 Thanks so much. Welcome. This will be a deep dive or more like a snorkeling. We will now look a bit under the hood, but this morning we were focusing on the user side and now we will look a bit more on the developer side and a little bit under the hood. So Wallace is set up as a GitHub organization and it has several like a modularity. It has several repositories. One is the Wallace, that's the app basically. Ketherium is a library, a Kotlin, this is all you see Kotlin libraries, a Kotlin Ethereum library that I use in Wallace and also in Wallace push. Other apps, that's the website, so if you find a typo that's where you can correct that. There might be some. K-Hex for extension functions for hexadecimal stuff and K-Cock for the hashes. You need that all the time. You saw a lot of Kotlin. Like now I have to describe why did I use Kotlin and it is basically because Kotlin is an awesome language. It makes you a happy and more productive programmer. Who in this room knows Kotlin? Like I have to get the audience with, oh, that's way too little. Yeah. So Kotlin is a language from JetBrains and JetBrains, a lot of people of you might already know because they are providing an IDE. Many of you developers might already use it. IntelliJ IDEA and IntelliJ IDEA is basically the base for a lot of IDEs out there. They are really good. And Kotlin, you see how nice that fits from the logos? It fits really well. And what you see also here, it gets really traction. It's a quite new language. But you see it gets traction. It's going up here and you see other languages like this closure thingies going down. For example, there are other clients implemented in closure and it's going down. Kotlin is going up. That's really good. And here you also see why. Because at this year's Google I.O., Google made it official. It's now an official language for Android. And before, like I'm doing Kotlin way longer than Google was announcing it. But before it was always big companies were like, ooh, we cannot use it because Google might decide to fight against it. But since Google made it official, you see the adoption got really high. That's where we are now. And I'm attending a lot of Android conferences. And now it's more and more talks about Kotlin, Kotlin, Kotlin, Kotlin is everywhere. And it's a really nice concise language. And the nice thing is it compiles to Java and Java six byte code. And that's basically why I can use it for Android development. And that's really nice. But it's also nice because it also can compile to JavaScript. That's quite new and quite unstable yet. But it's going there. And also to Kotlin native. So that means embedded machines. And so in the future, you can also use it for that. And then it's quite fast. So but I'm just using the Java part now. But in the future, we might use it for, so like we have type safety, you know, JavaScript, no type safety, bad, bad, really, really bad. So Ketherium. So I was, I like to like then write a library there. And it doesn't contain much now, but it's all that I'm using that all in Walluth. And that could be building blocks to in the end, because that's my end vision to also have an official implementation of Ethereum in Kotlin. But it's way off. But now it's like collecting all the building blocks. And then that gets easier, because if all the building blocks are already there, you just have to connect them. Basically, it's easy, right? So but I can't do that alone. So that's also why I'm here. But advertisement, if you want to join, it's all open source pull requests welcome. So there's already our P encoding, and basically also using that for treasure support in, in Walluth. There is BIP 44, also for the treasure support. You see 55 address checks sums are in there, or nice with tests and stuff. You see 67 URLs, you see 67 again, very important. Don't use plain addresses use your C 67 or the new standard that is emerging. Find more information on wallet.org. There's a block. It already contains some crypto stuff. Hash functions, Kekak use Kekak all over the place in Ethereum. And basically models you can use over a lot of projects. Because this way, we can share code because as good programmers, we want to write dry code. Don't repeat yourself, right? We don't want to use wet code, which is like wet is nice in the ocean, but wet is bad in code, you know? So, Ethereum is used by Walluth, then also issueth, that's another project that is in the context of Walluth. I will talk about that a little bit later. Then also Walluth FCM is fire-based cloud messaging, unfortunately some centralized shit. But for now, sometimes you have to make small steps. You know, you cannot do everything full decentralization. You have to make some shortcuts. That's a shortcut now. In the end, I really love what status is doing there with the decentralized push, but unfortunately it's not yet there. But I hope for the future there. And then it's also used by Hamdall Android. That's a project of Knosis. It's basically a multi-signature wallet. So, and I invite you to also use Ketherium in your projects, try it out, send feedback, extend it, use it, and so on. And then we built the pyramid even higher. Who has attended the talk this morning? Not that many, but there will be a video. Please watch the video because I can't go into details much there because I love to build with building blocks. You know, we need building blocks, small steps, and basically also Walluth then is a building block for another project of mine, Pass Android, S-Pass, basically a ticket system on top of Walluth because not every app should have their own light client because light clients are really, really heavy. And if you have that in all apps, then your phone has no memory anymore. It's bad. And we want that for emerging markets. And they have really, really small devices. And another app of mine, I was writing Satoshi Proof. It's a Bitcoin proof of existence system. And I want to adapt that to Ethereum because that fits way nicer because at the moment on Bitcoin, I'm sending like Satoshi's to addresses that don't really exist. And that is the proof basically. And Bitcoin people don't really like that because I'm burning money. I like burning money. But it's bad. Bitcoin people don't like it. But for Ethereum, it would be much nicer because you can just write the timestamps as data on the chain. And you can get that all via Jetpack. Jetpack is a really nice project to basically get the artifacts for code. And I just have to basically push a tag to GitHub. And then Jetpack is already available on Jetpack. Not like with Maven Central. I have to upload it. So Jetpack is really nice for that. There is one problem, though, trust. We are in a security thing here. And if you just trust the artifacts that are coming from Jetpack, bad because they could basically give you an artifact that is malicious and that could steal your keys. And I was very clear in the morning we need open stuff and the keys have to be protected. So there's one nice thing from Whisper Systems. Whisper Systems is basically the foundation behind Signal. And that's Gradle Witness. And basically that proves that the artifacts, by the hash of the artifacts, that these are the right hashes. And you always have to prove, basically, that the artifacts are right. So I'm using Gradle Witness. Don't just use it via Jetpack and trust it. Use Gradle Witness and pin your artifacts. And you should also, I see that often in the human space, they use stuff from NPM and everywhere that's centralized and that could give you malicious artifacts. So really be careful. And I don't know if something for NPM is existing like that. But you should because otherwise, wow, it's crude. I want to talk shortly about issue F. Perhaps you have heard about commit status. Also a really nice project. And I basically got the idea from that. But I couldn't really use it because it basically wants admin permission for my GitHub. And my GitHub is holy for me. So I didn't want to give them admin permission. And at this year's GitHub satellite, they were basically introducing GitHub apps that are tight integrations into GitHub. And with that, you can really have fine grained permissions. And I don't only have to give permissions to reading and writing issues on my repository. So it can't do anything else. It can't do anything with my code. So that's really nice. So I started issue F for that. And that's a little bit about tokens. I don't want to introduce tokens in my app because I love my users. I want and I think when I introduce like that was a picture of posting once. I added tokens to our apps. Great. Now we have a lot of money. But it's not less user friendly. Don't worry. They will love the tokens. But they will not because it's just annoying. I don't want tokens in my app. But for issue, it's quite nice. You just install it in your GitHub repository basically. And then the committed like admin access. Wow, bad. But I heard I fixed it now, but I tried. It was not yet fixed. But that's a problem. I opened the issue there. On issues, you just you can go to your GitHub repository, press install here. And then basically you can also only do it for some repositories until it's only read access to metadata, read and write to issues. That's not that intrusive, right? And then what you just do, you add a bounty label to your issue. And then it's adding this nice ERC 67 QR code there. And then for example, you could scan it with wallet and transfer value to that. And then it looks like that. New token transfer on Ringaby with a value of 1.1 wall. 1.1 wall is basically the wallet's tokens. They are not worth anything yet. But it's the same with a lot of other tokens. They are not really worth anything. So, but I will give it to you for like fixing issues or opening issues or even just attending. If you approach me, like you get basic attention tokens, you know, you visit my talks. So come to me, I give you some tokens, install the app. They're not yet worth. And they're also on Ringaby only. Like why waste money on mainnet. Ringaby is nice, right? And then if you close the issue basically, then I sign, like I encrypt the private key for the account for, like I can read the PGP key for the one who's assigned to this issue. And I encrypt it for him. He can decrypt it and send the money anywhere that has the really nice advantage that I don't have to spend money in transfer fees. He can do it if he wants. If he doesn't trust me, he transfers it directly. Or if he trusts me, he can even leave that. I don't really care. But just I don't want to pay any transfer fees because I like being without money. So, and I hope that changes the situation a bit because that's the current participation of Walluth and it's mainly me. But some other nice contributors and thanks to you all. And I wanted to say like this morning, I had to really rush through the presentation because I was a bit late there. But thanks to all the contributors and I hope there will be more contributors in the future. And you all get wall tokens. Wall tokens are nice. Like even bragging rights, you know? You have wall tokens. Really cool. I also want to say I'm using the new Android architecture components in Wallet. They are really nice. They were also introduced with this year's Google I.O. I really like them. I use a room for that, room database to store all the addresses, to store like everything because it has a really, really nice interface. And you just annotate some DAO methods with your SQL queries and you can access that stuff really, really easily. It's not yet a release version. It's a release candidate now. But the same, like Walluth is still alpha. So, when Walluth gets in beta, they will have it released, I think. But it's a really, really nice library. And also, like, use live data from there and all the architecture components. Really, really nice. Like the Android team really kicks us. Android is nice. Apple is shit. Close source. Android, open source. Nice. That's really dark. That's really bad. These are services that are in Walluth. That's the get age. I'm using Go Ethereum. The Go Ethereum team also nice at the moment using Go Ethereum for most of the consensus stuff. In the end, I also want to replace it with a real Kotlin implementation because that would be even smaller at the moment. Walluth is quite big because I have to compile it for all the architectures. But I love the Go team. They are really, really good. And I don't want to care for that at the moment because I'm more like, I want to have nice user interfaces and stuff like that. That's really dark. That's really bad. Yeah, these are product flavors basically. So, it's for asteroid. You find the app on asteroid. And for Amazon, I haven't yet released it. Releasing on Amazon is a real pain in the ass. But I wanted to do it later. When Walluth isn't better, I will also release it. These are flavors for Amazon. For Google Play, I compile Firebase in there. Firebase is close source. Bad. But on Google, you're fucked anyway. But for example then on asteroid, I don't compile Firebase in there. Then you don't have push messages. I have to finish now. Android Things. Approach me with that. I'm doing some experiments with Android Things. It's really nice working and consensus. This is my URL, Legity, Walluth.org. Let's pass. Have a nice day.