Cross-Chain Without Bridges: Secure Interoperability with Threshold Signatures

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1. 0:08

   all right thank you for the intro um hey everyone my name is Kendall and I'm there we go I am going to tell you a little bit about a world that I hope we all eventually live in which is cross chain without Bridges and we'll talk about why so uh this probably is not news to anybody in this particular the room by Crossing defi is becoming increasingly important um certainly helps we we're in

2. 0:36

   a positive Market uh but nonetheless Bridge volume since November has increased pretty substantially uh on average I'd say it's pretty close to 3 or 4X and we've also seen cross chain swap volumes increasing dramatically as well in a pretty similar fashion uh I think based on you know where it seems like things are going this is only going to increase and as great as this is one

3. 1:00

   of the issues is that we are mainly using Bridges to enable these Crossing patterns and they have a lot of limitations I think they're really not enough of the key piece of this kind of chain of traction stack to actually enable the use cases we're looking for uh so why is that well the first reason as many of you have seen time and time again is that bridges are really hardly built um the fact that they've been hacked is not because they're built by

4. 1:24

   uh you know people who don't know what they're doing they're built by some really fantastic teams who are extremely talented there's just a really large large attack surface for Building Bridges it's just it's difficult and that's why we see even some of the best teams having ex points uh the other really big issue is that a lot of chains you can't build Bridges to you cannot build bind directional Bridges to chains that don't have Smart contracts without using some pretty wonky design patterns

5. 1:48

   um and even in the smart contract chains that we do have there really aren't any bridges that go to every single chain so what this means is that users are forced to use different Bridges to go between different chains which leads to really inconsistent ux so if you use different Bridges what that means is you're going to deal with very very different bridging speeds um you know best case scenario you're looking at like Pi seconds to minutes uh worst case

6. 2:11

   scenario you're looking at hours and if you're using kind of native Bridges to some of the optimistic rollups you even be looking at day so like a full week the other issue is that each of these Bridge standards tends to introduce its own version of an asset uh what this means is that if you use one Bridge you'll end up with one version of the same asset if you use a different you'll end up with a different version which means that you might end up with the wrong version of the asset that you're

7. 2:34

   actually trying to use and you go try to swap this and realize oh there's not much liquidity for the bridge version of the asset that you have so now you have to try to get to the other version of the asset which is just a really painful experience and there's not very many good Solutions with Bridges and then the final you know not so great part of ux is having to deal with gas tokens and all the different chains that you were interacting many Bridge providers are now trying to provide solutions for this and like there are some pretty good

8. 2:59

   approach es but it's uh overall just a very very inconsistent and frustrating experience not very good if you're looking to abstract with the change so fortunately I think we do have a really interesting new addition to the kind of options and tool tool kits that developers can take advantage of in the form of programmable NPC so many of you are probably familiar with using uh NPC wallets coinbase wallet recently added

9. 3:23

   uh this kind of solution to their their um their stack uh fire blocks or a lot of the kind of uh more institutional facing products I've been using this for a while um but what we're introducing and what fortunately several other teams are also introducing and noticing is that you can actually use NPC as a core building block make it programmable give access to developers to actually kind of determine when or where to sort of issue these signatures and then even

10. 3:48

    decentralize the uh the sort of uh key shares that these different uh NPC nodes are operating and create some really robust systems so there's two main kind of approaches the programmable NPC thus far uh the most common that we've seen that's been in production for for a minute now is what I call deposit based this is basically using NPC at the chain level to create kind of deposit addresses and then they essentially have like a native rap version of an asset uh you can probably even add apple on here

11. 4:19

    as one of these examples but definity has been doing this to have kind of like Bitcoin on definity and ethereum on definity using what they call Chin key uh signatures we've seen some swap protocols like like Thor chain and chain flip and then even some like pure Bridges like axar um I think what's really interesting is the other approach uh that Us in the near community and also the lit protocol team been taking which is actually allowing each user account to use this programmable NPC to then maintain their own directly

12. 4:49

    maintain their own sub accounts on any number of chains and when it gets this gets really interesting is when you think that that can actually those accounts can also be smart contracts and this opens up an entirely new design space so what are some of the key advantages of pro programmable NPC one of the main ones is that you can actually support every single chain pretty much as long as you can support the uh the elliptic curve that the the chain is using and you can actually

13. 5:13

    design an API that's flexible enough to basically support smart contract chains nons smart contract chains whatever people are essentially building you also get instant support for new chains as long as again you support if they're ecdsa chain as long as you support ecsa uh or whatever it is that they that they have support for out of the box developers can immediately start building this they don't need to wait for you as like the bridge team to go and deploy a smart contract or like

14. 5:37

    deploy some kind of integration with that shad and since we seen to watches pretty much daily or even hourly now this is actually pretty important um and the final benefit that I think is is potentially easily overlooked is that you can really standardize the user and the developer experience with this um and what I mean is that in previous example we talked about having to use different Bridges maybe one takes an hour maybe one takes a day maybe one Tak

15. 6:00

    a week with this the the BR the cross chain interactions will take the same amount of time um and I think that's that's how we get the true change abstraction is so that you don't actually notice that your experience changed radically when you're moving between chains uh obviously there are some things you can't get around there different confirmation types and things like that but where we can abstract way that experience I think it's quite key to get to the uxv design uh so we'll

16. 6:23

    dive a little bit more into what exactly we're building in here and why we think it's it's really compellent version of for uh so you might have seen IL use this same slide earlier so basically what we are doing is launching a product called chain signatures is essentially threshold signatures that are controlled by near accounts and this can include smart contracts um so it's going to be a really really simple API it basically

17. 6:46

    just takes in a payload this payload will be the the raw transaction that you're trying to sign which can be for whichever chain um and then we'll take in kind of like a you've used like an HD wallet or or leder You' seen you can pass in like a different path and kind of generate different end accounts this means that these users can then maintain like sort of uh a many different versions of their account so they can sign for sort of different different

18. 7:11

    addresses ially uh and then finally you can pass in the key type so if you're trying to use ethereum it's ecdsa if you're trying to use salana cnano near Etc EV ed25519 and you know as we continue to add more key types you'll be able to pass those same so to walk through a little bit of an example here you have account which initiates a signature they'll include that path include the payload like the transaction they're trying to sign and they'll

19. 7:36

    essentially after they initiate the signature the NC will pick it up they'll each sign with their uh respective key Shard uh the sign is payload and they'll really will'll pass back that sign transaction to the user or the front end and then that'll end up being relayed to the destination Network so you can see here you can sign for use this in your account to sign for any basically account uh blockchain that's Sun uh and so we walk through a different example

20. 8:02

    that uses a product we're also launching called the multi-chain gas relayer similar type of setup except this time the uh NBC noes will actually kind of pass the signed transaction or at least make it available to uh a network of Rel layers will then take payment from you in some token on the near side uh a great example this could be sweat uh as ol like demonstrated earlier or usdc if you want something that's you know completely not volatile and then they'll

21. 8:28

    actually these Rel layers will be to fund the destination account with some gas tokens kind of just in time and then you'll be able to send your sign payload kind of right behind it which in some cases could even be in the same block so that if you were just sitting there with usdc but you're paying for transactions in Bitcoin and ethereum and tokens in atom in whatever it is uh so most importantly what are the different use

22. 8:51

    cases um so I think there's quite a few here because it is a very broad design space uh and I'm really excited to see what Developers come up with as they get access to this some of the areas we're particularly excited about uh not surprisingly as we talk about crossing without Bridges I think like being able to build these def5 applications that are span across different chains without needing Bridges is really powerful uh

23. 9:14

    maybe equally or even more exciting is the ability to build def applications for nons smart contract chains like Bitcoin the reason this works is that for the most part the key building block of uh of defi is accounts that are programmable and have some kind of rules they follow to determine when to basically send assets to One account or send assets to another account um and so

24. 9:38

    because we have can have Smart contracts on near that can be immutable not have any sort of way to change these contract so they are safe def5 protocols and they can sign transactions using these chain signatures on safe Bitcoin and the the smart contract can actually maintain basically the state of the defi application for the these kind of Bitcoin applications uh and we'll actually walk through an example uh of that in just a second and then uh one of the other areas that's you know I think quite powerful uh and and is going to

25. 10:09

    get a lot of attention it's kind of multi-chain account abstraction which uh will that's actually a pretty good example of what sweatsh that's basically multi chain the contraction and we'll be showing a lot more of those in the future uh so zooming in a little bit more on kind of the bridges Crossing defi just to give you guys some ideas of what it is we're looking into uh native swaps we think are going to be quite important you know you can go basically

26. 10:33

    from any asset on any chain to any asset on any other chain that's like Bitcoin e xrb salana whatever it might be um one of my personal favorite cases is building cross-chain lending basically allowing users to use any asset on any chain this can even include assets in unique states like you could have actually like distinct you could basically have statea state whatever it is um using like kind of a a specific state of asset and using that as collateral on an orderbook and then you

27. 11:02

    can borrow usdc against it uh so truly cross chain lending is going to be pretty cool and then yeah something like restating any asset on any chain where you can actually manage kind of like the slashing conditions on the near chain and then you know essentially determine who to send the asset that you have slashed on whichever chain to which could even be like a burn address so that's and then finally we'll actually walk through this example of how you can build a Bitcoin ORD Marketplace in a

28. 11:27

    trustless way so to really paint this picture for you let's imagine that we have a seller of an ordinal a buyer of this ordinal and we'll actually use usdc since there's not really any marketplaces yet that you can use thec for and then we're going to have this Marketplace contract and this Marketplace contract is basically a near account a smart contract your account it's living on the new chain so the first step here is the seller can basically ask the marketplace contract to generate a Bitcoin account that only

29. 11:53

    the marketplace contract actually controls um next step is the buyer can basically deposit usdc to this account on the near side so now they account basically both of them are kind of like funded the seller can deposit this ordinal into this Bitcoin account that's controlled by the smart contract uh so this interaction causing the oral that's happening on the Bitcoin blockchain um what's cool now is that the seller at any time can ask the marketplace

30. 12:18

    contract if it can withdraw ordinal as long as the ordinal is not an anactive order uh and the reason this is important is that uh this prohibits the seller from basically V controlling a potential buyer if they have an open order they can't just go and good drive because they don't control the account they have to ask the marketplace contract to allow them to withraw so let's say they want to go ahead and list it for 10 years to see

31. 12:41

    and the buyer comes along and sees that and they're like okay great 10 years to see is is a good deal for this ordinal basically then what happens is uh before only the seller can ask the marketplace contract to withdraw the uh the ordinal now that light transfers to the buyer so the buyer can now ask this spway contract to send that ordinal to it some Bitcoin account that they control uh and then on the the seller side the seller

32. 13:07

    now can withdraw that 10 years to see that the buyer had dep posi so this is how we can build using these uh these chain signatures This truly trustless or at least trust minimized ordinal contract but you can extend this pattern to a lot of different chains and especially these non-smart contract chains even like Ripple or Doge or bit tensor for uh for any M into that so there a very very like bload design

33. 13:30

    space here that we're pretty excited about um yeah and so we just uh the team just got some developer docs out there's a lot of examples there so on the I guess left here you have the developer docs so go try those out give us feedback we'll see what you can build and then if you want to join the telegram group we have like a de chat with all the relevant people in there uh who can answer questions and a lot of

34. 13:52

    folks have enjoyed that and yeah that's what I have for you guys so thanks everyone