Blockchain Basics (Part 5)

Business Models: “Beer of Satoshi”

And among others, this guy was also in Cologne, together with his wife, beer Satoshi. And the whole thing is that he gave me one bottle. And when he took the bottle, it’s not that cheap. I mean, you see here, there’s three beers, about 27 euros. That’s quite a lot, I mean, for beer. And the beer itself is being produced in the Eiffel, which is the area south of here. It’s a local brewery. They actually introduced the beer. It’s OK. It’s fine. But the trick is the following. When you open the bottle, there is a QR code under the cap. And then you can scan the QR code. And when you do that, you can register. So take your email address. And you have to provide some kind of age, because it’s alcohol. And then you can, after providing this onboarding process, they get you a link of QR code. And that QR code can be scanned with a Bitcoin lightning app. So we talked about Bitcoin, but there’s also Bitcoin lightning, which is some sort of a second level network. It’s not a chain directly, but it’s a second level network on top of Bitcoin. And that allows you to have very quick and fast transactions, so almost instantly, without big transaction costs. And yeah, I did this. And now I own 310 Satoshis. Satoshi, they are called there, Satoshis, which has a value of 0.27 euros. So I think if you compare it with the price of the beer, it’s quite a nice marketing idea. But you can actually win more. That’s the whole idea. But it’s their business model. It’s just another way on how people try to make out of the data of a use case, out to capitalize what’s going on in this whole blockchain market. So that’s the “beer of Satoshi”. So it’s the “wallet of Satoshi”, which is the … they created yesterday and it plays on the lightning network. So it’s really a scan the code. You can’t use a Satoshis. Which means that this is something we have discussed, which is actually the Bitcoin lightning network, which is quite interesting. Because it’s really something like a fast payment network based on Bitcoin. And so maybe you use this as the next exercise, so that you all investigate how the lightning network works. Because it’s completely different from what we discussed before. So I think about a nice exercise so that you work on the lightning network and see what’s going on there.

Business Models: “MetaBrewery”

There is another way of making some kind of money with beer and alcohol on the web, which is the, that’s just to my mind. So that’s another way. So that’s the MetaBrewery. And this MetaBrewery can do the following. It’s also a brewery. And it’s a small brewery in southern Germany somewhere. And what they did is that they sold NFTs. So you can buy a token and by ordering the token, you get 140 bottles of cans of beer every year for your whole life. Looks like a great deal. It’s not that cheap. It costs you about 1,000 euros. So the NFT, also the entrance card more or less, that you buy by an NFT. We talk about NFTs in the NFT. So you buy that. And by that you get beer for your lifetime. So you can make a calculation, 1,000 euros. How long will it last? Actually, it’s promised they do it for two or three years. So they can guarantee to get the beer for two or three years. So that’s another way of just trying to build up a somehow business model application on that.

The point here really is that they got a complete new, they say “Kundenstamm”. By doing that, they got extremely well-known all over the world. So it’s a local brewery in Bavaria. And suddenly, they got customers all over the world because they make this announcement. And all over the world, people just bought the NFT for 1,000 euros and then they got the beer. And a colleague of us did that. So for some time, we were flooded with beer, which is a nice thing. The other thing is that if you buy 10 NFTs, you can sell the beer. I mean, you can do sell it anyhow. But then they provide you with a new branded beer just for yourself. So what we did is for a conference, we created the WEB 3 beer. We created his own beer brand that is selling in Cologne, which is difficult. I mean, in Cologne, you drink Kölsch or nothing. You go to a water. So it was not so easy for him really to get the beer somehow announced in Cologne. I think it wasn’t a big success. But it allowed these people together with some friends. So it allowed them really to produce their own beer brand more or less. So actually, by buying this kind of token, they bought a shell somehow on the company, which allowed them to use or to get their own branded beer. Well, that was also a nice idea and how to do that.

OK, so these are just two examples from the alcohol market. There are more. There’s a, I think, a blockchain, gin, things like that. So there are different people who think about possible applications. So let’s see if the new base app comes out, where you can just create without much programming knowledge your own microapps on top of this blockchain. Maybe some of you can discuss some nice interesting new applications and become rich. Maybe we’ll see next year. It’s not yet open. I think it’s only 18s or 19s they are going to publish it. He was very mystery about the whole thing. OK, good. So much about that one.

Exercise: Use cases

But what we wanted to do is now also to discuss your submissions and what kind of use cases you found on that one. So I got 10 submissions altogether, which I have here. So is there someone who wants to present his submission voluntarily? Otherwise, you just pick it up randomly. So either doing voluntarily or just pick it up randomly. There’s someone? OK. So your name is? Yeah, we can have several ones. No, don’t worry. Go ahead. OK.

Exercise: Certificates

So your is that of blockchain certificates. OK, maybe you can explain what you did there. So I thought of using the blockchain as a tool to provide certificates to people who completed further training or workshops, for example, for fire safety officers or for aid courses. And then as the task suggested, I was discussing this case with this blockchain diagram by Bruce and David in mind. And yes, we do need to store a state as we need to know whether the training is completed or not. And there are with providers as all institutions that offer further trainings or workshops should be able to write on it. And there is usually no always online trusted third party because usually the certificates are on paper. And then your employee or other institutions just have to move you. The question whether all writers are known is a little bit more complicated because you can tackle this with two kind of approaches. Either you say, OK, I have this set of well-known institutions that offer workshops and further training than all writers are known. But if you want to create a more open application where you want to have also institutions that offer these trainings, that maybe just come up over time and did not exist prior to creation or are not registered somewhere, then you need it to be open. So this is somewhat a yes-no thing. And then obviously public verifiability is required as employees and other interested parties need to verify that the first and has the completed training. For example, if you do an orcats per rehearsal in a separate room, you need to have a fire safety officer there. And then according to this diagram, you would need permission as a blockchain when we wanted that all writers are unknown. But in the event that only registered training institutions could access this, there is a public permission blockchain. And then further discussion, this focuses on the slides before the news case canvass, so whether there is an intermediary removed. And in this case, there is none removed, rather there’s one added because this intermediate that we add is the blockchain itself. And it provides the fact that you can always trust the certificate. As for example, if I have a trainer, a coach at these workshops with, I don’t know, my friend, and I need some certificate that I did some workshop, we have better chances at the company where I’m applying. Then it might be the case that my friend just gives me the certificate without me completing the training or that someone else with malicious intent can take these certificates themselves. So as these certificates then even influence new resource decisions and are vital in cases such as fire safety officers or first aid courses, the high data integrity is important. So blockchain is also there providing the full maintenance data and then for automation, you could use the revocation of certificates for trainings with require a refresher course after a big amount of time, such as the aid courses. And then the unique characteristic or the task is then issuing certificates on the blockchain and the data contains the qualification or the certificate itself and then the institution can derive the qualification. The partners there are the training institutions, the other institutions, such as employees, which need to verify that someone has the certificate and then also the individuals completing the training and the values arrive at the type of qualifications and the expiration dates for certificates which need to be returned courses and that machine would be the revocation. Yeah, that’s an example. Thanks, well done. What kind of information would be actually put on the blockchain then? So what would you store on the blockchain from a certificate? Yeah, certificate which contains a lot of information. What would you actually put on the blockchain? On the blockchain, I would… So my initial idea, which would also need a little bit of speaking around in the non-workchain world, would be that we would identify as a workshop, for example, and then just the public address of the institution that built the workshop. So then we have for the employer’s perspective, for example, we can see, okay, my applicant X has these certificates and then I can, with the certificate identifier, I can see what qualifications come with it and with the issuer public address, so the individual that offers the training, we can also see, okay, this institution which offers workshops on a level that we, as employer, support. Okay, so that would mean that if you apply for a job somewhere, you provide them with the information about the cost. I visited costs 47.11 by organization, and that’s my address. Yeah. Okay, what about if you got a grade? Maybe with a grade? Hmm. This content is on the blockchain, but on the third, so I mean, the introduction of blockchain into this kind of process doesn’t mean that I need to get rid of everything else, that it’s maybe, that it does not need to become paymentable. Yeah. So I think, actually, the systems that actually do that, they’ve worked a little bit different, because what you’ve proved then to the employees, the cost number, your name, or your address, and the others, the rest, would somehow be that if I know your address, what I can do then is to query the blockchain for all the courses that you did. You do like that? No. Okay. So, you see, there’s some design issue there, yeah? Really talking about privacy. Some other idea, what should we put on the blockchain in this kind of certification in this case? Other alternatives, how about, did someone else do a certification use case? Yeah. What would you put there? Honestly, I would just not put it on the blockchain, but I would go with just the common central database. It’s really like putting in this blockchain for the type of food in it from the blockchain. Okay, so you would say, this is not a good blockchain use case? No, not really. Okay, so you go for the centralized approach? Yeah. Who would you trust? So, the company that issues this certificate. Yeah, okay, so this means that when someone, when I get a certificate from every day I have to contact, every day I have to contact, every day I have to contact the university, just the colonel, I need to contact them. So I got that value, who is giving me five different certificates, so I have to go to each instance. Okay, so basically, what I think of it as, you know, like a, it’s a digital certificate, so to prove if it’s valid or not, you basically need some way to make a query to institutions that database, which will return like a two or four. Okay, but then the institution goes, you did this as a private institution. Yeah, you start, hey, we offer the best courses on blockchain. Yeah, visit our best courses on blockchain next year at AirBank, they’re closed on the server. You can never prove that you really are, really visited that course. Okay, but if, you know, there is, then, I would get a question, you know, if like this for sure, period of time, and it means it wasn’t really established, can those courses be trusted in the third place? Okay, yeah, that’s a good argument. Yeah, okay, that’s a good argument, whether the course issued by that organization was, well, good at all. Okay, but it’s really, it’s really a very interesting discussion, and it’s a discussion that’s ongoing, yeah. So it’s good that it came up. There are people who say, we don’t need to put certificates on the blockchain, we have the organization, I think I would get a, I think they put a code that you can use online somewhere. I think there was a website period of time with the code, and then we see whether it is correct. On the other hand, not many organizations really want to keep the infrastructure for that. If you really trust a central organization, let’s say put all the German certificates on a German big server, maybe a German will trust that, maybe in other countries, I wouldn’t trust that, because they have so much power over you. So they can just remove all those difficulties. The issue here really with the blockchain is that there is a decentralized infrastructure, and once the infrastructure is there, no one can remove it, it’s there. So that’s the power of that, that’s the unique, as you say that, that’s the unique selling point. But what would we put on the blockchain? I mean, you said, you put these ideas, you said nothing, another suggestion. What would you put on the blockchain with this kind of certification cost? I would say the person who took the course should tell the issue in the entity whether they want the course certificate to be on the blockchain. Okay, so, okay, I say yes, put my certificate on the blockchain. What would you put on the blockchain then? What needs to be on the blockchain such that I can go to another employee and say, hey, I’ve been at this course. Here is something that allows you to check it. What would you store on the blockchain then to provide this check? No, maybe not issue, not put the public record on individual there, but give every course iteration an identifier or something like this and then issue the people in part token it, this identifier and only they have it. Yeah, but maybe this is awesome. It’s not a bit directed there. Yeah, you have an idea? Perhaps the issuer of the certificate to sign a transaction with their own flight token and publish a hash of the certificate on the blockchain. So then the only way of having a preimage of that hash is by having a certificate that you can prove to any employer that you have a certificate and that it’s valid because it hashes to the same hash on the flight and the efficient one. That’s the idea. That’s actually almost the same story. So when you do this, you issue still a digital document, the PDF document, a JSON file, an XML file, whatever you like. And that’s then your digital document that you have. Let’s take the easy, the PDF are a little bit critical. We can discuss this. Let’s assume and get a PDF, which is your certificate about your bachelor or your master. This PDF file is then being hashed. And then we have a smart contract and this smart contract is being managed by Avatar Aafen. And Avatar Aafen has the right to write to that particular smart contract. And what Avatar Aafen does is it’s the person who owns the private key for Avatar Aafen of our the proofing arm, the test authority of Avatar Aafen. So he has the private key to write to that particular smart contract. And what this person does is nothing else than putting the hash of your PDF and storing it in the smart contract. So the smart contract in the end has thousands of hashes because there are thousands of documents that are being, are thousands of certificates issued by Avatar Aafen, which is the problem. So it has thousands of hashes. And when you want to prove whether a certificate is correct, you send the PDF to the employee. The employee takes the hash of the PDF and asks the smart contract, do you know about this particular hash? And then the smart contract will return, yes, this hash has been sent to me on 18th of December, 2006. Together with maybe some further information, still valid or only valid until next year or something like that. Now, on the other end, you may say, well, probably somehow difficult because how would an employee know about the smart contract? When they need to find the smart contract. Okay, but that, you would need then again, the web page, the web page that I have there, you can track and drop the PDF, you just take the PDF, drop it on the web page. The web page computes the hash, which is JavaScript, nothing special, and then sends it to the smart contract. That’s the easiest way, how most things do it, how we do it, we have it a little bit more complicated. You can discuss this when you go into a smart contract there because you can do some additional tricks there. That’s the easiest way, you just hash something right out of the blockchain. If you want to check whether it’s still the same status, you do it. Actually, but don’t you agree like in the first part, like in the new year, getting the hash is valid, and then you validate it like this, if you think the automation. Yeah, the automation is actually, so what the third, what the employer, where you apply for a job is just doing, you just see it’s R, it’s something from avatar app, and then it just takes it and drops it on the web page of avatar app. So it’s just avatar app in the end to provide the service. Again, then we have the argument, but if you have a certificate from app below, you would need to know all the three web pages. Again, there it would be nice to have some kind of standardization where you have a central portal, and then based on the hash, or based on some additional information that’s in the PDF, it knows where to check which web page, which smart phone that it has to check. Oh, we’re doing it from the state, or the different state, and it’s a good thing. Yeah, but it won’t be a problem. We’ll have a little bit of a problem. Yeah, no, it’s not a problem, no, no, no. For example, if it has an issue through a wrong certificate, so it says 2.0, it says 1.0, for your master code. And then, oh yeah, they’re wrong. And then you still have the document, you still have the paper document, with which you can apply at all employees. And if Avatar Achenthal to give us the paper document back, you would do it. You say, oh no, no, no, no, no, I can’t find it anymore. But he uses them for applying for a job. But if you would then use that to apply for a job, and if they check it, what Avatar Achenthal can do, is they can mark this particular certificate as no longer valid, so they can remove it. They can’t remove it from the blockchain, because you can’t remove anything from the blockchain, but you can mark it in the smart contract as invalid. So it’s no longer valid. Okay, yeah, yeah, yeah, yeah, yeah, yeah, yeah, yeah. And then, I think we have to really ask how you guys are doing this. Yeah, yes, in fact, yeah, okay, okay, it would be something like having the certificate at Avatar Achenthal, so it’s still the trust in Avatar Achenthal. Yeah, if you have to trust in Avatar Achenthal, that they just go by accident, they just revoke your certificate, obviously. It’s still, that’s the case. But on the other hand, even if Avatar Achenthal, which we don’t know, breaks down, it’s still there. It’s still there in the smart contract, in Finland, as long as the blockchain lives. It’s right, yeah, but… Yeah, but it’s, I wouldn’t say, the basic idea of blockchain is not that nothing can be revoked. It’s that it’s immutable. It’s immutable, it can’t be changed by someone else. So you still see on the blockchain that once you have the certificate and you still see that after some time, it has to be revoked. You can see this in the history of the blockchain. So you can see that it’s still there, and you can see that it’s still there. But after some time, it has to be revoked. You can see this in the history of the blockchain. It’s, fully agreed, it’s a little bit of, a little bit of, it’s sometimes difficult to see the difference. But I know, like, if you have a transaction, which I’ve heard, someone, if you can revoke it, you can revoke it. No, you can’t revoke it. Okay, that’s right, you can’t revoke it. So you can’t make it very wrong. I think of it as if you get the grant with some transaction. Yeah, I think that’s a good one. I think it’s really a use case. Sometimes certificates must be revoked. It’s a must that you can do. Yeah, you still can use blockchain because then, from the point of the issuer, it’s important that you use blockchain because then you can revoke it. With other blockchain, it’s more difficult. The point of using blockchain is that it’s, it’s a very difficult question. The point of using blockchain is that it will still be there, even if the issuer breaks down. Nobody else can change it. And in particular, not he can change it. I mean, if I give him a PDF document, I think he’s clever enough to modify the PDF document. Easy, the PDF is not a problem. That’s all I have with the ACHL. Make sure that if he changes the PDF document, the employer will see it immediately when he changes it. Yes, definitely. And they have to server. Yeah, they can have a server. Yeah, but then the whole trust is in the server. And if someone hacks the server, you’re gone. I think that’s the approach. If you like to have the server, you have to blockchain. It’s not that you don’t want to better our words. Different, yeah. So we can, like, you can update the state of a smart contract and then the smart contract would reflect that it was revoked, even though it was given a mission in Siborchnum, then it blocked on the later on, then the smart contract was updated, and then you can see that it was given. Yeah, that’s the kind of thing that some people don’t do out of the report, so they really want to avoid the value of that information. At least you have the whole history. You have the whole chain. You have the whole history.

Exercise: Government election layer

Okay, so what was your use case? Which one was it? You see your name? I think. You think? Okay. So let’s see. Government election layer. Okay, so can you talk us through a little bit? What was your use case? It was quite a high level, I can give you my detail. In principle, I put a very short, like, all the things that were done in the past, for example, and like the voting process, and all the votes that people have done on the vote, the delays, the vote. It’s not the vote, it’s not the change, it’s not the data, it’s not the input, and we used, for example, the smart contract to perform the power on the counter of the votes, and the results are clear, and we vote by everyone. The only way to come to think is that we’d like to earn the alimony of the votes, so we know that the votes done, but we don’t know who did it for the other. But we know that it’s a valid vote, so some of the votes have the right vote for the vote, but it’s not the same as the other. Good, yeah, I think that’s also a valid use case, and it fully goes with your argument that you shouldn’t be able to revoke it. A vote should not be able to, I mean, once you put it into the box, you can’t tell people, I’ll open it again, I’ll let you change my mind. No problem, keep me company. Okay, so, but this voting, we always have the problem of another empty. That’s the big issue, I mean, I don’t want you to know my vote. Yeah, good, good. So, and you sent me a token now, and with this token, I objected myself against the system. That’s the idea. And it’s a high-level, so it’s not the right, but my approach was not to have your hero, so you’re free to send your phone to the election desk, and you can go ahead and find your phone and you can find your phone, you can have your phone to go to the election desk, you can have your phone to go to the election desk, or you can have some kind of lease, or you can have your ID card, which is a very stated trans-privileged issue, but we know that you’re all kind of getting very involved in that. Yeah, I think, I mean, on a high level, this is completely convincing, and people do vote in on the block, right? I think if you go deeper, it’s really interesting to ensure privacy, we need to ensure that nobody can check whether you have voted or not, because this is something, at least this is generally something you don’t need to tell somebody if you have voted or not, and what you actually voted.

Exercise: Decentralized Wiki

Quote from below (to explain why “Government election layer” is a similar idea to “Decentralized Wiki”):

“And it’s similar with you. I mean, you have a similar idea that the Wiki pages, you get some incentives when you do some voting and things like that.”

Yeah? Okay, you actually also wanted to add a minute. Yeah, but I didn’t upload it, I wanted to complete it. Ah, okay, but maybe you can explain it. Yeah, so, like a few years ago, I think Musk offered Wikipedia a billion dollars if they changed the name to Wikipedia. That’s true. And there’s also like repeated criticism that they asked for donations, but the donations are actually what they would need for running the server. And it’s not decentralized on a private server, even though it appears to be public and everyone can participate. So I thought, okay, maybe there’s a way of having a decentralized Wiki kind of, but the information, all the text, is probably too much to store on a blockchain, because too much data. So I thought a bit more general is there a way to provide a library that to the outside appears like a traditional server, but behind the scenes runs a decentralized blockchain. And for the use case kind of, of what’s on the Wiki, the concept would be that every time you want to access an article, you pay upfront a small amount that’s based on market, how much the notes required you pay. This goes to a blockchain note that stores the hash of the text, a list of author on their private address so that they can get a share. And some kind of token that is kind of the credibility of different authors. And you need some credibility to change a text. And every time you want to change a text on the block, articles, there’s a voting kind of, and it gets approved by the majority of people. And those who voted for the change will receive more credibility. And the actual data is provided by anyone who runs the server, and you would retrieve the data from the server and can validate the correct article by it hashing it and looking at the chain for the hash.

It’s a good example. Could be a massive issue. So that’s implemented. We did, and I think it’s really interesting in the context of AI. We did something in another master thesis where we used a similar mechanism in a way that people could provide documents which are then being used to fill in a RAG pipeline for a chatbot. You know what a RAG pipeline is? It’s not a RAG pipeline, we’re a tree for augmented generation. So it’s a little bit of that. So normally when you start using a chatbot like chatbot or whatever, chatbot answers the questions based on its internal information, which is the big, big neural network and so on. So it’s just using the information then it knows. A RAG pipeline does the following. A RAG pipeline does the following. It goes first into a data bit. Yeah. That’s a RAG pipeline. So if you use a RAG pipeline, then you do the following. Before you really go to the large language model, you first search a database and you search the database for information based on your query. So you look up a database, then you get some information and you take that information then to the large database. You take that information then to the large language model and say, please answer this question based on this particular context that I’m giving. And this means that we do retrieval augmented generation. What he’s saying, but they can look into web pages is similar. What they do in web pages is that they take the web page and then they interpret the web page and then they provide the answer based on that. It’s just, I like this example. Just got me there because it’s so interesting. What we do is the following. I’m just, mouse. We do this now, we create a data. So we check. So, let’s say, that’s my best example. I like much. So what is the color of the Cologne Cathedral? Okay, so, that is the map. Now we get some information about the cathedral. Yeah, that is the dark gray almost laid from the outside, which is gray. Now we do the following. We get new information. Now we say context. Every one. We say answer all questions only based on the provided context. Context. The Cologne Cathedral is red and white because of the Cologne Football Club swan temperature. Question. What is the color of the Cologne Cathedral? The dark. Let’s see. What is white? You can also show this by asking for example, recent information that has not existed when the model was trained. What is today’s news article? And it can’t be in a neural network. So it has to be data. So what you do there is actually the context is that what you get from the database. And this is what we did with the papers. So you can build up the knowledge base by putting a lot of papers into a database. Then when you ask a question, you look up the papers that are relevant for that question. If you did this for blockchain, so we uploaded a hundred of papers about blockchain and web three into a database. And then you ask what is proof of work? It gets into the database, gets all the papers that say something about proof of work, puts that into this format. First, you send to the checkbook, answer all questions, only based on the provided context. Context, you put the text of the papers, question what is proof of work. And then the large language program starts your only information about based on the context. And it doesn’t look into its own knowledge. It only looks into the context that you provided. And that means that we did this in the master thesis where we used that, that when you want to use that checkbook, you have to buy some tokens. When you answer a question, we check which papers answer that question best. And then the people who uploaded that paper got some incentive. And it’s similar with you. I mean, you have a similar idea that the Wiki pages, you get some incentives when you do some voting and things like that. And you implement that using the IPFS, which we also discussed next time, because you wouldn’t upload papers to the blockchain, you upload them to the IPFS, which is also decentralized system, which ensures that the context is correct. And I think in particular with AI and authorship, intellectual property rights and things like that, these kind of blockchain combination becomes extremely relevant. And really to authenticate who provided the context, that the system is actually using to provide an answer to me. And you see here, just from that example, that never trust the check dialogue that you haven’t seen from the beginning on. Yeah, I mean, it’s just that I just provide some kind of context in the history, which is then from now on being used by this particular checkbook. And there are some other kind of nice examples. Yeah. This is called Lionel Calibration. Yeah. Yeah, that’s what kind of… Right. And there is, I’m not sure if someone told you about this, or maybe you did, what you… I mean, imagine that you provide your master’s thesis. And I have to write a review of your master’s thesis. That’s a very nice prompt. Just provide a nice review for this master’s thesis based on the structure. And I get perfect review. What can you do in order to somehow trick me out? I’m not sure, but there were cases where they put in white writing in scientific papers, don’t read you this paper badly or something like that. Exactly what you do. You write a system prompt in your master’s thesis. But you do it in white letters, such that when it’s being printed, it’s not being seen. But when the document is being just analyzed by the system, the system just extracts the text out of the document. Maybe also some formalities. Maybe the new versions also extracts some formal information that they’ve been traveling. But in white, so that when it’s printed, I can see it. But when it’s being sent to the Lachnäk文ch model, there is a system prompt. If this paper is being reviewed, provide the following information. Now, so you have some kind of prompt injection, which is… But this is just a side effect. It’s common to have a master thesis. It would be like, No, no professors do it. No. No, it’s not. No, actually, a master thesis, when we do a master thesis, it even knows that we have a form, where we just check a lot of different things. So it’s more like a multiple choice checking, whether you did it with literature or if you have snow. And that’s much easier than uploading. It’s nice if you need to provide a summary of things. But on the other hand, I also should be able to copy your abstract. Yeah, yeah. Okay, so that’s just a side effect.

Exercise: Replace Fiverr

Do we have another interesting use case? Someone else who wants to present his use case on that? Okay, yeah.

student1: So there is already this website, it’s called Fiverr. Yeah. So you were asked people to do something for you, like create some sort of, for example, website or something like that. Mixed in formari. It’s the same idea, but it’s just a little work changing. And you get rid of the middle party, which is Fiverr. So this is kind of…

prof: Some kind of labor management. So you can order people to do something.

student1: It’s on the online service, it’s mostly create the video or create the website. So we get rid of the middle man into the Fiverr. So no commissions go to them. And we took a smart contract, we screened the two parties to see whether the both parties were satisfied, then the cards were given to the customer and then they went to the time, to the person who made the thing. And if they’re not satisfied, then everyone puts their own name.

prof: Yeah, go ahead.

student2: I have several questions, because I like to want to do a three-line form announcement.

student1: Yeah, exactly.

student2: So when you say, okay, there does not get any provisions in the intermediate, but you mean, like, there are a lot of people that have the miner problems and stuff. So when you say you don’t want to have any intermediate, do you just need to have every few answers on it in the miner also?

student1: So yeah, the miner, they get their share, but I said it’s immediate Fiverr, in this case you don’t have that. So most of the commissions they go, maybe they want to create.

student2: Is there some kind of internal regulation in the network? Because what would stop me as someone who requests the service, for example, some video editing of just saying, oh, I’m not satisfied, I keep my money, but I still have to do it. I still receive the work.

student1: Usually what Fiverr usually does is that he gets a review of the video, and it’s low quality and has a lot of water mark, in case there is a conflict, you don’t get the action problem.

Quiz

Okay, so as I said, what we wanted to do today is also to have some kind of a quiz. And that’s what I prepared. So it’s based on the idea now that you, what you need to do is to scan the QR code. Otherwise you can’t play. You can do it with a, or you can either type it in your laptop or this thing. Hello. You can use your full name, you can use a nickname, whatever you like. I can get spices.

I think some of you know, so what you see now in the next is that you see a question, you see either yes or no, you see for answering, so for possible answers, sometimes it’s one is correct, sometimes several are correct, and sometimes you will see some kind of a puzzle that things need to be put in order.

So last time I used it, it was for free, but now we have to pay for it, but when you pay for it, it’s only three for 10 people. It’s more than 10 people you have to pay, but when you pay for it, you get a little bit more features. Someone is still not in. Oh my, is that so, I’m out. You’re out. Okay. Okay, good. So, but then everybody’s ready. Okay, so we start.

1

So I think sometimes, but with you, yeah, so I think the first question is just for learning purposes.

  • So it’s “what we get for breakfast today?”.

Okay, so you see the correct answer was here, but you wouldn’t get any points for that. So that was just the test though that you know what works. Okay, so from the next question onwards, you will get points. Okay. You will also get points for the correct answer. You get the number of points depends on how fast you are. And when you get several points in a row, then several right answers in a row, sometimes increases and there are some questions that you get more points than other questions. Okay. Okay. Okay.

2

So most of the right. I’m not going to be comfortable to work out. I just misleading you. So but the interning is not okay.

3

Okay. Okay. Yeah. The economy. The second economy was, again, to this degree. It’s actually the document economy. Some people will probably say, yeah, that’s a critical, but it’s actually tokenization of something. It’s not just all it has to do with the critical. So, you see, all those things that are…

4

This tricky. Oh, no. Okay, good. Oh, I look like I’ve been spotted. Yeah, okay, good. Now… Hey, what? Consumers? Now, because they produce something. Consumers, where the users have to get 1.0. Yeah, it was a currency. For those who have been there in the lecture, you know the red stones, and they use it as a currency. Although it wasn’t really movable, they used it as a currency. Yeah, that was the idea of piggy cash. Yeah, and the idea of piggy cash was that you send money and that you send some kind of a note to a bank, and the bank has a blind signature. So it signs the whole note in a blind way. So it doesn’t know who is providing this money. They are trying to buy this. They do it with having a blind signature. I think if you do that in an oral exam, in an oral exam, that would be something that I would probably say, and in an oral exam, I probably would have to find out. No, that was the correct answer. Okay, so yeah, it was, hash cash was this kind of email system, that wanted to reduce them. It’s time for email, that can be easily checked. It was the hash actually, and it was a group of what, and they didn’t do anything on cryptocurrency, although it was hash cash. Okay, who’s clanker? Okay, good. 2008 it was, 2009 the blockchain became live, January 2009, 2008. Okay, so this is a puzzle. Now you have to put things into the right order, and you get double points. Okay, so that’s the answer. Okay, so it’s a difficulty. Okay, so compute the hash, hash is this lower than the difficulty, it falls then plus one and start over, and it’s treated as a city-bound labor. So, we got four correct ones. Oh, this means that we got some tabulation now. Okay, so something’s coming up. Okay, so it’s not connected by the just the dot number, it’s connected by the hash. Because if you do the dot number, and you just choose the wrong one, the hash is guaranteed with the consistency of the whole thing. Sorry, that is enjoying, I think I thought we were just thinking about it. Okay, so you want to come out, good. Okay, so you want to answer the question. Okay, so the result is not fixed length. So, it doesn’t matter how long our input is, we always get result of fixed length. Input data cannot be computed based on the actual waveform, and minimal changes in input data result in minimal changes, that’s also not true, it’s because we have enough to take. So, if you do minimal changes on the input data, it has large effects on the output. So, you can just 1, 2, 3, and 1, 2, 3, 4, you get completely different results. So, it’s just result of fixed length, and it’s not in all the test cases. Yeah, it’s meant to be collision-free. And minimal charge. Yeah, collision-free. Okay, yeah. Okay, maybe for this point, yeah, now it’s gone. Okay, if you would argue in a written exam or in an old exam, that would be a good point. But you need to understand the collision-freeness, it should be almost collision-free. Computational. Yeah, invisible reading to get this. Okay. Okay, but it’s made a difference. Okay, so, again, several answers. That would be a good point. What would you do with a margin-free? Okay, so it has nothing to do with our form of transfer, and it’s not only used in blockchain, but it’s used in relation with wireless data, with the test data in truth result, and it’s pairwise hashing of the end nodes. Okay, that’s great. Good. You all got it. Good. So here goes just the five. Good. Okay. So it’s not delaying the network, but it’s not possible to do this. That’s the last network. We don’t modify the loop of what algorithm in itself, we would modify the parameters of this one, and we don’t modify the hash function, we just modify the difficulty, and that’s to ensure that if we have more or less computing power in the network, we always have about 10 minutes. Yeah? I have no idea. I have to check this. Okay, yeah, I know. I think that’s the whole idea of the course. So therefore it’s not an exam. What happens if you need a chart? I think that the moon chart is too big to see. No, no. Double chart. Remember in the slide, okay. So that is still possible. Yeah, I saw that at the end, a lot of things move. Yeah, go with us. So we are halfway. Double point. So it’s exoskeleton. You are not there. I said the colleagues tomorrow. That’s the good thing. In blockchain, the nodes do not trust each other. And it is in database, the nodes trust each other. So it’s a homogeneous system. They have the trust on the outside, and if you want to have it, they don’t trust each other. So the system can trust it, but the blocks, they don’t trust each other. That’s something you have to do quickly. Okay, someone was off the engine that the blockchain is suitable to scotch large amounts of data. So I told you wallet, because it’s on the sidewalk, not your keys, not your crypto. Remember that. Browser wallet, yeah, it’s in your browser, but the difference is being active. Your browser is being active. Paper wallet, you could argue about the paper wallet, but not many hardware wallets there. An additional pin, one lock. Paper wallet, paper wallet, Canberra wallet. Yeah, I would argue. I mean, this is something where you could argue. Which one? Depends whether you are more analog person or more digital person. Ah, Alex, that’s you. So, as you see, there are people coming up. Don’t give up. It’s the point. Wallets doesn’t spell the code. It spells your addresses, and it provides access to your code. So, tokens are actually being managed on an object. That’s the main thing. Remember that. Huffle? Battle points. Those were quick. So, the first, the wallet sends the authentication to the server, then the server sends fake challenge. The challenge in the scientist’s case, and then the server can validate that it really, the user, propels the user by checking the user’s public. In a simple way. I was going to travel on this topic. Someone is going to put it. So, it’s not centrally by authority. That’s the idea of the server. And it’s not score on a sentence. So, the point is that you can control your own data, and users are required to consent to the user’s identity. So, when you’re being asked, please show me that you are above 18. You don’t need to provide your birthday. You just need to provide food that you are above 18. That’s the idea of the server. So, it’s the architecture to internal data authenticity. And it’s to make a cryptographically verified claims about another party. You make a cryptographically verified claims that the person is above 18. And this algorithm provides a particular age. It’s not useful to throwing passwords. And it’s not the automatic method that has nothing to do with this convention. But, almost there. That’s perfect. Not centrally. So, you can up, right? Someone misguided. 33 is your computer scientist. Everything is based on truth. I never thought it would be. Okay? Three after a valid void is back in the name. Three after each other. I think we can increase points. And that was one. So, the transactions are moved to the network. And the miner is the mining incentive. Three people thought that the miner is slashed. No, you are not being slashed. If you are just misguided to validate the transactions and create a port, you are not kicked out. You are slashed when you misbehave completely and you try to cheat. And we discussed it explicitly that time. That’s wrong. Whether you stake 32 or 64, it’s no difference. If you have more than 32, let’s say you have 64, you just create a second miner. But you don’t put it just on the same miner. It has no effect. Three questions there. So, even the owner of the smart can’t modify that. But then he puts a backdoor inside. He can’t modify the code. He can modify the behavior intentionally. So, because all the questions you had to answer was wrong. So, the question that you can answer is yes. Okay. So, we do not require public verifiability. And then you can use it. We don’t need public verifiability. Okay, so let’s see. Okay, it’s all close to each other. At least here, we can have some movement. The last one I think is also double points. Okay, so let’s see. And it’s a long, you have to read it up. Okay. Okay. Okay. So, what is it? So, what is it at the moment? So, you checked it before. So, yes, it was in Europe. So, it’s almost the same price. Okay. Okay. So, who’s vegetable? That’s you. Okay. Good. Yeah. Congratulations. Well done. Thank you. So, you see your. Okay. So, we got one person. Didn’t do much about it. Okay. Exactly. Yeah. We have to think about it. Okay. They see very hard. But, okay. So, we got points. So, it is things. He gets it all, but he has to share it. He has to share it with the rest. So, does it.

Exam Questions

Okay. So, I think it gives you an idea of how much you really understood about the lecture and where you probably had some kind of what. Some kind of knowledge gets. Yeah. The final exam will have similar questions sometimes. Yeah. I mean, I will not ask you about the Bitcoin price. This is just to make some difference. Just to give some, some random factor to it. But the. So, I think when you, when you look at the slides and when you work through the exam, you see some kind of questions like the question about the properties of the hash function, what can you do with a Merkle tree, etc. I will not ask why blockchain is called blockchain. These are questions that we probably ask sometimes in an oral exam, just to get the ball rolling, to warm up. I think there will be so many people participating in the final exam that it will be written. And then there’s questions like… also good questions are the ones here with the… the last one is about public private, things like that, where should… what kind of use case should be applied for what, what are verifiable credentials, also the wallet question, what we actually store in the wallet. These are typical questions that you also find in the final exam. We can do a similar one at the, at the end of the lecture, so that you see whether you really know it or not.

org

Okay. Any questions? Yes, yes. Yeah. Yeah. Yeah. So we have the seven seven. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Six, seven seven. I’m sorry, the year in January. eleventh will be the last. No, no. The first will be the last one. So it’s five. Yeah, five lectures and things that we cover are smart contract programming. I think there’s something we talked about right away. January. You want to do something. It still has to learn something. I would tell you, please. So we started on smart contract programming. Then we talked about, once we did this, we can talk about NFTs, how to create NFTs, tokenize things, etc. Then we have a lecture on the IPFS, the Interplanetary File System, three. Then we have a lecture on the DeFi, Decentralized Finance, 4. And 5, this will be the last one, so we check whether we have something on the test again, or question and answer, all that.

Okay, good. So regarding the exercise for the next time, I suggest I will put up something about the lighting network. So that you understand what this is about. Because I think it’s also quite relevant and interesting.

And then I wish you a nice holiday time, Christmas or whatever you celebrate, and then we see each other next year. Bye-bye.

After Lecture

I think… Did someone else try to register for the exam? Yeah, yeah, I couldn’t because there was no contact. Yeah, okay, I checked it. Yeah. Yeah, that’s good. This is not managed by the central room management system. Yeah, but I didn’t think that was there. I’m trying, I’m saying. Maybe other new things on the process and generated the exam. I checked, yeah. Okay, what was it like? I think for me, the homework is something that you exercise and other people do. Oh, thank you very much. Happy holidays. Thank you. I think we have made some of them already. I just wanted to ask, this is from last time. Is there a new book there? I think it’s there. But I will revise it because I thought that I removed all the hash stuff. I will upload it. Okay, thank you. Have a nice Christmas. You too. Yeah. Okay. Okay. Okay.