yeah so as I mentioned I was looking for something new in 201 8 uh beginning of 201 event happened which is Bitcoin went to the peak the peak was almost 20K almost 20K nowadays when we see Bitcoin 20K is like the end of the world but someone with a little bit longer perspective will tell you that 20K is actually very high already because it was the last Peak that's right and so at that time there was some interest in doing research in blockchains and I was recruited actually uh in your podcast with sriram he

already mentioned he was recruited by promote his advisor in working on blockchains and promote being my former student also recruited me got it and he finally recruited a bunch of people not only me and Sharon but a bunch of very good people and we start forming a group doing research in blockchain and I took a year of uh absence from Stanford to focus my effort into learning about the subject and trying to understand what are the interesting problems because you know blockchain are typically two types of people from Academia work on one cryptographer yep and two distributor system those two are the main branch of science that enters into blockchain but we are information

theorists that's our background very few information theories work in this area and so we thought hey first of all there's a lot to learn but you know sometimes when you move into a new area you bring your own perspective something interesting may happen for sure so we are so we kind of did a bet on that and we spent a year working on it and uh so that led to our first paper uh prism that I think shiram also mentioned yeah in his podcast I should mention that podcast actually so we have another episode we did with sriram Kanan uh and I think it came out three four months ago We'll add the link to that in the show notes if anyone wants to check it out actually at this point from this point on there's going to be a lot of overlap in terms of the works because it

seems like you co-authored together quite often yeah sure I'm and I work very closely together we as sure I mentioned in his podcast we talk on a daily basis because you know if you want to learn something new is really better if you have a bunch of people talking to each other then you yourself trying to read like Godzilla number papers and honestly blockchain papers are either like bogus yeah in terms of what they claim or the rigorous ones which are very good but it's extremely hard to penetrate oh yeah a lot of them will be using their own words for the same things I don't know if you've noticed that oh it's exciting it's like it's a new vocabulary every time and then you have to you're like oh that's the this and this other one

that's right so you know the core of blockchain is consensus right but apparently there's no consensus on the vocabulary well there might be eventual consensus of the vocabulary but that might be as T goes to Infinity so um you know if you want to wait around that long I'll let you do that but unfortunately I think uh each person has to come up with their Arizona stone for for this uh this translation layer so to speak you know now that we've gotten to prism do you want to describe what actually I don't know if you're the original in the episode I think he did but I think it would be great to actually hear it again yeah and maybe you maybe you just find it a little bit differently too yeah yeah maybe I can take a little bit different perspective on that problem so yeah sure I mentioned

the two big problems at that time was how do you increase the throughput and how do you reduce the latency of Bitcoin and as information theorists we start asking okay all right if you want to increase the throughput or reduce the latency are there any fundamental limits right so one of the let's let's have a ruler to figure out what's the fundamental limit first and then we try to figure out okay how far is Bitcoin from these fundamental landmarks and let's say we can bridge the gap so first observation we had was Bitcoin is really far away from the fundamental limits because you know

Bitcoin is a distributed system yeah right so distributed system is limited by two things one is the propagation delay of communication right you've ordered notes in one place there's no consensus issue because everyone can get an instantaneous update as to what the other guy's doing because of the delay there is a split view issue so that's one thing to delay yep two is the throughput is limited by either the processing speed of the computer or the communication link but both are very fast we know we're fast very fast computers and we're very fast networking right that was my early career okay so I was sensitive to that right in fact we measure Bitcoin

throughput and we figure out that Bitcoin throughput can fit into a telephone modem wow from the 90s 24. so that's 28k are you saying that's not causing the difference so that's not causing the limit that's not besides okay see our communication right your cable modem we're talking about hundreds of megabits per second hundreds of megapers that's right so many orders are mounted larger so then we start figuring out so what's going on why why is there such a big gap and so that's kind of motivated prism it sounds like I don't know if this is at all related but it sounds a bit to the like a throwback to your Anarchy's cost or something oh yeah the price of Anarchy because you're comparing it to a

central a centralized version all right so it's actually yes in some sense yes um yes but the price of Anarchy result also states that the loss of performance from decentralization is not big is actually yeah it's in fact constant yeah it's a constant Factor so that's the point in a lot of faces yeah so then the challenge is whether or not one can improve Bitcoin to get closer to those limits and uh what we figure out is that Bitcoin looks like a really simple protocol right very simple protocol everybody does exactly the same thing like everyone else which is to mine and keep on trying to solve this puzzle to

generate block and then once you generate you work on the next block so it looks like a really simple protocol but it's actually packed with complexity so this fellow Nakamoto or this group of fellow Nakamoto really smart because if you think about it if I mine and propose a block right I'm actually doing multiple things with this block one is I'm trying to put new transactions into the blockchain but two is I'm also voting for all the previous transactions in the previous block because if I add a block that means I am increasing my trust that this is the correct history and therefore I'm voting for all the transactions previously in the history so actually I'm doing at

least two things and if you think about it the first thing a putting transaction in is about throughput the second thing about voting was about confirmation and therefore about latency oh so to be able to solve these two problems first I need to disentangle these two problems yeah because obviously it's hard to solve two problems at the same time okay so basically prism is about trying to break the blockchain structure into three types of blocks one purely for proposing two purely for voting and three purely for carrying transactions and by breaking into three types of

blocks we can scale up the behavior in a separate way and that's basically prism were you able to identify in that breaking also which one caused most of the kind of Delta between the centralized and the regular like was one of those more responsible than others for any sort of like lack of performance okay so the problem of Bitcoin is that Bitcoins cut interesting because consensus it's actually a 40 Euro problem okay right but Bitcoin is a consensus protocol it has no connection absolute whatsoever to all the 40 Euro protocol but yet it's the first one that's widely deployed yeah in some sense in an

internet global scale and so the the the the real reason why Nakamoto could do that is because it slows down everything oh you think he just sort of didn't care about right so if you think about his typical consensus protocol where you have a hundred nodes yeah then everybody is born at the same time so there's a lot of complexity in trying to deal with hey you know many people are talking and some people may be talking bad things wrong things and trying to disentangle that's very difficult right now can we say forget it I am not interested in speed I'm only interested in a very robust system that can be used on global scale and so what he did was it slowed down everybody

so that only one person in some sense can speak at a time and so when you try to speed it up that's when the problem starts because then you're confronting in some sense the 40 year old consensus problem but now you have to deal with many other issues like proof of work or permissionless that people can join yeah so what we basically did was we think of instead of having a lot of people voting we sort of allow sort of each person to have sort of a voting chain so each chain is still a Nakamoto chain but now all these chains are regulated by Nakamoto problem

mechanism but yet they can simultaneously vote to speed up the confirmation so I would say the speeding up of the confirmation was the most difficult part of the problem interesting because that was what was the voting Dimension yeah the voting Dimension was the most difficult yeah but did you do it on each of them so you were trying to optimize each of them that was the hard one how did you do it on the other ones yeah so we first solved the voting problem the fast confirmation and then we realized that what Nakamoto did was the following he said if you propose a block you have to put all the transactions into the block and verify it and then you can propose it but that means that the the throughput

of the system you want to increase the throughput your block size would becomes bigger if the block is bigger then you have a lot of delay and you have a lot of delay you have a lot of consensus problems so-called forking problem and so there's a limit on how big the block size can be in the case of Bitcoin is usually one megabyte you obtain one megabyte and so what we said is hey why don't we just take the transaction out of the story and have a separate type of blocks on this transaction and just in some sense have hashes or representation of those transaction in a very small block and you can pass it around very fast and then you can vote on that and then make references to the transaction and so this idea actually sort of became

nowadays rather popular and it's used in many different protocols it's essentially separate out the execution from the consensus this sounds oddly familiar no who else has done that recently or has talked about doing that yeah so this might be doing it soon soon to you cool right essentially yeah so so uh at a high level I love the the idea behind prism actually is is um is quite an interesting one is like evaluating like I believe actually it's a subtitle of the paper but it's like essentially evaluating the physical limits of blockchain yeah it's called deconstructing the blockchain to achieve physical limits right and and here the physical limits are of course that's

given to you by kind of the traditional you know gross metrics such as Network delay uh or or bandwidth correct right then starts leading into a number of other papers though uh this one's 2018 or 19. yeah we finished in 2019 end of 2019. so since this was the first problem that we worked on we thought hey Bitcoin is the thing to improve now after we spent all this effort on this paper well I think there's another pattern okay oh yes exactly like you're gonna hear now that's often the case when you work on the first research problem is that you look at pump very fundamentally but in some sense the interest in the

field could have shifted while you're working this problem that's right okay and what happened for us is that proof of work has shifted to proof of State for sure so you may ask hey your paper is so great why haven't I heard of it this guidance what is he talking about right I'm I I'll tell you that paper is great but I still agree I I understand why you may not have heard of it and really the reason is because the center of mass of the field has shifted to proven stake at that point yeah okay and improve our stake the problems are quite different and so one of the when we finished that paper and we realized that the cinema

shifted so a natural thing was okay can we sort of adapt a protocol to proof of Stack because a perco has still a lot of interesting advantage and that led to a more basic problem which is okay can you adapt the longest chain protocol which is like a model protocol to proof of stake right that's the more basic question yeah that we ask okay and so then we start looking at sort of the protocols that people are playing around with okay and we realized that proof of stick has one big problem compared to proof of work there's a problem called nothing at stick nothing at stake nothing is thick so in proof of stick I know so suppose

you have you you think about nakamoto's protocol right the protocol is you should always mine on the longest chain you should always grow in a longer chain it's a very simple protocol one sentence summarizes it yep but then you ask well is there an incentive for the adversary to go and mine on other blocks maybe to create confusion and the answer is really no because if he tries to mind another Blog then he has to consume computational power he has only limited budget of his hash power and then he can't mind on the tip anymore so there's a very strong incentive for him to just forget about every sorry action just follow the longest chain but for proof of stake is different not a computational resource no and you

can use that stick to try to bet on many different blocks and see hey maybe I can win on other blocks and if I can win other blocks because the lottery is different so that's nothing a stick problem and as a result you can like grow a forest and try to pick out the longest chain among them and you can win against the honest interesting and that's actually a protocol that uh Bram Cohen at um Chia Aya was building okay because there they were using the same concept of longest chain but on proof of space so proof of space and proof of stick is very similar because they both have just nothing at stake pumping and so we realized that okay the analysis of that protocol is

extremely complicated now because you have so many people growing yes so many chains growing and so we that led us to sort of try to find sort of a unified framework of analyzing all possible sort of longest chain protocol whether it's proof of work proof of space or proof of stick and here we get to I believe tarun's favorite yeah so that led to this paper everything is a race and nakamotos always win and what is that actually which is kind of funny because you nerd sniped a very famous statistician who as far as I know has no idea about anything about blockchain which is Amir dempo right before we well yeah before we get too deep in the in the results how did you even achieve uh nerd sniping a

statistician actually so at that point yeah we spent yes yeah at that point we spent about a year almost a year working this problem we're trying to figure out in fact our original point was not to have a unified framework an original problem is just to solve this cheers protocol problem sure yeah because they didn't have a good solution for this and they were asking us so okay how do you sort of deal with this problem because it looks like the security is very bad because you can do this nothing a stick attack and um so we spent months working this problem with my students we're stuck and then I met my old friend office attorney okay who is Amir dembos buddy so they work in probability okay in fact

he was the one who worked with me helped me in my PhD thesis on large deviations because it's the word expert in large division so I knew it from 20 to 30 years ago okay but then he happened to be visiting Stanford and he asked me hey remember those problems were working 25 years ago I'm still interested in those problems can we do some more collaboration I said no I've moved on several times as we found out repeatedly but then I said I'm working in this area called blockchains he looked at me and said what's this blockchain [Laughter] and then I thought okay how do I explain to this guy who knows nothing about blockchain in a way that is going to make him want to do in a way because it's not like there's something called

crypto yeah yeah I realize that there's nothing a stick problem has a very strong probabilistic nature because you're kind of growing your tree in an independent way at many notes so it's like a random tree and there's a lot of things known in probability about the evolution of such a tree and so I figure out a problem is can really contribute on this problem and so I strip away all the details about the cryptography and just turn it into an entirely a stochastic process problem right okay and then I can explain to him and then we start collaborating and Amir dembo is his collaborator so he also brought Amir

in and we start talking and when we came up with a solution because not only we solve this particular problem of the cheers protocol problem but we also solved a unified problem because why because we stripped away all the details already yep so now we can apply the framework to many different types of problems so why do we name the paper everything is a race and Nakamoto always wins in nakamoto's paper there is one page of math in that paper about eight pages that page of math is basically analyzing the security of this protocol through a race between the adversary and the honest Miners and there is a joke that

the only distribution that computer scientists know or is the poisson distribution so uh there's there's a reason why maybe it's enough already it well it turned out to be uh so it's a two as a race it's a stochastic race because of the randomness in the mining but he never showed that that attack is the worst attack and so the question is because in consensus people are always interested in understanding what's the worst attack because otherwise if you design a protocol that just deals with one attack what happens if someone else came up with another attack yeah that you have not thought of yet and so that was the open problem so what we showed in our paper is that in fact

it is the worst attack okay no other attack is worse than this attack and not only for Bitcoin only for proof of work but also for proof of stack and proof of space so that was our main result and that's why we call the paper everything is erased so all the attacks can be transformed into a race and Nakamura always wins because they figure out intuitively that that is indeed the worst attack without being able to do the math to support it so we did the math basically so that's just one thing to show it yes because you have to show I mean it's not trivial because the attack space is infinite Dimension after this I know that and stop me if

there's something in between here but I know at some point you also started to kind of work in collaboration with ethereum yes and there it seemed like were you going back to the prison work or were you also was it also coming out of this work like these sort of breaking apart of things I guess yeah so remember in University research is often curiosity driven so it's not like you're trying to build a startup right it's like okay I'll just solve this problem next time solve this problem research has the liberty of trying to sort of identify interesting problems whether or not it's related to the previous poem you're working yeah so that was now bring us into 2020 mm-hmm that was the beginning of the pandemic I

believe and I was teaching a blockchain course at Stanford online and uh we have to find some projects to work on for the students and at that time ethereum published a paper on their consensus protocol for ethereum 2.0 now we just call proof of stake ethereum it's the beacon chain protocol yeah and that was the one that they will be implementing towards the merge okay and then I asked my student who was doing a project and say hey why don't we try to understand what this protocol is doing maybe we can find something interesting to work on and then we spent a lot of time reading this protocol it's a very complicated protocol and one thing we observe is is unlike any of the traditional protocol

it's not like nakamoto's longest chain protocol nor is it like a standard Byzantine for torrent so 40 years history protocol it's kind of a conglomeration of a bunch of ideas and so my question for a student is okay two question one is what objectives is this protocol is trying to achieve so why are they building something from scratch why don't they just take an off-the-shelf protocol and optimize that and build it and by the way the students earn them right sorry this is erdem wait okay no Strat is uh my student so that was his project okay his project and also with your Kim and understand I

guess as well and um so that's number one question number two is okay if those objectives can they achieve can this protocol achieve those objectives in the paper they never actually spelled out what objective they're trying to achieve okay and in the ethereum paper I mean the objective is proof of stake something yeah the objective is the proof of Stack they have some idea that they want to be so-called accountable that means they want to punish people but yet they want to share some characteristics of their ethereum 1.0 which is this notion of dynamic availability keeps on growing did it also have a little bit to do with just the fact that there had to be a migration and like how to do that

migration and if you do the splitting then it becomes a little bit part of it can stay the same part of it gets reintroduced I mean as I understand now it's like yeah switching out consensus basically yeah I think that was original thinking was to kind of put a gadget on top of ethereum 1.0 yeah but then it sort of evolves to kind of like something very different so there's no such putting Gadget anymore but still the research thinking was coming it's still similar right and so that's kind of interesting thing about research about engineering development is that often you're trying to solve a problem and the problem has changed but your thinking is still the same and so now you ask the inventor and say why are you doing this is that oh yeah that's a good

question it was because we're trying to solve some problem Oh but that problem doesn't exist anymore right right right right okay and uh so that led to our paper is called app and Flow protocol and uh in that paper we formulated exactly what ethereum is trying cheap in fact we got in touch with them and said hey you know maybe these are your objectives yeah yeah actually these are objectives so we came with these objectives and then we realized that the ethereum protocol is actually not secure the one they proposed in that paper it's not that time yeah okay yes and we find attacks on that protocol so that's the second thing and the third thing is we

constructed a protocol that actually is secure and also achieves the objectives that we dictated who's the we in this and at this point yes so this is with new threat and your Kim so you're your students and your kibner cool so those are the two students at Stanford in my research group okay I guess you looked at it shared a lot of these results did it change it has it changed due to that yes so as a standard in security when you find attacks you have to talk to you should talk to the you just protocol people right you don't go and say oh okay so all right go for it build it I'll be first yeah so so we engaged them and then we started a collaboration

so one thing we found was to get it with them we found even more attacks oh wow okay so the first step was in fact we have a paper collaborated with ethereum foundation called the three attacks yeah so two of them we found one of them they found okay so you're working with primarily there was it with like Justin and yeah Justin dank red dunkrat and there was a group of younger people okay uh and we have bi-weekly meetings to talk about ideas and we realized that there were more attacks and so we proposed a few things to try to improve the protocol and they're still ongoing work really still ongoing work I think yes but what

were so like changes I guess you proposed some changes shared disclosures did it change the design or was it more like this yeah not significantly um so one thing about research and technological development is that the timing is often important yeah and we know that the merch is happening soon and there are 10 client teams 10 client teams working on this implementing this new protocol so it was a little bit hard to make very big changes in the short time scale for sure so I think our contribution was to identify some problems that they could look at and have some short-term patch but at the same time come up with longer term design that they could switch swap in maybe at a later point of time maybe not

the merge but maybe beyond the merge got it so that's what we are working on right now cool nice so the project that you are also co-founder of Babylon I need to I think we need to understand what like is there a link between the work you did with ethereum and that and we should learn a little bit about it actually yeah so uh there's no link from a from a deployment point of view okay but there is a link from a academic intellectual or from a research point of view so let me explain that a little bit more to do that I need to explain a little bit more about our solution to right the objectives that ethereum 2.0 was trying to achieve okay so the objective there was trying to achieve

two objectives one is they want Dynamic availability that means they want the chain to keep on growing no matter what the participation rate is I think sure I'm already discussed quite a bit of that so I won't elaborate too much so in any proof of work protocol you have this property and you turn one point where's this property and they want to keep this for your third 2.0 but at the same time they want to achieve a property called accountability which means that if you commit a crime as a validator you can be punished you certain 1.0 or Bitcoin doesn't have this property they want this for your term 2.0 and in fact that was one of the things that proof of stick can potentially give and they want to exploit that it turns out there's a negative result which we proved is that you cannot get

both at the same time you cannot be accountable as well as Dynamic available it's impossible right there's no protocol which can do that and so the best you can do is kind of create two Ledger where the longer Ledger is dynamically available keep on growing okay and then a prefix Ledger a shorter Ledger is accountable that means what that means that if you or have important transactions and you want to protect it better then you should wait a while before the transaction get into the shorter Ledger right if you have easier transactions like buying a coffee yeah then you say hey I want fast transaction I don't need accountability I can move

on is it is it like could you use the word asynchronous here like asynchronous consensus or am I going going in the wrong um asynchronous usually as a description of the network assumption okay so here is a little bit analogous to maybe I can use the Bitcoin as analogy just analogy so in Bitcoin when you confirm a transaction you can ask yourself how many block deep do you wait until you confirm a transaction many people wait two blocks one block tip they confirm some people say six block did right some other people can say 20 block deep so well in fact there's no single number that can be that needs to be determined system-wide okay

so if you think about it what does that mean that means that yemo who wants to buy coffee is now trusting the whole block as The Ledger the order blocks yep me who is buying a car is only trusting a prefix of this Ledger up to the sixth block deep okay so in fact that was one of the really cool innovation of Nakamoto so in some sense we had applied this principle to ethereum problem is that the shorter Ledger is accountable but have they implemented that design yes well I know that there's a consensus in the execution yeah no no oh so ledgers in the consensus yes but I didn't know okay yeah so you would remember there's

this thing called the Casper FFG yeah it's called a fanatic Gadget and definitely a gadget determines the accountable Ledger and then there is a so-called ghost which is growing the dynamic available Ledger okay so if you tease out the protocol there are actually two ledgers there still going towards Babylon what did you take from that all right so now I need to say okay so if you think about it accountable is really coming from the history of bft because bft is a kind of built-in finalization is very similar yes and so the best protocol to give you

accountable Ledger is actually a bft protocol not a longer chain protocol [Music] comes from Nakamoto so the best protocol the simplest protocol is the longest chain protocol and so once we realized that I said hey why don't we just take a longest chain protocol and a BFD protocol off the shelf both of them and but compose them in a nice way so that they can communicate each other in a simple way interesting to give you this two Ledger solution so our construction is instead of like the ethereum approach which is to build a brand new protocol we try to be composable so we try to put an off-the-shelf BFD protocol together with the longest chamber interesting

chemical solution okay and so that led us to sort of a sort of a further level in our understanding of consensus is that often when you build new consensus protocols you don't have to start from scratch yeah you can try to take off the shelf technology yep and compose them and try to get the best of both worlds so was this the first time I mean in the work you had been doing previously you weren't really working on consensus specifically until I guess prism or would you say you were I've never worked on consensus okay do you still say you don't because I mean this no I'm working on consensus now okay the area that I work in in blockchain is consensus perfect okay that's the that's the area I'm working

um but I've never worked on consensus before but of course while doing this I learned about sort of order history yeah because one should not ignore history right I think research is about okay first you try to look at problem with the blank slate but once you have some understanding you should look back at the literature and see what's been around and not be ignored totally right so going back to Babylon this idea of composing of the Shelf protocol can take it one step further and the one step further is instead of just composing protocols you can compose existing blockchains okay so that's a little bit different a protocol is something you can you deploy yourself someone already gives you the protocol someone gives you sort of the

algorithm and you can deploy it right that's composing protocol right but composing blockchain is really taking existing blockchain like Bitcoin yeah a running blockchain and composing it with another protocol that you could develop together to form a more powerful blockchain and so we start thinking is that hey you know there are two developments that we observed one is that in an ecosystems like Cosmos okay there are many these so-called application specific blockchain which the idea is that they want to give the developer the flexibility to build an autonomous

blockchain yep they can be designed slightly differently yeah optimized for diversity for example in the Mev application Etc right however they lack the powerful share security platform of ethereum for example but then we realized that actually there is some very secured resource out there which is Bitcoin and so the Babylon project started when you start thinking how can we use Bitcoin to not to replace the autonomicity of say Cosmos Zone but to complement the security of the cosmosome and so this is a composition problem we take a

cosmosome and we want to communicate with Bitcoin in a succinct way yeah in order to get extra security that it cannot get by itself but can you when you communicate with the Bitcoin Network are you always just like using the memo field like what can you do how can you lock something in I actually this is sorry this is just like my ignorance on bitcoin but I don't actually know how to use it as a checkpoint so the key here is really to use Bitcoin as a Time stamping device yeah so uh Nakamoto actually mentioned in the paper that what I'm building the Bitcoin is actually a Time stamping server okay and so the the real security benefit is

really for the proof of stick chain to timestamp the events that are happening on the Chain yeah so that they can be everyone can look at those timestamp so what is the timestamp right a timestamp is really the fact that I'm sending I'm saying okay an event has happened to prove a stick chain that trigger a transaction that I sent to the mempool of a Bitcoin miner the Bitcoin miner includes it into the next block it mines that transaction gets enough deep into blockchain secure and now I have a timestamp the timestamp is the which block it appears now this timestamp is not like a very

accurate clock because Bitcoin blocks yes you know you have one block every 10 minutes so it's kind of like a pretty inaccurate talk at a short time scale okay but at a long time scale is a very accurate clock because for example if you get a block 20 block deep in no one has seen a block has been replaced after it got 20 blocking no one has seen that in history of Bitcoin that's right okay so it's very reliable at a long time scale but not so accurate in the short time scale I think but and maybe you just said it but I didn't I missed it but like but I I still don't understand like how do you connect it how like where's the connection made if you're talking about an external blockchain how does it get a message like into it okay so so

now we're getting a little bit technical okay one of the powerful ideas in cryptography is hashing okay now I have a block I've created this blog in approval stick chain now two times in this block one thing I can do is I can ship the whole block to the Bitcoin finder yeah and put the whole block into Bitcoin that's impossible because that goes back to our original statement that Bitcoin has a very low flow Point yeah if everybody does that then Bitcoin will become least one so so are you hashing it so you hash it and then you have a hash yes and you have 120 256 bits okay if you press the hash as and you know cache in the memory field in the memory together with some signatures saying that you're validators

I think I've approved I think you had said mem field and I thought of mempool but mem field got it so it's a Memory it's the yeah it puts into the memory of the Bitcoin miners and now they put this hash as though it was a regular transaction yeah and actually there is a special field yeah it's in the memo Fields yeah it's called up return actually it's a very strange oh it's operating very very nerdy term very nerdy term it's called up return it's for putting arbitrary data into Bitcoin I see yeah and this transaction will get into a block it will be fixed forever and so this is the timestamp of that hash interesting and because of the cryptographical security of hashing nobody can create another

block which have the same hash yep so therefore the link between the hash and the block is secured Babylon though was work project I guess conceptually but is it also now company yeah so we had this these ideas last year and then we raised a seat round of funding and now we're building the product okay and what is the product is it a tool yeah is it the bridge between the two things like because it or is it a zone of its own that's and is it going to be Cosmos actually yeah that's a good question example so Bitcoin is here you know it's good so what we're

building is in some sense a cosmos chain which we call Babylon and this Cosmo chain is like a connection between Bitcoin and all the other IBC basically I guess you're going to be IBC enabled yeah so you're like but just to bitcoin using this particular technique for time stamping the hashes so the thing is that time stamping has to be done in a smart way because Bitcoin is very limited space yeah so our technology is sort of optimized this time stamping yeah and then we use IBC to communicate with other Cosmos zones one way to think about is that you know bridging is about often bridging

token from one chain to another what we're doing here is we're bridging security would you almost call it like okay it sounds a little bit like a roll up on bitcoin that's IBC enabled would that be at all fair I know Roll-Ups have a different thing and I like I've done yeah I just did an episode about actually the comparison of like Roll-Ups to Bridges and stuff but maybe roll Up's the wrong word but it's like deeply connected to the Bitcoin world so it does have some similarity row up that's right so when we're thinking about Babylon is aggregating many checkpoints of many proof of stick chain yep and represent that by one checkpoint efficiently into Bitcoin right so in that sense you can think of a Rob can do

this job but we decide to use the cosmos chain as our infrastructure to build this instead of a row up because actually Cosmos SDK is a much more mature technology than building a row up number one number two is that IBC is already an established technology became different cost more chance so we can immediately leverage that yeah so I think that's why we chose as an implementation platform a cosmo chain but you do I do agree from a functionality point of view it has some similarity a row up although I guess the different like there is no transfer of like token though there's no you're not locking on one side okay the more technical term is that we are not using Bitcoin as a settlement layer I see

right that's right that's right here's actually a good question so uh when let's say I were to you know have a cosmos ecosystem and you know a chain right and I go and I wanna I wanna have this checkpointing actually uh even just this is a very type of question but uh how do you so what do I pay you specifically A and B how do you actually um how do you even bid for the transactions for the Bitcoin manager so that's a that's a non-trivial problem as well right you have to have something to be included to be included yeah you have to pay for that so yes Bitcoin yeah so and so first of all uh Babylon the chain has to pay Bitcoin that's right to get the checkpoint in yes but that's the

business between Babylon and Bitcoin no of course of course but but somehow it has to get translated to people who are you know paying you yes so that's right that's our cost basis right from a Babylon point of view right right and you can't just buy but I can't just keep on paying and not get anything yeah so when others proof of stick chains Cosmos zones put checkpoints into Babylon through IBC they have to pay that's right actually is there anything else that you want to share about Babylon maybe where it's at or like if you have any sort of road map yeah so maybe a few words so right now we have a uh engineering and research team the researchers mainly

come from Stanford uh not not surprisingly the engineering team is a really good layer one Engineers around the world so we have five Engineers working for us and three or four researchers that's our team right now uh we are working towards um a demo a cosmo verse I would love to but it's so there's so much travel this fall it's gonna be yeah it's like three years that's right oh wait that's right because that was a million and then uh Eep cc is I think so or Defcon yeah yeah but it's not at the same time yeah I know some friends who are going

to like travel in the middle yeah it sounds pretty lit yeah so we're hoping to demonstrate our ideas there and get some feedback from the cosmos Community nice so that's our next step in the road map and then we'll use that feedback and build a test net and hopefully we'll find some interested Cosmo zones to do a joint test net integrated test net with us very cool so that's the roadmap in the next six months yeah nice oh actually I have a question why why wouldn't people uh use the the protocol to bootstrap is the idea mostly for bootstrapping or is it for actual like kind of you know continual protection instead of speaking Yeah so there are two two or three use cases that we are working on one is

um reducing the unbonding time right so that's a good point cosmosome has a 21 day and burning time uh using a process called social consensus which basically means that the off chain you have to agree on what's the canonical chain we can use Bitcoin to replace social consensus using our technology and we can reduce the important time to one day so that's the number one use case the Second Use case is as you mentioned bootstrapping proof of Stack has a very interesting characteristic it has very fast confirmation by very slow and bonding right very strong bonding and then bonding is 21 days in the cosmic Zone and uh and that's because of something called long range attack yep

and basically using Babylon with Bitcoin security you can solve the long-range attack and that sort of connects to what I said earlier is that Bitcoin is uh good on a long time scale not good in a short time scale so it's in fact a very good complement to approve a stick chain because proof of stake chain is very good in a fast time scale because it does fast finality but in a long time scale it has this long-range attacks and so they're very good complement to each other so that was the first use case bootstrapping is another use case a third use case is for example you can imagine if you want to protect some important transactions then maybe just finality on the proof of section is not enough you want to wait until the

timestamp becomes sufficiently deep onto Bitcoin and then you confirm so then you can have some differentiated service so those are the use cases that we've been exploring yeah now I'm winning if you're going to enable the first you know 35 block deep reorg of Bitcoin because someone wants to do something else on a proof of steak chain you know anyway quite expensive yeah to say the least so you're doing both your co-found you've co-handed this company but you're also still a professor at Stanford I guess so what kind of topics do you focus on today yeah so I'll be on leave from Stanford yeah so in some sense a lot of my research right now is kind of focused around this idea of sort of how do you leverage off

sort of different blockchain characteristics to get security for example here's a research problem we're looking at not necessarily tied to Babylon but sort of motivated from Babylon is okay I talk about checkpoint of Bitcoin right but maybe you can checkpoint to multiple chains why only one chain maybe you can check on the Bitcoin and ethereum and and cardano right yeah and you can say that hey maybe as long as the majority of them are secure then your protocol should be good so that's kind of a research problem that we're working on right now uh sort of motivated from sort of this idea of borrowing security from other changes do you have your own consensus as well are you using tendermint

yourself under the hood okay so again right the research is about sort of combining sort of off-the-shelf protocol yeah so therefore we're not inventing any new component Bitcoin is Bitcoin 10 minutes tenement so we're just trying to integrate them in sort of a meaningful manner to get the full Security benefits of both very cool well congratulations on the move the switch from Academia this is the first time you found the first time yeah cool you're kind of already Vaguely Familiar with the the you know how the whole Spiel goes you went to work for Qualcomm for a bit oh I think this is probably going to be slightly longer yeah so in the early days in Wireless often times is done by bigger companies yeah right

right so to impact industry you kind of have to work with them it sounds like we'll be seeing you around the cosmos events too that's cool yeah that's the world that I've been spending time in validator CK validator um but very cool thank you so much for sharing with us your kind of journey through all of these different fields bringing you to blockchain like helping you understand Bitcoin bringing you maybe into like non-bitcoin ecosystems like Cosmos and building your own

company this is amazing yeah cool it's so fun talking to you guys yeah really thank you yeah I hope it's not I hope I wasn't too long-winded in this uh no describing this I think the way I think of it is the audience has now been introduced and I think we'll we'd love to continue our conversations when we have topics that would be of interest to you possible interest thank you thanks again so I want to say thank you to the ZK podcast team Tanya Rachel and Henrik and to our listeners thanks for listening foreign