A brief introduction about blockchain and it's components. For maybe 15 minutes. Then we move on to building our own blockchain from scratch with just Rust and some cryptography libraries.
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The blockchain created during the session.
Transcript
1 00:00:02.070 --> 00:00:28.269 Gabor Szabo: So Hi, and welcome to the Code Mavens, Youtube Channel and the Meetup group. If you are here, I'm really happy that somewhere have agreed to give this half presentation or quarter presentation, and mostly a pair programming style introduction to blockchain. I'm really happy that people are here who can listen and ask questions. Remember that this is going to be on Youtube. So if you don't want to be your.
2 00:00:28.270 --> 00:00:37.189 Gabor Szabo: I don't know name or or voice appear on Youtube. Then ask it in the in the chat, and I will notice it and and ask and
3 00:00:37.510 --> 00:00:39.770 Gabor Szabo: talk about it. Try to answer it.
4 00:00:40.570 --> 00:01:09.189 Gabor Szabo: and if you are watching the Youtube video. And if you enjoy this presentation and this meeting, then please also, like the video and follow the channel. So you will be updated. Later. Below the video, you will find a link to the repository that we are working on. I'll try to put everything into a Github Repository and push out to Github. So people who are in the Channel can follow so can pull and follow that code.
5 00:01:09.990 --> 00:01:13.550 Gabor Szabo: That's it. So so Rav. Thank you for agreeing
6 00:01:14.040 --> 00:01:20.739 Gabor Szabo: to to give this presentation, and it's your turn. Now please introduce yourself, and let's go from there.
7 00:01:21.190 --> 00:01:29.149 Sourav Mishra: Yeah, thank you so much. Gabor. So I'm Saurav. And I'm a core protocol engineer for shorter network. I have been that for the past 3 and a half years, maybe.
8 00:01:29.260 --> 00:01:35.259 Sourav Mishra: And my job is basically developing blocks and protocols from scratch using rust and a framework called substrate.
9 00:01:35.710 --> 00:01:37.300 Sourav Mishra: So today will be
10 00:01:37.600 --> 00:01:51.530 Sourav Mishra: learning a bit about blockchain, so I'll be presenting some something I have prepared slides for that, so we'll be learning about blockchains briefly, and then we'll be moving on to creating our own blockchain from scratch using rust, but not any framework. So it just plain vanilla rust and some cryptography grades.
11 00:01:51.900 --> 00:01:53.479 Sourav Mishra: So let's get started.
12 00:01:54.570 --> 00:01:56.020 Sourav Mishra: I'll share my screen now.
13 00:01:58.420 --> 00:02:03.009 Gabor Szabo: Yeah, you may. I mean, you call Co host. So you can. You can share your screen. Yeah.
14 00:02:03.970 --> 00:02:05.060 Sourav Mishra: Can you share my screen?
15 00:02:05.520 --> 00:02:19.980 Gabor Szabo: Yeah. Yeah. And just to know if anyone looks at me and sees that I'm looking upwards. That's because the the larger screen is above my my camera. So when? Where? I need to understand something and actually read the letters, and it's it's there.
16 00:02:20.120 --> 00:02:22.619 Gabor Szabo: So don't worry. I'd like to look at that.
17 00:02:24.690 --> 00:02:27.919 Sourav Mishra: Alright. So I will minimize zoom, and let's begin.
18 00:02:28.390 --> 00:02:29.539 Gabor Szabo: It's good, good.
19 00:02:29.750 --> 00:02:38.149 Sourav Mishra: So this is a presentation I used when I presented for the 1st time my 1st talk in my college. It is still relevant to us. So I'm still using this. So
20 00:02:39.050 --> 00:02:45.709 Sourav Mishra: before starting to build our own blockchain, we should understand what a blockchain is, and to understand that
21 00:02:45.970 --> 00:02:55.100 Sourav Mishra: the simplest of definitions would be. It's a chain of blocks. It's also the most ridiculous definition. But it's the one we're going to be working with, because it's also the easiest to understand.
22 00:02:55.540 --> 00:03:10.710 Sourav Mishra: So as anyone like, if you are a user or a developer, anyone who is remotely concerned about blockchains, you should be primarily focused on those 2 things. That is what exactly are these chains made up of? And what exactly, is the data that is contained within these blocks?
23 00:03:12.160 --> 00:03:21.580 Sourav Mishra: So when I say what data is contained, basically, we care about what type of data is contained, in what format it is contained and to what extent it is contained.
24 00:03:22.770 --> 00:03:29.520 Sourav Mishra: and it typically varies from different blockchain to blockchain, because they have different standards. But essentially
25 00:03:30.190 --> 00:03:33.670 Sourav Mishra: it contains of 2 things. One is the block header.
26 00:03:34.000 --> 00:03:35.959 Sourav Mishra: and other is the transaction data.
27 00:03:36.820 --> 00:03:41.950 Sourav Mishra: So Block Header contains 4 things not always, but usually
28 00:03:42.550 --> 00:03:53.139 Sourav Mishra: one of them is has of the previous block. So has, or a cryptographic has is just a 1 way function where you put some input and it gives you a fixed output, a random output, random string output.
29 00:03:53.670 --> 00:03:59.009 Sourav Mishra: And it is incredibly difficult or almost impossible to go back to the input from the output.
30 00:03:59.270 --> 00:04:05.929 Sourav Mishra: So once you have some input and you got the output already. So you cannot guess what the input was just by looking at the output.
31 00:04:06.040 --> 00:04:10.029 Sourav Mishra: or you cannot mathematically or programmatically go back to the input from the output.
32 00:04:10.820 --> 00:04:13.990 Sourav Mishra: So that's why hash functions are also called travel functions.
33 00:04:14.300 --> 00:04:20.139 Sourav Mishra: So yeah, so the current block has the hash of the previous block. That is how these blocks are chained.
34 00:04:20.459 --> 00:04:31.369 Sourav Mishra: and then it has a timestamp. So timestamp is the timestamp. When the block was added to the blockchain and nonce is something we're gonna look at it later, when we understand consensus, a particular consensus.
35 00:04:31.530 --> 00:04:34.440 Sourav Mishra: And then Merkel loot is something we're gonna look at right now.
36 00:04:35.210 --> 00:04:42.789 Sourav Mishra: So apart from the block header, we have transaction data. So all the transactions that should be included in this block. Go here
37 00:04:43.450 --> 00:04:46.149 Sourav Mishra: and let's go to the Merkel group. Now.
38 00:04:47.360 --> 00:04:52.459 Sourav Mishra: So marker load is basically a step by step, hash of the transactions.
39 00:04:52.560 --> 00:04:58.999 Sourav Mishra: So when you arrange the transactions in the way that I've arranged in the right hand side, it forms something called a mercury tree.
40 00:04:59.120 --> 00:05:02.219 Sourav Mishra: and the root of that maple tree is called a maple root.
41 00:05:02.620 --> 00:05:03.900 Sourav Mishra: So how do you?
42 00:05:05.643 --> 00:05:09.180 Sourav Mishra: You have the transactions? Let's say, transaction one to transaction 4.
43 00:05:09.660 --> 00:05:18.169 Sourav Mishra: Put them side by side, hash all the transactions. So after hashing transaction, one you get hash, one after hashing transition 2 you get hash, 2, so on and so forth.
44 00:05:18.620 --> 00:05:21.000 Sourav Mishra: Then we concatenate, hash one and hash 2,
45 00:05:21.230 --> 00:05:28.719 Sourav Mishra: and you hash it again. So you get hash, 1, 2 do the same thing with hash, 3 and 4. You get hash, 3, 4. Concatenate the hashes again.
46 00:05:28.830 --> 00:05:31.000 Sourav Mishra: then has it again. You get the mokal root.
47 00:05:31.490 --> 00:05:36.540 Gabor Szabo: Okay, I have a question. The the number of transactions is like always 4, or is just some.
48 00:05:36.540 --> 00:05:39.719 Sourav Mishra: No, no, it it can be anything like
49 00:05:40.020 --> 00:05:42.550 Sourav Mishra: it depends on what blockchain you're following. So
50 00:05:42.660 --> 00:05:51.120 Sourav Mishra: I just took 4 transactions because it was easier to demonstrate the merkel root. Using 4 transactions. It can be 5, 6, or 10, whatever it is. I mean.
51 00:05:51.360 --> 00:05:52.120 Gabor Szabo: Okay.
52 00:05:52.120 --> 00:05:57.749 Sourav Mishra: I think ideally, it should be 10 in some blockchains. It is 10. But yeah, you can decide that on your own. There is no.
53 00:05:57.750 --> 00:06:02.810 Sourav Mishra: and and the hashing algorithm that that is used is is a.
54 00:06:03.280 --> 00:06:07.580 Gabor Szabo: What kind of hashing which which hashing algorithm is is one of the well-known.
55 00:06:07.820 --> 00:06:17.480 Sourav Mishra: For our project. We are going to use Ss. 2, 56. Then it varies from blockchain to blockchain and algorithm. Some might use Blake. 3. Some might use something else.
56 00:06:17.680 --> 00:06:21.489 Sourav Mishra: But for our today's project we're gonna use haz 256.
57 00:06:21.890 --> 00:06:22.610 Gabor Szabo: Okay.
58 00:06:23.340 --> 00:06:27.729 Sourav Mishra: No, so any doubts so far regarding how the Murker route is constructed.
59 00:06:28.740 --> 00:06:30.710 Gabor Szabo: Yeah, more or less. Yeah, I understand.
60 00:06:31.440 --> 00:06:32.110 Sourav Mishra: I'm good.
61 00:06:32.500 --> 00:06:35.080 Sourav Mishra: So now let's move on to some blocking concepts.
62 00:06:38.100 --> 00:06:44.110 Sourav Mishra: So a blockchain is decentralized, that is, it is not owned by a single entity, or owned by a centralized entity.
63 00:06:44.220 --> 00:06:59.070 Sourav Mishra: Every participant in the network owns a local copy of that blockchain which to which they contribute, and then they flood that entire contribution to the whole network. And then the whole network adds it to their own local copies. So that's how everyone has the same copy. Essentially
64 00:06:59.410 --> 00:07:00.960 Sourav Mishra: at a given point of time.
65 00:07:00.960 --> 00:07:02.789 Gabor Szabo: Everyone has all the data.
66 00:07:03.040 --> 00:07:11.059 Sourav Mishra: Yeah, everyone needs to have all the data. Because, let's say, if I add a new block to the blockchain, I have to propagate it to the network, so that you guys can also add it to your team.
67 00:07:11.980 --> 00:07:12.910 Gabor Szabo: Okay.
68 00:07:14.480 --> 00:07:25.289 Sourav Mishra: And then it's immutable because of the hashes I just mentioned. So if you change if you change the tiniest bit in the block, then the entire block has changes drastically.
69 00:07:25.470 --> 00:07:37.780 Sourav Mishra: and since the blocks are linked by the hash of the previous blocks, so if the hash of one block changes, then all the hashes of the corresponding blocks that follow. They are all going to be changed, and you will be the only one
70 00:07:38.020 --> 00:07:42.360 Sourav Mishra: with a changed blockchain, so you will be immediately kicked out of yeah.
71 00:07:42.360 --> 00:07:55.600 Gabor Szabo: So one of the things that I'm really unclear to me is that I mean there are these nodes, I guess right that they are the block that on the node someone adds a new block to the chain.
72 00:07:56.149 --> 00:08:02.589 Gabor Szabo: And if what happens if 2 people on 2 different nodes add to the same
73 00:08:02.900 --> 00:08:10.990 Gabor Szabo: block, another one that so do they have now 2 blocks on the same route, same parent, parent, block.
74 00:08:12.630 --> 00:08:26.419 Sourav Mishra: Yeah, that is actually a highly technical concept. So what you just mentioned like, if you add 2 different blocks by 2 different people, and then it is propagated to the network at the same time. Then what you get is called a fork. So there are different algorithms to resolve forks.
75 00:08:26.860 --> 00:08:46.859 Sourav Mishra: and usually what happens is people follow the longest chain. So if the fork that you made has more blocks added to it after you, added the block, then that chain is usually considered valid, and the orphan chain that the other fork that is not considered valid is kind of discarded, and all the transactions are rolled back.
76 00:08:47.420 --> 00:08:58.540 Sourav Mishra: So the transaction that you added in your chain in your book, and you propagated that if it is not the longest chain, then it's kind of like. It's the transaction get rolled back and that entire chain is discarded.
77 00:08:59.210 --> 00:09:02.700 Sourav Mishra: and my chain gets to like replace the valid chain.
78 00:09:03.250 --> 00:09:10.970 Sourav Mishra: So that is one algorithm to solve. For there are other algorithms. I will not go deep into that because it's like really technical. Generally.
79 00:09:11.280 --> 00:09:17.670 Sourav Mishra: if a conflict, then the longest chain kind of gets validated and kept it as the new chain.
80 00:09:18.250 --> 00:09:19.070 Gabor Szabo: Okay.
81 00:09:20.420 --> 00:09:32.459 Sourav Mishra: All right. So I hope immutability is clear, because data once written, it cannot be changed because of the hashes. And if you change one tiny bit in one block. Then the entire blockchain becomes a different blockchain because of the hashes.
82 00:09:32.890 --> 00:09:40.250 Sourav Mishra: so you can be easily caught and kicked out of the network because of malpractice, because only you have the different chain, while everyone else has a different chain.
83 00:09:42.410 --> 00:09:43.110 Gabor Szabo: Right.
84 00:09:43.110 --> 00:09:52.209 Sourav Mishra: And then anonymity, because identities are unknown. So we don't use regular identities like email or passport, or names, or something
85 00:09:52.380 --> 00:10:01.019 Sourav Mishra: to like transact on the blockchain or mine blocks on the blockchain, or add blocks to the blockchain. We use something called a public key, about which I'm going to look at it later.
86 00:10:02.070 --> 00:10:16.550 Sourav Mishra: So yeah, next, it is transparent, because everything that is recorded is available openly to everyone. You can always query a blockchain and see all the transactions like nothing is hidden to anyone, so once it is written on the blockchain, it can be viewed by anyone
87 00:10:16.660 --> 00:10:17.490 Sourav Mishra: out there.
88 00:10:18.060 --> 00:10:19.330 Sourav Mishra: So it's transplanted
89 00:10:20.360 --> 00:10:26.510 Sourav Mishra: and coming back to anonymous again. So like I said, public key is used instead of regular identities like these.
90 00:10:26.780 --> 00:10:35.240 Sourav Mishra: So public keys are just it's a long bunch of heterdicimal numbers. So it's not easily
91 00:10:35.340 --> 00:10:47.799 Sourav Mishra: rememberable by humans. And it's not easily readable by humans also. So you can't look at 2 publications and tell that this belongs to this guy, and this belongs to this guy, unless you have a really good memory, and you can memorize all the public keys and to whom they belong to.
92 00:10:47.940 --> 00:10:52.309 Sourav Mishra: Otherwise it's kind of impossible to figure out who this belongs to.
93 00:10:52.490 --> 00:10:54.009 Sourav Mishra: That is why it's anonymous.
94 00:10:56.540 --> 00:10:59.899 Sourav Mishra: So yeah, now let's look a bit at public key cryptographic.
95 00:11:00.760 --> 00:11:08.539 Sourav Mishra: So it's also synonymous with a symmetric key. Cryptography. There is something called symmetric key cryptography, which is kind of less secure than this.
96 00:11:08.710 --> 00:11:13.959 Sourav Mishra: So in a symmetric key cryptography, you have 2 separate keys, one public key and one private key.
97 00:11:14.330 --> 00:11:15.819 Sourav Mishra: So you use the
98 00:11:16.691 --> 00:11:26.370 Sourav Mishra: private key. The private key is basically a secret key like, think of it as your email and password. So email, you say openly with everyone but your password. You keep it secret to yourself only
99 00:11:27.080 --> 00:11:37.179 Sourav Mishra: so. A private key is kept with you secretly, and a public key is propagated out of the world for, like, for sending money to you, or you send money to someone else, using a public key, etc. Etc.
100 00:11:38.500 --> 00:11:43.290 Sourav Mishra: And because it is asymmetric. So you encrypt with one key and decrypt with other.
101 00:11:43.480 --> 00:11:51.260 Sourav Mishra: So usually, what happens during signatures is you sign a message using a private key, and the other person can decrypt it, using your public key.
102 00:11:51.530 --> 00:11:54.950 Gabor Szabo: Is this the same like what what you use usually with sh! Right.
103 00:11:55.640 --> 00:11:56.690 Sourav Mishra: In what sorry.
104 00:11:56.690 --> 00:12:06.010 Gabor Szabo: In Ssh, when you're Ssh into somewhere, and then you're using private key and public key authentication unless you really want to type in your password every time.
105 00:12:06.170 --> 00:12:09.149 Sourav Mishra: Yeah, that's that's that's pretty much the same thing.
106 00:12:09.150 --> 00:12:09.840 Gabor Szabo: Okay.
107 00:12:09.840 --> 00:12:17.020 Sourav Mishra: 2 keys, you use one key to encrypt, and the other key to decrypt. Now it depends on you which key use, because if you encrypt with your
108 00:12:17.310 --> 00:12:34.809 Sourav Mishra: public key, then it has to be decrypted the private key, because it makes no sense, because nobody can decrypt that, because your private, supposedly secret to you, but if you do, encrypted with your private key, which is secret to you and you only other people can decrypt it with your public, and they can, you know.
109 00:12:35.290 --> 00:12:36.730 Sourav Mishra: very fair something like that.
110 00:12:40.410 --> 00:12:44.590 Sourav Mishra: and it's more secure than symmetric cryptography. Because, I said
111 00:12:45.000 --> 00:12:48.989 Sourav Mishra: in symmetric key cryptography, we use only one key for both encryption and decryption.
112 00:12:49.210 --> 00:12:54.029 Sourav Mishra: and it is really difficult to let the other party know what exactly your key is.
113 00:12:54.390 --> 00:13:02.860 Sourav Mishra: and it can easily be intercepted by attackers in the middle while you're setting keys. So if the key is lost, then your entire channel is like it's compromised.
114 00:13:04.750 --> 00:13:14.299 Sourav Mishra: and then Rsa and Ecc are the 2 most common algorithms for asymmetrically cryptography. Rsa was Rsa is not being used anymore, I guess, because Ecc is
115 00:13:14.650 --> 00:13:15.950 Sourav Mishra: much better than that.
116 00:13:16.070 --> 00:13:31.140 Sourav Mishra: So to just give an example. Acc keys provide the same amount of security with almost half the size of Rsa keys. So Ecc. Keys are like much more compact and easier to handle, plus the algorithm is modern. That's why Rsa is not being used
117 00:13:31.963 --> 00:13:34.789 Sourav Mishra: nowadays much. But Ecc is really popular.
118 00:13:36.790 --> 00:13:41.559 Sourav Mishra: So rac uses large prime numbers and their factorization to compute the keys.
119 00:13:41.720 --> 00:13:47.360 Sourav Mishra: So basically, you take 2 large prime numbers and you multiply them together.
120 00:13:47.560 --> 00:13:59.339 Sourav Mishra: And it is understood that, because if the product is also very large, because the plan numbers are very large, so it's not really easy to factorize the final product. So that is the base of Rc. Cryptographic.
121 00:14:00.110 --> 00:14:10.389 Sourav Mishra: and for Ecc you use elliptic curve. So you select a really large random number that's within the bound of the relative curve, and we multiply a generator point to that that gives you.
122 00:14:11.360 --> 00:14:12.750 Sourav Mishra: Is there a chat question.
123 00:14:13.650 --> 00:14:18.770 Gabor Szabo: No, no! I turn this off. I have this beep whenever someone connects.
124 00:14:19.480 --> 00:14:22.039 Sourav Mishra: Yeah, I thought, like somebody had a question or something.
125 00:14:22.280 --> 00:14:26.300 Gabor Szabo: No, no, I just I have this on. I I turn this off sorry.
126 00:14:29.490 --> 00:14:41.860 Sourav Mishra: So like, we're saying, Yeah, Ecc uses elliptic curves as their base. And you multiply a really large number with the generator point to get a public key, and that really large number is usually a private key.
127 00:14:42.730 --> 00:14:48.649 Sourav Mishra: So we don't go into details of how these curves work. But yeah, rac uses prime numbers and ecc uses electric curves.
128 00:14:49.590 --> 00:14:53.470 Sourav Mishra: We will be a particular electric curve today. It's called Sccp
129 00:14:53.760 --> 00:14:56.659 Sourav Mishra: to like in our project while they're building it.
130 00:14:57.430 --> 00:15:00.239 Sourav Mishra: It is the same curve that is used by the Bitcoin blockchain.
131 00:15:02.350 --> 00:15:03.140 Sourav Mishra: Alright.
132 00:15:03.699 --> 00:15:07.469 Sourav Mishra: Moving on. Let's look at the final part of the presentation. It's a
133 00:15:07.700 --> 00:15:13.340 Sourav Mishra: some consensus mechanisms. So basically consensus is how the
134 00:15:13.920 --> 00:15:18.050 Sourav Mishra: blockchain arrives at a unified decision, that yes, this is right, and this is wrong.
135 00:15:18.280 --> 00:15:21.179 Sourav Mishra: So the 1st consensus is proof of work
136 00:15:21.350 --> 00:15:28.819 Sourav Mishra: in which minus are the people who add blocks to the blockchain. So they solve complicated puzzles to validate transactions and create new blocks.
137 00:15:29.220 --> 00:15:33.090 Sourav Mishra: This requires a lot of computational power because of the nature of the puzzle.
138 00:15:33.510 --> 00:15:39.999 Sourav Mishra: So if you remember, we saw a keyword called nonce in our blog header when I was showing you the block diagram.
139 00:15:40.560 --> 00:15:45.419 Sourav Mishra: So basically minus, I trade over all possible.
140 00:15:46.130 --> 00:16:11.869 Sourav Mishra: And then they try to hash the block. And if the hash of the block matches a particular difficulty that is set by the blockchain, then that block is considered valid. So let's say, if I start with nonch equal to one. Then I hash all the block data. Then I check the hash. If it starts with, let's say, 3 zeros, then it should be considered valid, but mine starts with 2 zeros, then that nonce is not valid, so I try with nonce to. I do the same. I repeat the same process. Hash it, check it.
141 00:16:12.190 --> 00:16:16.929 Sourav Mishra: It doesn't. Then I increment the nonce nonce equal to 3. Then I do the same thing.
142 00:16:17.160 --> 00:16:28.310 Sourav Mishra: So it goes on and on and on, until I actually find a particular nonce that satisfies the difficulty of the blockchain. Difficulty in this case is how many leading Zeros the Hask should start with.
143 00:16:28.710 --> 00:16:40.980 Sourav Mishra: So if the number of leading zeros is 3, then the hash that the final hash that you get after finding the nonce, it should all start with 3 zeros. It doesn't matter what follows out of 3 zeros, but the hash should at least start with 3 zeros.
144 00:16:42.180 --> 00:16:52.539 Sourav Mishra: So the miners try with different values of nonce and under analyst they get to that. And the 1st person who solves this is the person who gets to mind the block and get the block reward.
145 00:16:53.720 --> 00:16:55.560 Sourav Mishra: So that is how proof of work works.
146 00:16:57.080 --> 00:16:57.910 Gabor Szabo: Okay.
147 00:16:59.940 --> 00:17:01.030 Sourav Mishra: Any doubts on this.
148 00:17:04.630 --> 00:17:15.509 Gabor Szabo: Yeah, it's it's it's a i read about it. And and I still don't really understand this whole whole mining thing. But I wonder if if that's really important for or
149 00:17:16.089 --> 00:17:18.040 Gabor Szabo: actual implementation.
150 00:17:18.349 --> 00:17:21.509 Sourav Mishra: It is. Actually, we're going to implement a proof of all blockchain today.
151 00:17:22.619 --> 00:17:23.839 Gabor Szabo: Okay. Good.
152 00:17:24.460 --> 00:17:26.690 Sourav Mishra: So. Which part did you want? Answer? I could explain it to you again.
153 00:17:27.859 --> 00:17:35.679 Gabor Szabo: I think we can just go on, and then if if I get to that point again, then then maybe that will clarify me.
154 00:17:36.169 --> 00:17:38.649 Gabor Szabo: And then we can get back to this. Okay.
155 00:17:39.010 --> 00:17:48.800 Sourav Mishra: But just to explain it once more for people who had trouble understanding it the 1st time, Rubov is basically a consensus in which miners need to solve for a particular value of nonce
156 00:17:48.910 --> 00:17:58.460 Sourav Mishra: that should satisfy the difficulty of the blockchain and difficulty of the blockchain, for example, could be something like the final hash of the block, could start with N number of zeros.
157 00:17:58.740 --> 00:18:12.309 Sourav Mishra: So let's say, if N equals to 2, and you choose a nonce value, and the final hash of the block starts with 2 zeros. Then that is considered a valid nonce and a valid block. And you get to mine. That block mining basically means adding the block to the blockchain.
158 00:18:12.700 --> 00:18:13.040 Gabor Szabo: Yeah.
159 00:18:13.380 --> 00:18:23.329 Sourav Mishra: If you're a miner, and you found the nonce first, st and your nonce satisfies the difficulty of the blockchain, then you get to mind the block 1st and get the block rewards.
160 00:18:23.850 --> 00:18:24.710 Gabor Szabo: Okay.
161 00:18:25.170 --> 00:18:29.469 Sourav Mishra: So basically, miners compete with each other to find the block or find the nonce first.st
162 00:18:30.810 --> 00:18:33.560 Sourav Mishra: Whoever finds it. 1st they get to mind the block and get the rewards.
163 00:18:35.630 --> 00:18:38.039 Gabor Szabo: Pricing. No, no, I get it. Yeah.
164 00:18:38.620 --> 00:18:42.379 Sourav Mishra: Yeah. And the next consensus is proof of stake.
165 00:18:42.600 --> 00:18:59.909 Sourav Mishra: It is a much lightweight consensus because it doesn't, doesn't need miners or validators to solve complex puzzles. Validators are basically chosen based on the amount they have stake and how long they have been a network participant and how long they have staked the amount. Usually it's about how much amount they have staked.
166 00:19:00.580 --> 00:19:09.639 Sourav Mishra: So people argue that this is a bit centralized because of the rich get richer mentality, because whoever has the most stake easily is chosen to be the validator for the next blog.
167 00:19:10.220 --> 00:19:13.200 Sourav Mishra: So that's there, and
168 00:19:13.380 --> 00:19:27.060 Sourav Mishra: you don't have to compete with anyone because you are chosen based on your stake. So if you're chosen as a validator, then you get to add the block to the blockchain. You don't have to like, compete with the other validators to find some particular value or something, and then add the block to the blockchain.
169 00:19:27.440 --> 00:19:30.610 Sourav Mishra: So that's how it is. Pretty energy efficient because
170 00:19:30.890 --> 00:19:33.069 Sourav Mishra: you just get chosen and you add the block.
171 00:19:33.660 --> 00:19:34.270 Gabor Szabo: That's up!
172 00:19:36.550 --> 00:19:41.189 Sourav Mishra: And the last example. The 3rd type of consensus is proof of authority.
173 00:19:41.590 --> 00:19:42.390 Sourav Mishra: So
174 00:19:42.760 --> 00:20:03.699 Sourav Mishra: this is by far the most centralized consensus, because only people with known authority are allowed to add blocks to the network. Like, say, if you're an organization, then the Board of Directors or the CEO, or the upper management, only they get to add the blocks because they have the authority to add the blocks. And the rest of the people are just network participants. They don't get to like, participate in the governance of the chain.
175 00:20:03.960 --> 00:20:10.450 Sourav Mishra: That's why it is more centralized. But then it really flourishes in those cultures like corporate cultures, or somewhere where you have a hierarchy.
176 00:20:13.240 --> 00:20:28.330 Sourav Mishra: so you can think of proof of authority to be similar to proof of stake. But instead of validators or minus or block address being chosen by the number of the amount of the stake they are just predefined by the authority they hold in the
177 00:20:28.560 --> 00:20:29.640 Sourav Mishra: automation.
178 00:20:30.580 --> 00:20:40.159 Gabor Szabo: There is a question here. The the idea is close to the question you asked before, what if 2 different nodes mine 2 blocks with the same parent.
179 00:20:40.460 --> 00:20:47.059 Gabor Szabo: We say the node with the longer chain wins. But why wouldn't Hacker just create extremely long chain?
180 00:20:47.690 --> 00:21:01.100 Gabor Szabo: The proof of work proves that you used work money into the creating your chain. It costs you money, so as long as a majority of players act honestly, hackers will have troubles to forge
181 00:21:01.310 --> 00:21:06.250 Gabor Szabo: blocks that are different than what the honest players are creating.
182 00:21:06.880 --> 00:21:11.729 Gabor Szabo: Okay? It was what? That was the question to clarification. Okay, thank you. Okay.
183 00:21:15.990 --> 00:21:18.300 Sourav Mishra: Yeah, so we can move forward.
184 00:21:19.530 --> 00:21:21.229 Gabor Szabo: Yeah, yeah, it's looking good.
185 00:21:21.230 --> 00:21:23.490 Sourav Mishra: Alright. So this kind of ends my presentation here.
186 00:21:24.100 --> 00:21:29.110 Sourav Mishra: So this is all I had to talk about. So this is all you should know before writing on blockchain.
187 00:21:29.880 --> 00:21:30.680 Gabor Szabo: Okay.
188 00:21:31.190 --> 00:21:34.709 Sourav Mishra: So if there are no questions, then we can directly start to the code.
189 00:21:35.510 --> 00:21:39.659 Gabor Szabo: Okay. So so now, should I share my screen now? Right.
190 00:21:39.790 --> 00:21:44.289 Sourav Mishra: Yes, can you please clone the repository that I just said the 1st one.
191 00:21:46.120 --> 00:21:48.450 Gabor Szabo: Should I clone that repository? Okay, yeah.
192 00:21:48.960 --> 00:21:52.179 Gabor Szabo: okay, let's just share the screen.
193 00:21:55.390 --> 00:21:58.900 Gabor Szabo: Okay? So you were supposed to see the
194 00:21:59.925 --> 00:22:03.680 Gabor Szabo: this one, the this one we want. I wanted right?
195 00:22:04.000 --> 00:22:04.570 Sourav Mishra: Yeah.
196 00:22:05.340 --> 00:22:07.250 Gabor Szabo: Okay.
197 00:22:18.070 --> 00:22:19.110 Gabor Szabo: okay.
198 00:22:21.990 --> 00:22:26.800 Sourav Mishra: And you can check out to the workshop branch. I think it's called board Maven Workshop.
199 00:22:28.530 --> 00:22:29.330 Gabor Szabo: Sorry.
200 00:22:30.730 --> 00:22:31.610 Gabor Szabo: Should I check?
201 00:22:32.200 --> 00:22:32.940 Sourav Mishra: Yeah.
202 00:22:33.945 --> 00:22:34.770 Gabor Szabo: There's a bridge!
203 00:22:35.080 --> 00:22:38.559 Sourav Mishra: Yeah. No code hyphen, mavin, hyphen workshop.
204 00:22:43.780 --> 00:22:46.240 Gabor Szabo: Even workshop.
205 00:22:47.286 --> 00:22:49.069 Sourav Mishra: Code hyphen maven hyphen workshop.
206 00:22:52.720 --> 00:22:54.770 Gabor Szabo: Wait a second. I'll I'll look at here here.
207 00:22:56.350 --> 00:23:07.370 Gabor Szabo: Code, maybe a workshop. Okay. Code me? And virtual, okay, hopefully, we are there.
208 00:23:10.810 --> 00:23:12.119 Sourav Mishra: Right. This is the one.
209 00:23:12.830 --> 00:23:19.129 Gabor Szabo: Just a second. It it opens the always opens into my other screen. Drag it here.
210 00:23:19.900 --> 00:23:24.169 Gabor Szabo: Okay, so we have the editor open.
211 00:23:30.130 --> 00:23:36.050 Sourav Mishra: But the reason why I asked you to clone is because it has some starter code that is otherwise. It cumbersome to write yourself.
212 00:23:37.120 --> 00:23:41.819 Gabor Szabo: Okay. So this is the, this is only the skeleton that we have. It is not the
213 00:23:42.140 --> 00:23:43.189 Gabor Szabo: the implementation. Yeah.
214 00:23:43.190 --> 00:23:44.559 Sourav Mishra: It's not the final product. Yeah.
215 00:23:45.260 --> 00:23:47.409 Sourav Mishra: we are going to build on top of this.
216 00:23:51.900 --> 00:23:52.610 Gabor Szabo: 3.
217 00:23:55.030 --> 00:23:56.479 Sourav Mishra: Yeah, let's let's begin then.
218 00:23:57.280 --> 00:24:05.870 Sourav Mishra: So I'll give you a quick walkthrough of what are the files we have here? So we'll be writing code to the main file. Only we're not going to create different files for the simplicity of the project.
219 00:24:06.690 --> 00:24:12.320 Sourav Mishra: and you might want to turn off your analyzer because it's going to show a lot of red lines because the code is not complete.
220 00:24:14.810 --> 00:24:28.350 Sourav Mishra: And so the files we have defined here is the main Rs file, which is our main file, and that is the main server file. Then there's a build dot Rs file that basically compiles our protocol. And if you go back to the proto folder.
221 00:24:30.070 --> 00:24:31.489 Gabor Szabo: If I go back to where? Sorry?
222 00:24:31.490 --> 00:24:33.300 Sourav Mishra: The proto folder, the 1st folder.
223 00:24:37.340 --> 00:24:39.010 Gabor Szabo: The Protocol.
224 00:24:39.440 --> 00:24:41.239 Sourav Mishra: Yeah. The 1st folder right above searching.
225 00:24:41.660 --> 00:24:44.330 Sourav Mishra: Yeah. And you open the blockchain at 2 to 5.
226 00:24:47.110 --> 00:24:48.250 Gabor Szabo: Sorry I didn't understand.
227 00:24:49.010 --> 00:24:59.640 Sourav Mishra: Yeah, so this is our protocol definition. So we have defined a service. And then there are some messages. I will come back to this file later, when we explain the main function.
228 00:25:00.210 --> 00:25:22.990 Sourav Mishra: But basically, we have integrated Grpc connections to our blockchain so that our wallet can connect to our blockchain, and send requests and requests like standard transaction, or get balance or get coins from the faucet. So these 3 things that you see on line 7, 10 and 13 from the Rpc lines. So basically, those are the methods that are exposed to our client.
229 00:25:23.590 --> 00:25:32.269 Sourav Mishra: So our client can submit a transaction to our blockchain. It can get balance from our blockchain, and it can get the faucet money from our blockchain. Basically.
230 00:25:33.390 --> 00:25:34.330 Gabor Szabo: Okay.
231 00:25:34.610 --> 00:25:38.529 Sourav Mishra: Yeah, and I'm using Grpc, hence the protofile, the Protobuff file.
232 00:25:40.460 --> 00:25:41.380 Gabor Szabo: Okay.
233 00:25:41.610 --> 00:25:43.029 Sourav Mishra: Let's go back to the main again.
234 00:25:45.750 --> 00:25:58.310 Gabor Szabo: Wait a second. There was some comment there, Pavel, I think that in bitcoins blockchain is the longest chain with the maximum aggregated pow difficulty, not simply the longest chain by the number of blocks.
235 00:25:58.600 --> 00:26:01.540 Gabor Szabo: Okay, that's just another comment. Thank you.
236 00:26:03.740 --> 00:26:07.170 Sourav Mishra: Okay, so let's move on to the main function. Main file. Yeah.
237 00:26:08.090 --> 00:26:08.680 Gabor Szabo: Yeah.
238 00:26:09.350 --> 00:26:11.460 Sourav Mishra: So we have a bunch of imports here.
239 00:26:11.780 --> 00:26:25.019 Sourav Mishra: Chrono is for managing date and time. Sccp is the curve that are using for sequences and key management, public and private key survey is for serializing and deserializing our transaction data mainly so that we can sign it.
240 00:26:25.200 --> 00:26:27.560 Sourav Mishra: And sh. A tool is basically, the
241 00:26:27.730 --> 00:26:34.920 Sourav Mishra: has an algorithm, the 2 56. And then Vet, Dq is something you're using for a transaction pool maintenance
242 00:26:35.160 --> 00:26:39.880 Sourav Mishra: and arc and mutex. We are using that for starting our blockchain server
243 00:26:40.400 --> 00:26:43.240 Sourav Mishra: and system. Time is because of timestamps again.
244 00:26:43.580 --> 00:26:47.580 Sourav Mishra: and tonic is something we are using to handle grpc.
245 00:26:47.720 --> 00:26:51.510 Sourav Mishra: otherwise it would be almost impossible for us to develop this without tonic.
246 00:26:51.980 --> 00:26:55.380 Sourav Mishra: and we have to write a lot of code by ourselves which is not advisable.
247 00:26:55.840 --> 00:27:00.419 Sourav Mishra: And then log is used for this logging info and one going to the console.
248 00:27:01.400 --> 00:27:07.349 Sourav Mishra: So this pub MoD blockchain is something that comes from the photograph file.
249 00:27:07.770 --> 00:27:11.249 Sourav Mishra: So tonic include proto gives us a module called blockchain.
250 00:27:11.850 --> 00:27:19.689 Sourav Mishra: and the Const faucet modechain address is just a random address. I mean, it's not exactly an address. It's just a string. But since we
251 00:27:19.890 --> 00:27:32.789 Sourav Mishra: representing addresses as strings, so I just put it here like this as a constant, because if it is a faucet transaction, then you don't need to actually verify the sender and receiver and everything else. You just quickly pass it on to the block
252 00:27:33.150 --> 00:27:34.530 Sourav Mishra: and add it to the blockchain.
253 00:27:34.980 --> 00:27:38.729 Sourav Mishra: So that's why I just created a separate, unique address for the faucet.
254 00:27:39.050 --> 00:27:43.250 Sourav Mishra: You can choose any address you wish, but I just do the social link to make it simple.
255 00:27:44.410 --> 00:27:49.180 Sourav Mishra: and then line number 18 onwards to line 26. We have
256 00:27:50.848 --> 00:27:57.390 Sourav Mishra: imports from the blockchain module that we just defined online 12. That is the Protobuf module.
257 00:27:57.640 --> 00:27:58.709 Sourav Mishra: so I'll commit.
258 00:27:58.710 --> 00:28:00.210 Gabor Szabo: 36.
259 00:28:01.360 --> 00:28:01.990 Sourav Mishra: Sorry.
260 00:28:02.370 --> 00:28:03.940 Gabor Szabo: You said line 36.
261 00:28:04.180 --> 00:28:05.979 Sourav Mishra: No, no line, 18 to 26.
262 00:28:06.250 --> 00:28:06.990 Gabor Szabo: Okay.
263 00:28:08.170 --> 00:28:11.230 Sourav Mishra: So these are all the blocks and model imports that we just defined above.
264 00:28:11.230 --> 00:28:12.480 Gabor Szabo: Okay. He's worse.
265 00:28:13.980 --> 00:28:14.660 Sourav Mishra: So
266 00:28:14.830 --> 00:28:24.459 Sourav Mishra: are not. Defined in rust code. This is just defined in the prototype file. But tonic helps us create these types for us so you can use them.
267 00:28:25.710 --> 00:28:26.550 Gabor Szabo: Okay.
268 00:28:28.140 --> 00:28:30.859 Sourav Mishra: Alright. Then can you go down to line 28.
269 00:28:36.060 --> 00:28:37.469 Gabor Szabo: 2838.
270 00:28:37.670 --> 00:28:41.580 Sourav Mishra: 2828, yeah, just a bit above. So you can see the other quote below. Also.
271 00:28:42.170 --> 00:28:43.050 Gabor Szabo: Okay.
272 00:28:43.070 --> 00:28:54.639 Sourav Mishra: Alright. So we have a consensus trade. So basically because we are creating a blockchain with a pluggable consensus mechanism. So we have a consensus trade. That kind of like.
273 00:28:55.170 --> 00:29:02.340 Sourav Mishra: You need to implement this straight for every consensus algorithm that you write so that we can use dynamic dispatch to
274 00:29:02.640 --> 00:29:16.649 Sourav Mishra: dynamically update the consensus whenever going like. If I want to select proof of work, I can choose proof of work. If I want to select proof of stake, I can select proof of stake. So the blockchain code doesn't change. Only my consensus implementation changes based on the trait.
275 00:29:18.400 --> 00:29:24.390 Sourav Mishra: And then we have the main function that I'll come back later after I defined everything else. So that's for the last.
276 00:29:25.160 --> 00:29:25.920 Gabor Szabo: Okay.
277 00:29:27.060 --> 00:29:30.080 Sourav Mishra: Now let's start writing codes.
278 00:29:30.610 --> 00:29:32.600 Sourav Mishra: One thing that we have been waiting for so long.
279 00:29:33.490 --> 00:29:36.870 Gabor Szabo: Yeah, every second. It's complaining about something.
280 00:29:37.520 --> 00:29:41.110 Sourav Mishra: Yeah, I mean, it will complain because a lot of things are missing.
281 00:29:41.820 --> 00:29:42.560 Gabor Szabo: Okay.
282 00:29:43.320 --> 00:29:48.729 Sourav Mishra: So I suggest for you to turn off your analyzer. Please disable it for the timing.
283 00:29:49.270 --> 00:29:50.959 Gabor Szabo: Yeah. Well, okay.
284 00:29:51.130 --> 00:29:53.180 Sourav Mishra: I mean, unless you're not bothered by the red lines. Then.
285 00:29:53.180 --> 00:29:55.630 Gabor Szabo: Yeah, it's it's okay. It's okay for me. No, no problem.
286 00:29:56.290 --> 00:29:56.850 Sourav Mishra: Alright.
287 00:29:58.340 --> 00:30:02.430 Sourav Mishra: So now let's define an enum called consensus type.
288 00:30:05.910 --> 00:30:06.700 Gabor Szabo: Skype.
289 00:30:07.430 --> 00:30:10.170 Sourav Mishra: On line 35. Let's define it.
290 00:30:11.210 --> 00:30:11.840 Gabor Szabo: Yeah.
291 00:30:12.150 --> 00:30:15.050 Sourav Mishra: You can slap a derived debug, and then define the enum.
292 00:30:16.610 --> 00:30:26.589 Gabor Szabo: I think the best if you type in. Okay. So I wanted you to do myself to type. But I don't. I'm not sure I understand the how do you spell this? What! What you want to? Continues.
293 00:30:27.115 --> 00:30:30.810 Sourav Mishra: Consensus. That's the one that you consensus type.
294 00:30:31.390 --> 00:30:35.830 Gabor Szabo: Oh, consensus type. Okay.
295 00:30:39.210 --> 00:30:40.519 Gabor Szabo: this is what you entered.
296 00:30:41.450 --> 00:30:42.880 Sourav Mishra: It's still loading for me.
297 00:30:43.571 --> 00:30:47.959 Gabor Szabo: It takes time. Oh, I didn't know that it takes time for you to to see what I'm typing.
298 00:30:50.515 --> 00:30:53.530 Sourav Mishra: Yes, this is what I wanted you to type.
299 00:30:54.780 --> 00:30:55.520 Gabor Szabo: Okay.
300 00:30:55.820 --> 00:31:01.609 Gabor Szabo: it's just copilot telling me. I mean, I guess it's reading your code. And then it's offering me the same thing.
301 00:31:01.610 --> 00:31:04.639 Sourav Mishra: That is also correct. Actually, I wanted you to type the same thing.
302 00:31:05.310 --> 00:31:06.350 Gabor Szabo: Okay.
303 00:31:06.350 --> 00:31:09.940 Sourav Mishra: Yeah, just add a derived debug on the above the email.
304 00:31:11.840 --> 00:31:12.600 Gabor Szabo: Sorry.
305 00:31:13.224 --> 00:31:17.239 Sourav Mishra: Derive debug a derive macro with debug rate implementation for the enum.
306 00:31:21.850 --> 00:31:23.400 Sourav Mishra: Let me write it in chat.
307 00:31:24.600 --> 00:31:28.900 Gabor Szabo: Derive. What drive? What should I drive if you clone or.
308 00:31:28.900 --> 00:31:30.079 Sourav Mishra: A debug debug.
309 00:31:30.340 --> 00:31:31.090 Gabor Szabo: Debug.
310 00:31:31.450 --> 00:31:32.120 Sourav Mishra: Yeah.
311 00:31:33.150 --> 00:31:34.000 Gabor Szabo: Okay.
312 00:31:42.190 --> 00:31:44.759 Gabor Szabo: Well, maybe. Oh, okay.
313 00:31:48.400 --> 00:31:49.830 Sourav Mishra: Yeah, d was not alone.
314 00:31:50.150 --> 00:31:51.701 Gabor Szabo: So, okay, so so
315 00:31:53.090 --> 00:31:58.390 Gabor Szabo: now that I I see that there is an issue that it takes time for you to load the
316 00:31:58.860 --> 00:32:12.719 Gabor Szabo: to see what I'm typing. Maybe it's really better that we switch back to the original, that you're going to type, and it's going to be faster. But it will have the same delay for all of us. What do you say?
317 00:32:14.330 --> 00:32:16.739 Sourav Mishra: I mean, I'm okay with typing, no worries. I can type in.
318 00:32:17.120 --> 00:32:20.919 Gabor Szabo: Okay. So maybe it's better. So let's switch back to you.
319 00:32:21.220 --> 00:32:26.287 Gabor Szabo: I'll leave it as it is now for myself. And then
320 00:32:28.477 --> 00:32:33.200 Gabor Szabo: stop the sharing, so you can share, and then and it might be easier.
321 00:32:35.840 --> 00:32:36.580 Sourav Mishra: Okay.
322 00:32:43.160 --> 00:32:46.679 Sourav Mishra: One sec. Let me just check out to the workshop branch.
323 00:33:22.950 --> 00:33:23.800 Gabor Szabo: Okay.
324 00:33:27.630 --> 00:33:28.830 Sourav Mishra: Everyone, see my screen.
325 00:33:30.933 --> 00:33:32.579 Gabor Szabo: Yeah, yeah.
326 00:33:33.050 --> 00:33:34.210 Sourav Mishra: I'll just turn off my video.
327 00:33:34.523 --> 00:33:37.340 Gabor Szabo: Maybe you can enlarge the font a little bit.
328 00:33:38.917 --> 00:33:40.170 Sourav Mishra: Zooming I mean.
329 00:33:40.730 --> 00:33:41.430 Gabor Szabo: Sorry.
330 00:33:41.760 --> 00:33:42.939 Sourav Mishra: Do you want me to zoom in.
331 00:33:43.710 --> 00:33:46.480 Gabor Szabo: Yeah. Zoom in. Yeah, please. Okay, that's fine. Fine.
332 00:33:46.480 --> 00:33:47.290 Sourav Mishra: Right? Okay.
333 00:33:47.930 --> 00:33:51.209 Gabor Szabo: Thank you. And then there was. There was a question in Oops.
334 00:33:51.960 --> 00:33:54.070 Gabor Szabo: I almost closed the window.
335 00:33:54.070 --> 00:33:55.930 Sourav Mishra: Is there a chat question?
336 00:33:56.950 --> 00:33:57.290 Gabor Szabo: So.
337 00:33:57.290 --> 00:34:02.659 Sourav Mishra: Sync. Okay, so send and sync are basically used to make something thread safe
338 00:34:02.940 --> 00:34:05.550 Sourav Mishra: because we are going to use multiple threads.
339 00:34:05.760 --> 00:34:10.420 Sourav Mishra: So we need our consensus rate to be thread safe so that it can be passed between threads
340 00:34:10.679 --> 00:34:15.429 Sourav Mishra: and sentencing don't need to be defined anywhere, because they are from the Russian Standard Library.
341 00:34:19.500 --> 00:34:21.649 Sourav Mishra: Alright. So let's begin.
342 00:34:34.860 --> 00:34:37.300 Sourav Mishra: Are you guys able to see it in real time? Or is it.
343 00:34:37.300 --> 00:34:40.770 Gabor Szabo: Yeah, you already derived. That's what I can see.
344 00:34:41.620 --> 00:34:47.920 Sourav Mishra: Okay, that's not the same tax manager.
345 00:34:47.929 --> 00:34:57.679 Gabor Szabo: I mean, if you say as you write, then we'll see when we'll be able to understand if you if you're if it happens at the same time, or if we can get some delay.
346 00:34:58.310 --> 00:35:02.199 Sourav Mishra: Alright. So I'll now define the enum per enum consensus type.
347 00:35:02.520 --> 00:35:09.340 Sourav Mishra: And just for clarity, we're going to define a different type as well. A different consensus type. So let's call it proof of state type.
348 00:35:09.790 --> 00:35:21.349 Sourav Mishra: But we are not going to implement this today. We just have to define it so that it will be clear for you why, we have different types here, and for proof of stake type, we are not going to take difficulty. Rather, we are going to take a means take.
349 00:35:21.560 --> 00:35:23.330 Sourav Mishra: and that would be a U 64.
350 00:35:26.050 --> 00:35:33.029 Sourav Mishra: So we have, anonym consensus type. And we have defined 2 consensus types of proof of work and proof of stake.
351 00:35:34.480 --> 00:35:38.689 Sourav Mishra: Now, next, we are going to define the other data types that are going to use.
352 00:35:38.800 --> 00:35:46.179 Sourav Mishra: So 1st comes a stripe for transaction. So this basically defines what our transaction is gonna look like.
353 00:35:47.110 --> 00:35:51.860 Sourav Mishra: We will essentially have a center address, a recipient address, and an amount
354 00:35:52.600 --> 00:35:57.590 Sourav Mishra: and timestamp and signature. So sender, receiver amount should be clear timestamp as well.
355 00:35:57.730 --> 00:36:01.929 Sourav Mishra: and signature is basically the signature of the sender who is sending the money to the receiver.
356 00:36:02.230 --> 00:36:04.088 Sourav Mishra: So we're gonna call it
357 00:36:05.080 --> 00:36:07.539 Sourav Mishra: pub, from which is a string.
358 00:36:08.480 --> 00:36:12.739 Sourav Mishra: And it's basically a string representation of a public key.
359 00:36:13.370 --> 00:36:17.660 Sourav Mishra: Then they're going to call like pub 2, which is the receiver.
360 00:36:17.960 --> 00:36:21.649 Sourav Mishra: Again, it's going to be an address in the string representation.
361 00:36:22.330 --> 00:36:27.270 Sourav Mishra: Then there is pub amount, which is the amount of money I'm sending it is gonna be 64.
362 00:36:28.350 --> 00:36:30.609 Sourav Mishra: Finally, timestamp is also 54.
363 00:36:30.850 --> 00:36:33.060 Sourav Mishra: Pool and signatory is the configured.
364 00:36:35.260 --> 00:36:44.260 Sourav Mishra: So this is our transaction type or transaction truck. So any transaction that we are going to register on the blockchain is going to be of this type containing these information.
365 00:36:44.510 --> 00:36:45.520 Sourav Mishra: this information.
366 00:36:45.790 --> 00:36:49.990 Sourav Mishra: So I'll slap a derive again, because I need it to be of specific types.
367 00:36:50.200 --> 00:36:52.309 Sourav Mishra: We look to implement specific traits.
368 00:36:52.570 --> 00:36:54.240 Sourav Mishra: So if we work.
369 00:36:55.250 --> 00:37:03.980 Gabor Szabo: So I still would like to get understand? A little bit more here. So there is a blockchain out there
370 00:37:04.700 --> 00:37:10.819 Gabor Szabo: functioning right? And now, what you're writing is some implementation of a node for it.
371 00:37:12.812 --> 00:37:15.619 Sourav Mishra: No, I am writing implementation of the blockchain itself.
372 00:37:16.100 --> 00:37:30.380 Gabor Szabo: The blockchain itself. So you assume that there's no blockchain. You just want to create a new blockchain, and in that blockchain this is going to be, and and for that blockchain we'll have to have a server and and clients right.
373 00:37:30.610 --> 00:37:36.549 Sourav Mishra: Yes, and that is internally handled by Grpc, using this definition.
374 00:37:38.090 --> 00:37:45.290 Gabor Szabo: The network connections are are implemented this way. Right? That's what you're saying.
375 00:37:45.630 --> 00:37:56.209 Sourav Mishra: Exactly. We'll learn more about that when we come to the main function, like how exactly a server is going to be implemented, how exactly. Our client has been implemented. So client is basically the wallet that I implemented. But we're not going to build that today.
376 00:37:56.510 --> 00:37:59.479 Sourav Mishra: So the second link that I sent to you. It's for the wallet.
377 00:38:00.090 --> 00:38:00.460 Gabor Szabo: It's.
378 00:38:00.610 --> 00:38:05.220 Sourav Mishra: Company built. You just use that to connect to the blockchain, and it also uses Grpc.
379 00:38:06.720 --> 00:38:07.410 Gabor Szabo: Yeah.
380 00:38:09.510 --> 00:38:16.969 Sourav Mishra: So the server part is kind of the last thing that I want to implement today. Before that I'm going to write the core logic of our blockchain and define the data types.
381 00:38:19.210 --> 00:38:24.869 Gabor Szabo: Okay. But so the the trans I mean the transaction has to be the same for all the clients. Right?
382 00:38:25.230 --> 00:38:31.724 Gabor Szabo: That's so. I wouldn't be able just to implement a client for an existing
383 00:38:32.730 --> 00:38:36.660 Gabor Szabo: blockchain without you reusing this information right?
384 00:38:37.630 --> 00:38:38.670 Sourav Mishra: Hmm!
385 00:38:40.080 --> 00:38:45.880 Sourav Mishra: I don't think I understood your question so like you want to define a client for an existing blockchain.
386 00:38:46.210 --> 00:38:46.930 Gabor Szabo: Yeah.
387 00:38:47.560 --> 00:38:57.499 Sourav Mishra: Yeah, you can do that. You don't have to create a blockchain for creating client like you can create a client for ethereum. You can create a client for Bitcoin. You can create client for Polka dot, or any other blockchain out there.
388 00:38:57.680 --> 00:39:01.580 Gabor Szabo: But you. You have to know what is the transaction format.
389 00:39:02.230 --> 00:39:18.880 Sourav Mishra: Yeah, you have to know what formats they follow like. What are the Rpcs. The blocks and has exposed to you that you can use in a client what what data types they use? What is the format? Etcetera, because all the code is open source. So you can just look at the code and check out.
390 00:39:18.880 --> 00:39:28.499 Gabor Szabo: I understand. Yeah, I didn't mean that you have to find out some secrets. It's just that you have to do the same thing as as they have done.
391 00:39:29.060 --> 00:39:29.810 Sourav Mishra: Yes.
392 00:39:30.140 --> 00:39:30.740 Gabor Szabo: Okay.
393 00:39:32.640 --> 00:39:33.430 Gabor Szabo: Okay.
394 00:39:33.830 --> 00:39:38.769 Sourav Mishra: All right, then I'm going to copy the same thing, the Debug Lone serialize and deserialize and put it there
395 00:39:38.930 --> 00:39:44.790 Sourav Mishra: and then I'm going to define a struct called block. So this is going to be our block structure.
396 00:39:45.200 --> 00:39:48.389 Sourav Mishra: and our blockchain is going to be made of these blocks.
397 00:39:50.420 --> 00:39:54.639 Sourav Mishra: So 1st thing that comes is the block number or the block index.
398 00:39:57.350 --> 00:39:59.320 Sourav Mishra: Then the timestamp
399 00:39:59.500 --> 00:40:04.939 Sourav Mishra: timestamp is basically the timestamp at which the block was added to the blockchain, like I mentioned earlier.
400 00:40:05.270 --> 00:40:11.450 Sourav Mishra: and it's going to be a date time of Utc.
401 00:40:14.160 --> 00:40:17.030 Sourav Mishra: Then we have transactions. So
402 00:40:17.890 --> 00:40:25.310 Sourav Mishra: we'll be using this thing that is defined here. It's going to be a web of good connection.
403 00:40:29.510 --> 00:40:36.069 Sourav Mishra: and then we'll have a previous hash. That is the previous hash of the that is, the hash of the previous block that this block comes after.
404 00:40:38.430 --> 00:40:41.159 Sourav Mishra: Then we'll have the hash of the current book
405 00:40:42.040 --> 00:40:46.549 Sourav Mishra: that is going to be used for for mining to check against this particular hash.
406 00:40:46.980 --> 00:40:48.710 Sourav Mishra: and of course the nonce.
407 00:40:50.270 --> 00:40:56.890 Sourav Mishra: This will be calculated again and again while you're mining, just to ensure that you match the difficulty, or you satisfy the difficulty of the blockchain.
408 00:40:57.340 --> 00:40:58.809 Sourav Mishra: and then pop! My number
409 00:40:59.150 --> 00:41:04.279 Sourav Mishra: miner, is the guy who mined this blockchain, so his address is there in the blockchain block.
410 00:41:06.830 --> 00:41:07.939 Sourav Mishra: Any doubts here.
411 00:41:11.360 --> 00:41:16.756 Gabor Szabo: No. But what? What kind of address is there? I mean, if you have an address of someone, then
412 00:41:17.810 --> 00:41:20.599 Gabor Szabo: there is some privacy issues. Right? So it's not.
413 00:41:20.600 --> 00:41:23.029 Sourav Mishra: No, the address is public for everyone to see.
414 00:41:25.052 --> 00:41:27.740 Sourav Mishra: Basically your public key.
415 00:41:28.160 --> 00:41:29.700 Gabor Szabo: The public key. Okay.
416 00:41:29.950 --> 00:41:35.640 Sourav Mishra: So instead of storing the public key directly, because I ran into serialization and deserialization issues.
417 00:41:35.800 --> 00:41:38.990 Sourav Mishra: So I am storing a string representation of the public key.
418 00:41:39.880 --> 00:41:40.770 Gabor Szabo: Okay.
419 00:41:40.770 --> 00:41:47.428 Sourav Mishra: So basically, a publicly is something really large, like, ff, a d, cp, something like this.
420 00:41:47.970 --> 00:41:51.870 Sourav Mishra: So I'm basically storing a string representation of this like this.
421 00:41:56.350 --> 00:41:59.840 Sourav Mishra: Okay, so this is our block struct and we're done in that.
422 00:42:00.770 --> 00:42:03.799 Sourav Mishra: The next thing to implement is our blockchain.
423 00:42:04.120 --> 00:42:07.010 Sourav Mishra: the stripe blockchain, not the real blockchain.
424 00:42:09.600 --> 00:42:14.730 Sourav Mishra: So the stripe blockchain will have a chain that is just a backup blocks.
425 00:42:21.340 --> 00:42:25.159 Sourav Mishra: Or our chain is basically a collection of blocks.
426 00:42:25.880 --> 00:42:28.480 Sourav Mishra: So hence the Vecer block, and then
427 00:42:28.890 --> 00:42:31.150 Sourav Mishra: we are going to have a transaction pool.
428 00:42:35.370 --> 00:42:38.279 Sourav Mishra: And this is where we're going to use the big Bq.
429 00:42:40.640 --> 00:42:42.860 Sourav Mishra: And of transaction.
430 00:42:45.750 --> 00:42:48.700 Sourav Mishra: And then we have del Ferra.
431 00:42:49.240 --> 00:42:51.029 Sourav Mishra: Pretty much consensus has already moved.
432 00:42:55.520 --> 00:43:00.529 Sourav Mishra: And, like I mentioned earlier, it's going to be box of dynamic dispatch because
433 00:43:01.160 --> 00:43:13.008 Sourav Mishra: we accept any consensus type that implements the trade consensus, so be it proof of work, or be it proof of stake as long as it implements the consensus trade for itself. We can accept that as
434 00:43:13.690 --> 00:43:16.229 Sourav Mishra: has the correct value for this type for this field.
435 00:43:20.940 --> 00:43:26.550 Sourav Mishra: Now we are done with this. So let's define our blockchain server.
436 00:43:34.940 --> 00:43:39.720 Sourav Mishra: It's going to take a blockchain, but it's not going to be something as simple as this.
437 00:43:41.310 --> 00:43:50.559 Sourav Mishra: because our blockchain server is actually a multi-threaded server. So on one thread it runs the server, and on another thread it mines the block
438 00:43:50.840 --> 00:43:51.690 Sourav Mishra: the blocks.
439 00:43:52.000 --> 00:43:57.879 Sourav Mishra: So that's why we're going to use arc and mutex arc, to ensure that
440 00:43:58.350 --> 00:44:06.579 Sourav Mishra: the references are shared safely between threads and mutex, to ensure that only one thread modifies the chain at one time.
441 00:44:06.700 --> 00:44:09.600 Sourav Mishra: because mutex provides us with a log a major electric block.
442 00:44:09.950 --> 00:44:16.039 Sourav Mishra: so that lock is especially helpful to ensure that only one thread modifies the blockchain at one time
443 00:44:16.470 --> 00:44:19.139 Sourav Mishra: to prevent the data is and deadlock and everything.
444 00:44:21.360 --> 00:44:25.030 Sourav Mishra: So yeah, this is our blockchain server, pretty simple just to contains the blockchain.
445 00:44:26.820 --> 00:44:30.123 Sourav Mishra: And then let's define the proof of what struck
446 00:44:34.580 --> 00:44:39.859 Sourav Mishra: this struct is the type for which we're going to implement the consensus trait.
447 00:44:40.500 --> 00:44:43.349 Sourav Mishra: It's going to have only one field. It's called difficulty
448 00:44:44.280 --> 00:44:49.629 Sourav Mishra: and difficulty. U, 32 basically means, if the difficulty is, let's say 2,
449 00:44:49.770 --> 00:44:54.019 Sourav Mishra: then that means the hash of the blocks would start with 2 zeros.
450 00:44:54.210 --> 00:45:00.000 Sourav Mishra: So the difficulty is 4. It means the hash of the block should start with 4 zeros for it to be accepted as a valid block.
451 00:45:00.750 --> 00:45:02.619 Sourav Mishra: So I'm taking it as U. 32.
452 00:45:03.720 --> 00:45:06.739 Sourav Mishra: So anything can go here that is under the
453 00:45:07.620 --> 00:45:13.260 Sourav Mishra: jurisdiction of the user who's starting the blockchain so it can be 2, 3, 4, anything that they want. So you 32 for that.
454 00:45:15.440 --> 00:45:19.470 Sourav Mishra: and then a simple implementation for proof of work. Just a constructor.
455 00:45:20.533 --> 00:45:25.180 Sourav Mishra: Mind you, this proof of work. Type is not the same as this proof of work variant.
456 00:45:25.640 --> 00:45:27.230 Sourav Mishra: Those are 2 different things.
457 00:45:30.160 --> 00:45:33.450 Sourav Mishra: So we write a function new for this.
458 00:45:36.710 --> 00:45:40.189 Sourav Mishra: and this parameter would be, I think this is correct.
459 00:45:40.910 --> 00:45:42.470 Sourav Mishra: Yeah, it's good.
460 00:45:43.030 --> 00:45:46.900 Sourav Mishra: So instead of proof of work, let's just say self to make it more generic. Yeah.
461 00:45:48.680 --> 00:46:02.669 Sourav Mishra: So we defined a proof of work struct for which we will be implementing the consensus type later, the consensus trait later, and we also implemented a constructor for the proof of work type that gives us a proof of work. Object by initializing the difficulty.
462 00:46:05.700 --> 00:46:10.499 Sourav Mishra: No, that's out of the way. Any doubts here, so far like the types you are defined so far.
463 00:46:16.980 --> 00:46:18.950 Sourav Mishra: So anything you want to go over again.
464 00:46:19.980 --> 00:46:22.520 Gabor Szabo: No, no! What was the question? Sorry?
465 00:46:23.240 --> 00:46:24.900 Sourav Mishra: I was asking if you guys have any doubts.
466 00:46:29.930 --> 00:46:31.600 Gabor Szabo: Looks good so far.
467 00:46:33.050 --> 00:46:37.219 Sourav Mishra: So now that we are done with all the types, let's start implementing stuff
468 00:46:37.740 --> 00:46:39.769 Sourav Mishra: like giving meaning to the types.
469 00:46:40.810 --> 00:46:43.810 Sourav Mishra: So the 1st thing we're gonna implement is
470 00:46:45.470 --> 00:46:52.970 Sourav Mishra: just a general implementation for the consensus type enum. This is the same enum as this, and
471 00:46:54.660 --> 00:46:57.849 Sourav Mishra: it will have a function called create consensus
472 00:47:01.520 --> 00:47:06.989 Sourav Mishra: that takes self, sorry ambers and so forth.
473 00:47:08.670 --> 00:47:12.730 Sourav Mishra: And it returns. The box consensus
474 00:47:13.270 --> 00:47:15.589 Sourav Mishra: which we need to use in our blockchain.
475 00:47:23.840 --> 00:47:26.150 Sourav Mishra: We're going to match because it's an enum.
476 00:47:27.820 --> 00:47:31.410 Sourav Mishra: So if it is let's say, self
477 00:47:33.420 --> 00:47:35.730 Sourav Mishra: proof of what type of difficulty?
478 00:47:38.000 --> 00:47:40.680 Sourav Mishra: Something wrong? Yeah, nobody.
479 00:47:41.900 --> 00:47:52.520 Sourav Mishra: Then we are going to return walks of new approve of what this is, how we just
480 00:47:52.750 --> 00:47:55.990 Sourav Mishra: work with boxes. So it's just plain the syntax
481 00:47:59.480 --> 00:48:04.350 Sourav Mishra: and difficulty something on.
482 00:48:08.510 --> 00:48:12.860 Sourav Mishra: Okay, we have not implemented consensus for proof of work. So yeah, it will go away soon.
483 00:48:13.450 --> 00:48:16.770 Sourav Mishra: Then let's do the same thing with self of proof of stake type.
484 00:48:18.960 --> 00:48:24.320 Sourav Mishra: We are not gonna implement that this time. But let's just have it, because otherwise our enemy is not complete.
485 00:48:26.850 --> 00:48:30.340 Sourav Mishra: I'll just put mean stake, that is this.
486 00:48:30.940 --> 00:48:33.280 Sourav Mishra: And here we can use the Tudo macro
487 00:48:33.520 --> 00:48:39.790 Sourav Mishra: because we're not gonna do it right now think it works good.
488 00:48:40.710 --> 00:48:55.478 Sourav Mishra: So what this create consensus does is it returns us a consensus box consensus based on the type we have selected. So if you want a proof of work consensus type, then we pass on the difficulty, and then we get a corresponding box type.
489 00:48:56.000 --> 00:49:00.070 Sourav Mishra: given given to us. And if you want to start with the proof of stake type, then
490 00:49:00.350 --> 00:49:03.890 Sourav Mishra: we'll do the same thing here, just copy and paste this.
491 00:49:04.490 --> 00:49:06.750 Sourav Mishra: instead of proof of work, make it proof of string.
492 00:49:07.210 --> 00:49:09.720 Sourav Mishra: and then, instead of new difficulty, make it main stick.
493 00:49:12.470 --> 00:49:18.400 Sourav Mishra: But we do not have a proof of stake type yet. So we are not going to implement this. Just keep it blank user.
494 00:49:18.400 --> 00:49:34.850 Gabor Szabo: One second, just one second. Sorry. So someone is asking about the the to do, Macro. So it's just panics with, with some explanation that it's you're about to implement that later on. So it's just a syntax placeholder.
495 00:49:37.630 --> 00:49:49.360 Sourav Mishra: So when you have to return something. But you don't have a particular return for that I generally use for when on in those cases you can do something like this. Also return your your empty type, but then it expects something like this.
496 00:49:49.530 --> 00:49:53.320 Sourav Mishra: so you can't easily, really use this. Hence the tutor Macro comes in handy.
497 00:49:56.180 --> 00:50:02.320 Sourav Mishra: and if you want, then you can add more types also here, like you can add a proof of authority type as well.
498 00:50:03.480 --> 00:50:11.470 Sourav Mishra: But again, that's up to you. If you want to implement those you can, you're free to do that. But for today's session we're not going to implement any of these just proof of work? Right?
499 00:50:13.310 --> 00:50:14.050 Sourav Mishra: Okay?
500 00:50:14.200 --> 00:50:21.839 Sourav Mishra: So it's now done, the consensor type implementation. Let's move on to implement block.
501 00:50:25.190 --> 00:50:30.949 Sourav Mishra: So block implementation will have 2 functions. One is obviously the constructor. That will give us a new block.
502 00:50:32.660 --> 00:50:36.429 Sourav Mishra: and it has the block index, which is v. 64.
503 00:50:38.810 --> 00:50:43.660 Sourav Mishra: And then you have the transactions, which is a lack of transaction.
504 00:50:46.780 --> 00:50:48.900 Sourav Mishra: and finally, the previous S.
505 00:50:51.940 --> 00:50:58.119 Sourav Mishra: It is a single did I misspell it, Stanga.
506 00:51:01.930 --> 00:51:04.790 Sourav Mishra: and it returns self. That is, it returns a block.
507 00:51:05.400 --> 00:51:11.319 Sourav Mishra: It takes in these parameters, and it returns a block to me.
508 00:51:12.340 --> 00:51:25.670 Sourav Mishra: So we're gonna construct a block. So let's new block smooth of type, block equals to self
509 00:51:29.870 --> 00:51:35.900 Sourav Mishra: index can be written as it is sort and syntax timestamp would be utc now
510 00:51:36.920 --> 00:51:41.379 Sourav Mishra: like the current timestamp, though time, when this thing is executed.
511 00:51:41.800 --> 00:51:44.540 Sourav Mishra: and then transactions again can be used as is
512 00:51:45.560 --> 00:51:49.669 Sourav Mishra: previous, has same thing with previous has that gave me everything will be nice.
513 00:51:50.200 --> 00:51:57.699 Sourav Mishra: So currently that hash of the block is empty, because we have not calculated that we need to calculate that amount
514 00:51:58.330 --> 00:52:06.219 Sourav Mishra: using the mining techniques, and the miner is also empty now, because you do not know who the miner is and the nonce is 0 again.
515 00:52:06.780 --> 00:52:10.249 Sourav Mishra: because that's something we're going to calculate repeatedly to make sure the hash
516 00:52:10.550 --> 00:52:13.269 Sourav Mishra: is in accordance with the difficulty of the blockchain.
517 00:52:17.200 --> 00:52:25.420 Sourav Mishra: Now I can go to block dot hash equals to blocked out. Calculate has.
518 00:52:26.130 --> 00:52:29.579 Sourav Mishra: So this calculate has method has not been defined yet.
519 00:52:31.470 --> 00:52:36.320 Sourav Mishra: and we're going to return block this.
520 00:52:40.390 --> 00:52:44.390 Sourav Mishra: Now. The very next function that we're going to define is calculate has, of course.
521 00:52:47.330 --> 00:52:51.930 Sourav Mishra: it takes a reference to self, that is, it takes a block, it's a method.
522 00:52:52.410 --> 00:52:56.270 Sourav Mishra: and it returns a string which is the hash of the block.
523 00:52:58.530 --> 00:53:03.360 Sourav Mishra: So to calculate hash, we need to initialize a hazard with the Sar. 256 new.
524 00:53:04.190 --> 00:53:06.370 Sourav Mishra: You can already see the syntax being suggested.
525 00:53:16.200 --> 00:53:21.679 Sourav Mishra: No, and then let's create a string to hash.
526 00:53:22.230 --> 00:53:28.189 Sourav Mishra: It cannot directly hash the struct as it is, so just need to create a string with the contents of the struct.
527 00:53:28.330 --> 00:53:33.579 Sourav Mishra: so we can call it input, or we can call it content. Whatever sales about. I just call it top
528 00:53:33.780 --> 00:53:35.030 Sourav Mishra: block content.
529 00:53:38.200 --> 00:53:44.050 Sourav Mishra: And it's gonna be, here's where you're gonna use certain
530 00:53:47.250 --> 00:53:49.040 Sourav Mishra: serialize it into a string.
531 00:53:59.000 --> 00:54:02.490 Sourav Mishra: What else is there self?
532 00:54:02.610 --> 00:54:04.350 Sourav Mishra: And on next.
533 00:54:05.720 --> 00:54:13.990 Sourav Mishra: So the timestamp. Basically everything that is contained in the block. We are going to hash that wait.
534 00:54:14.190 --> 00:54:17.289 Sourav Mishra: concatenate them, end to end and hash that
535 00:54:23.080 --> 00:54:34.560 Sourav Mishra: 12 floor transactions and self dot previouss and finally set up nods.
536 00:54:38.450 --> 00:54:40.199 Sourav Mishra: Then we're gonna unwrap this.
537 00:54:40.610 --> 00:54:44.750 Sourav Mishra: You should not actually force unwrap this because it's unsafe.
538 00:54:44.950 --> 00:54:52.969 Sourav Mishra: You should check if it produces a valid result and then unwrap it or handle the result accordingly, using an if letter match statement.
539 00:54:54.200 --> 00:54:56.050 Sourav Mishra: But for simplicity, I'll just use unwrapped.
540 00:54:57.190 --> 00:55:05.440 Sourav Mishra: And then you're gonna use hazard, dot update block content.
541 00:55:05.780 --> 00:55:12.490 Sourav Mishra: Don't ask bytes again. This is something that the hazard expects for us to do.
542 00:55:13.400 --> 00:55:16.350 Sourav Mishra: and then they're going to encode that into a hex string
543 00:55:28.660 --> 00:55:29.430 Sourav Mishra: keeps.
544 00:55:29.810 --> 00:55:32.929 Sourav Mishra: So now we also defined an implementation for our block.
545 00:55:33.110 --> 00:55:39.190 Sourav Mishra: So it has a new method, a new associated function that gives you a returns you a block.
546 00:55:39.420 --> 00:55:46.109 Sourav Mishra: and then a calculate hash method that takes the content of the block and creates a hash out of it.
547 00:55:46.790 --> 00:55:50.709 Sourav Mishra: So to use the has to calculate the hash, we're using Ssa 256.
548 00:55:51.290 --> 00:55:58.730 Sourav Mishra: That's the hashing algorithm. So we 1st initialize that with the hash, and then we create a string, using survey to string.
549 00:55:59.270 --> 00:56:00.490 Sourav Mishra: Then we
550 00:56:00.610 --> 00:56:06.440 Sourav Mishra: convert that string to bytes, and then we give those bytes to the hazard to actually has it.
551 00:56:06.560 --> 00:56:14.499 Sourav Mishra: And then, finally, after hashing it, we use hex import to import the final hash into a readable string or a storeable string.
552 00:56:15.080 --> 00:56:17.429 Sourav Mishra: because that's what we are expecting as a return.
553 00:56:19.060 --> 00:56:20.309 Sourav Mishra: Any doubts here.
554 00:56:24.200 --> 00:56:25.690 Gabor Szabo: Not from me.
555 00:56:26.720 --> 00:56:27.480 Gabor Szabo: Thanks.
556 00:56:27.700 --> 00:56:30.719 Sourav Mishra: I don't see any insights, either, so I guess you can proceed
557 00:56:33.300 --> 00:56:42.630 Sourav Mishra: again. This is all syntax like, I'm not defining these functions anywhere like, I have not defined update function anywhere, or I've not defined finalize function anywhere.
558 00:56:42.760 --> 00:56:45.830 Sourav Mishra: It comes to me when I use this.
559 00:56:46.050 --> 00:56:47.889 Sourav Mishra: These are all defined on this
560 00:56:50.600 --> 00:56:53.099 Sourav Mishra: alright. So our block implementation is done.
561 00:56:54.060 --> 00:56:55.850 Sourav Mishra: We are almost halfway there
562 00:56:58.020 --> 00:57:04.390 Sourav Mishra: and then, finally, a big chunk of our implementation implement consensus for proof of work.
563 00:57:05.990 --> 00:57:08.619 Sourav Mishra: This is one of the major parts of our program.
564 00:57:10.340 --> 00:57:17.029 Sourav Mishra: What basically, this implementation is gonna do is it is gonna make proof of work type compatible to be used
565 00:57:17.170 --> 00:57:18.870 Sourav Mishra: ought to be returned like this.
566 00:57:19.310 --> 00:57:23.009 Sourav Mishra: and in turn to be used in our blockchain.
567 00:57:24.450 --> 00:57:29.899 Sourav Mishra: So currently, I can't just use proof of work as a consensus because it has not implemented the consensus rate yet.
568 00:57:30.200 --> 00:57:34.610 Sourav Mishra: and it needs to implement that consistent state because I am using dynamic dispatch with box.
569 00:57:36.380 --> 00:57:38.390 Sourav Mishra: So although I'm returning it here.
570 00:57:38.580 --> 00:57:43.809 Sourav Mishra: You can see if I comment this, I get an error here
571 00:57:44.210 --> 00:57:47.399 Sourav Mishra: because consensus is not implemented by proof of our collect.
572 00:57:47.700 --> 00:57:51.709 Sourav Mishra: So if I implement this, or if I just tried right this.
573 00:57:51.930 --> 00:57:53.490 Sourav Mishra: then you can see these error groups.
574 00:57:53.840 --> 00:57:57.399 Sourav Mishra: because now we have an implementation for consensor, for
575 00:57:59.600 --> 00:58:07.290 Sourav Mishra: so we can see the methods that the consensus trade incorporates these 4 methods. Let's just copy and paste this for simplicity.
576 00:58:09.650 --> 00:58:11.209 Sourav Mishra: So we're gonna implement these.
577 00:58:11.560 --> 00:58:16.219 Sourav Mishra: So the 1st method that they're going to implement is the generate block method
578 00:58:22.000 --> 00:58:24.249 Sourav Mishra: amenities, because it's distracting. Yeah.
579 00:58:25.640 --> 00:58:30.340 Sourav Mishra: So how do we generate a block when it comes to proof of work.
580 00:58:32.070 --> 00:58:36.980 Sourav Mishra: I just explained how mining works and everything works. So how exactly do we generate a block in proof of works
581 00:58:38.130 --> 00:58:45.659 Sourav Mishra: so generating a block means we are finding a block that whose hash matches the difficulty parameters.
582 00:58:46.380 --> 00:58:55.170 Sourav Mishra: So we're gonna say, let mute block equals to block of new.
583 00:58:58.510 --> 00:59:05.089 Sourav Mishra: We can see what's provided to us. Already we have the index. We have the transactions, and we have the previous has
584 00:59:05.340 --> 00:59:14.430 Sourav Mishra: exactly the things that we need for this new function. We need the index, the transactions, and the previous S, and we are getting that
585 00:59:14.960 --> 00:59:16.099 Sourav Mishra: in this.
586 00:59:17.370 --> 00:59:20.190 Sourav Mishra: So I can just directly pass it like this index.
587 00:59:20.780 --> 00:59:22.539 Sourav Mishra: and the accents and previous has.
588 00:59:23.110 --> 00:59:24.549 Sourav Mishra: And now I have a block.
589 00:59:25.570 --> 00:59:32.459 Sourav Mishra: Now, what do I do with this block? I I got a block. Yes, but right now this block does not satisfy the difficulty, like I do not know if it does
590 00:59:33.040 --> 00:59:36.449 Sourav Mishra: so, I would say I would 1st set a target
591 00:59:39.730 --> 00:59:42.640 Sourav Mishra: equal to 0, and I'll repeat it.
592 00:59:43.390 --> 00:59:48.270 Sourav Mishra: How many times do I get to repeat it? I get to repeat it difficulty number of times.
593 00:59:48.470 --> 00:59:57.799 Sourav Mishra: like I showed back. Then, if my difficulty is 3, then this 0 is repeated 3 times, if my difficulty is 4, it's repeated 4 times, so on and so forth.
594 01:00:00.690 --> 01:00:01.940 Sourav Mishra: Something wrong.
595 01:00:11.850 --> 01:00:14.339 Gabor Szabo: And wanted you you to make it u size.
596 01:00:15.270 --> 01:00:21.240 Sourav Mishra: Yes, I'll do one better. I'll make this 2 size.
597 01:00:22.100 --> 01:00:22.950 Gabor Szabo: Oh, okay.
598 01:00:27.470 --> 01:00:35.780 Sourav Mishra: So that is done. Now, we have also defined our target. Now, we just need to check in a loop whether or not our block starts with this given target.
599 01:00:36.520 --> 01:00:38.110 Sourav Mishra: So we're going to take a while loop.
600 01:00:38.350 --> 01:00:45.310 Sourav Mishra: because that's the most feasible here. And we're gonna check. If the block pass starts with
601 01:00:48.920 --> 01:00:50.010 Sourav Mishra: our target.
602 01:00:53.610 --> 01:01:05.020 Sourav Mishra: Our target is basically a string of zeros, repeated difficulty number of times. So if our difficulty is 3, then our target is 3 3 zeros. If our difficulty is 4, then our target is 4 zeros, so on and so forth.
603 01:01:05.190 --> 01:01:11.170 Sourav Mishra: So I'm checking. If my, it's block, not black. Sorry. Yeah, if the block has starts with
604 01:01:11.550 --> 01:01:14.329 Sourav Mishra: differentiating number of zeros. That is our target.
605 01:01:14.600 --> 01:01:19.960 Sourav Mishra: then it's a valid block. Otherwise I enter the loop, and I increment the nonce by one.
606 01:01:20.120 --> 01:01:21.610 Sourav Mishra: and recalculate the hash again.
607 01:01:25.350 --> 01:01:32.869 Sourav Mishra: So by the time I exit this loop I expect that my block has is actually the asset I need. So I can just return the block.
608 01:01:35.840 --> 01:01:40.290 Sourav Mishra: So this ends our generate block method. In case of proof of work
609 01:01:40.470 --> 01:01:44.619 Sourav Mishra: for proof of stake, it will be substantially different. So let's not go there right now. But yeah.
610 01:01:44.950 --> 01:01:55.170 Sourav Mishra: the reason why we have a consensus rate is because these methods are going to differ between algorithms. So for proof of work which is different for proof of sticker, it's going to be different. So on and so forth.
611 01:01:56.480 --> 01:01:58.570 Sourav Mishra: Let's start with the validated block. Now.
612 01:02:03.130 --> 01:02:09.870 Sourav Mishra: So for validating a block and proof of work, or, let's say, any consensus, it's gonna be bit generic.
613 01:02:10.100 --> 01:02:17.050 Sourav Mishra: We're going to see that if the blocks previous has is actually equal to the previous has like it's during the previous has.
614 01:02:17.180 --> 01:02:22.579 Sourav Mishra: And we're going to check if the block hash is actually equal to the calculated hash of the block.
615 01:02:23.030 --> 01:02:27.510 Sourav Mishra: And then we're gonna finally check. If the block hash starts with the target.
616 01:02:28.750 --> 01:02:36.130 Sourav Mishra: So those 3 things here, we're just gonna go one by one over them. The 1st thing if Block Dot previous has equals to previous has
617 01:02:39.680 --> 01:02:42.280 Sourav Mishra: articles to big business.
618 01:02:43.780 --> 01:02:49.140 Sourav Mishra: then I'm going to say, that the block is not valid, so I return false.
619 01:02:54.218 --> 01:03:00.710 Sourav Mishra: Then I'm going to check if the block has is
620 01:03:01.350 --> 01:03:04.180 Sourav Mishra: what I calculate using. The calculate has method.
621 01:03:06.700 --> 01:03:10.190 Sourav Mishra: If it is not, then again return false.
622 01:03:13.750 --> 01:03:17.739 Sourav Mishra: And finally, I'm gonna check. If the block has starts with
623 01:03:25.170 --> 01:03:28.929 Sourav Mishra: 0 repeated difficulty number of times.
624 01:03:34.410 --> 01:03:40.489 Sourav Mishra: So these are the 3 checks that I am checking to ensure that the blog that I just received is a valid blog or not.
625 01:03:41.130 --> 01:03:45.019 Sourav Mishra: This check is necessary, because the one that I calculated here
626 01:03:45.880 --> 01:03:52.160 Sourav Mishra: has the has as an empty string, the nonce has 0, and the minor also as distinct
627 01:03:52.570 --> 01:03:54.170 Sourav Mishra: an empty address.
628 01:03:54.970 --> 01:04:00.739 Sourav Mishra: But this has changed. At least these 2 are changed when I and go to generate, blog.
629 01:04:01.370 --> 01:04:09.759 Sourav Mishra: So generate block updates my nons and my has until and unless it satisfies this difficulty, and when it satisfies the difficulty, it returns me the block.
630 01:04:10.110 --> 01:04:13.509 Sourav Mishra: So after I am calling this generate block function, my block has changed.
631 01:04:13.800 --> 01:04:16.689 Sourav Mishra: At least these 2 fields may not work have changed
632 01:04:18.350 --> 01:04:21.449 Sourav Mishra: so because they have changed. I need to check that.
633 01:04:21.740 --> 01:04:28.200 Sourav Mishra: The current block has equals to. When I calculate. The has 1st just a fallback method
634 01:04:28.380 --> 01:04:32.840 Sourav Mishra: just to ensure that it all works out alright.
635 01:04:33.910 --> 01:04:36.790 Sourav Mishra: And then we have the start method.
636 01:04:42.290 --> 01:04:51.899 Sourav Mishra: So the start method is where we're going to implement a separate thread that is gonna start our consensus algorithm and start mining and all.
637 01:04:52.080 --> 01:04:58.499 Sourav Mishra: So we're going to implement this a bit later, and because it returns nothing. So I can just do this. And it's gonna work.
638 01:04:58.930 --> 01:05:02.930 Sourav Mishra: And for now let's do this, will it work, or should it. Clown. Yeah, that's okay.
639 01:05:04.650 --> 01:05:06.400 Sourav Mishra: We are going to implement that later.
640 01:05:06.850 --> 01:05:10.409 Sourav Mishra: And the name function is the simplest function in this.
641 01:05:10.590 --> 01:05:11.780 Sourav Mishra: And I pause it.
642 01:05:12.050 --> 01:05:13.940 Sourav Mishra: Just return the name of the consensus.
643 01:05:14.960 --> 01:05:15.790 Sourav Mishra: That's all.
644 01:05:17.520 --> 01:05:18.220 Sourav Mishra: Yeah.
645 01:05:20.290 --> 01:05:21.769 Sourav Mishra: Any doubts so far.
646 01:05:22.000 --> 01:05:25.720 Sourav Mishra: Don't worry about the start. We're gonna do that later, very soon. In fact.
647 01:05:28.240 --> 01:05:30.939 Gabor Szabo: No, I think you're going. You can see you can go ahead.
648 01:05:31.550 --> 01:05:32.160 Sourav Mishra: Okay.
649 01:05:36.670 --> 01:05:37.440 Sourav Mishra: alright.
650 01:05:38.890 --> 01:05:45.349 Sourav Mishra: So we're done with the implementation for consensus for proof of work. Now let's implement blockchain.
651 01:05:51.560 --> 01:05:55.729 Sourav Mishra: So again, as usual, start with our constructor
652 01:06:02.050 --> 01:06:05.830 Sourav Mishra: to initialize a blockchain, we are gonna start it with a consensus.
653 01:06:19.270 --> 01:06:27.589 Sourav Mishra: 1st thing that we do is we need to define the Genesis block. Genesis block is the 1st block in the blockchain. It's called a Genesis block.
654 01:06:28.930 --> 01:06:30.760 Sourav Mishra: So when we start a blockchain.
655 01:06:31.920 --> 01:06:34.010 Sourav Mishra: we need to define the Genesis block.
656 01:06:34.530 --> 01:06:38.899 Sourav Mishra: and from there the blocks into the roots like new blocks get added to that.
657 01:06:42.320 --> 01:06:45.938 Sourav Mishra: Then it says, blocks based on this. It's
658 01:06:47.360 --> 01:06:52.710 Sourav Mishra: Then census dot generate block.
659 01:06:56.650 --> 01:07:01.460 Sourav Mishra: So we wrote this generate block function method to give us a block.
660 01:07:02.170 --> 01:07:04.660 Sourav Mishra: it returns a block. So we are going to use that.
661 01:07:05.970 --> 01:07:08.630 Sourav Mishra: And internally it uses block of name.
662 01:07:10.600 --> 01:07:13.269 Sourav Mishra: So you're gonna pass the arguments now.
663 01:07:13.530 --> 01:07:15.553 Sourav Mishra: So the index is
664 01:07:16.750 --> 01:07:20.159 Sourav Mishra: it's going to be 0 because it's in this block. So we start with 0,
665 01:07:20.470 --> 01:07:26.850 Sourav Mishra: and then we do not have any transactions yet in the dentist blog. So let's do this.
666 01:07:27.798 --> 01:07:33.859 Sourav Mishra: We can do wake off new, or we can just do a web macro with empty whatever sales about ending works.
667 01:07:35.100 --> 01:07:42.079 Sourav Mishra: And finally, the previous has is going to be 0,
668 01:07:45.630 --> 01:07:50.790 Sourav Mishra: because the genesis block is the 1st block, so there is no previous hash as such.
669 01:07:51.090 --> 01:07:52.890 Sourav Mishra: Hence let's keep it 0.
670 01:07:54.940 --> 01:07:58.710 Sourav Mishra: So that's done, then let's add a login
671 01:08:24.340 --> 01:08:25.929 Sourav Mishra: and return self.
672 01:08:26.620 --> 01:08:33.750 Sourav Mishra: So for chain, we have our initial block ready. So it's going to be Genesis block of deck.
673 01:08:34.880 --> 01:08:40.589 Sourav Mishra: And then for the transaction pool, it's going to be empty. We're clicking you because we don't have
674 01:08:40.819 --> 01:08:43.510 Sourav Mishra: a transaction pool rate just while you're starting.
675 01:08:44.430 --> 01:08:48.400 Sourav Mishra: And then the consensus, the one that we received here.
676 01:08:50.590 --> 01:08:53.600 Sourav Mishra: So that's the constructor for the the blockchain.
677 01:08:57.050 --> 01:09:01.859 Sourav Mishra: Now, we're going to define a function that is going to add a transaction to our blockchain
678 01:09:05.779 --> 01:09:06.740 Sourav Mishra: so.
679 01:09:09.940 --> 01:09:11.120 Sourav Mishra: or
680 01:09:13.220 --> 01:09:17.999 Sourav Mishra: describe the success. If the translation was added successfully, then it's true. If it was not, then it's false.
681 01:09:18.560 --> 01:09:26.190 Sourav Mishra: It's going to be taking a mutable self because the blockchain state is going to change. Once we add the transaction, so it's supposed to be mutable.
682 01:09:27.390 --> 01:09:29.300 Sourav Mishra: And then the transaction
683 01:09:32.430 --> 01:09:34.639 Sourav Mishra: is the transaction that you are trying to add
684 01:09:44.149 --> 01:09:47.920 Sourav Mishra: so like I mentioned earlier, if the transaction is from a faucet
685 01:09:48.822 --> 01:09:53.290 Sourav Mishra: like, if it is a faucet transaction, then we're just going to skip it and return through.
686 01:09:58.340 --> 01:09:59.840 Gabor Szabo: What is this for, sir?
687 01:10:00.980 --> 01:10:01.570 Sourav Mishra: Sorry.
688 01:10:01.890 --> 01:10:03.150 Gabor Szabo: What is this?
689 01:10:04.390 --> 01:10:06.369 Gabor Szabo: Was it? Mock chain address.
690 01:10:07.616 --> 01:10:09.970 Sourav Mishra: It's the const we have defined above.
691 01:10:12.270 --> 01:10:17.839 Sourav Mishra: So basically, a faucet is somewhere where you request funds from the blockchain for testing the blockchain out.
692 01:10:18.110 --> 01:10:25.920 Sourav Mishra: So if I am requesting funds to test the blockchain out, then I don't really need to go through verification and everything, because it's just a faucet request.
693 01:10:26.020 --> 01:10:28.149 Sourav Mishra: so it should automatically pass through.
694 01:10:29.540 --> 01:10:30.610 Gabor Szabo: Okay.
695 01:10:31.620 --> 01:10:35.990 Sourav Mishra: Yeah. So I'm skipping everything that follows. If the transaction is a partial transaction.
696 01:10:39.000 --> 01:10:40.990 Sourav Mishra: I will add a logger here.
697 01:10:41.460 --> 01:10:44.719 Sourav Mishra: This, let's say it's adding transaction to the faucet.
698 01:10:48.870 --> 01:10:51.269 Sourav Mishra: The transaction from faucet to pool
699 01:11:08.710 --> 01:11:16.100 Sourav Mishra: transaction.com and transaction dot month.
700 01:11:16.520 --> 01:11:19.159 Sourav Mishra: Let's make it a bit more robust.
701 01:11:20.420 --> 01:11:30.640 Sourav Mishra: Shit faucet address is this and online is this?
702 01:11:33.340 --> 01:11:36.510 Sourav Mishra: Yeah, that's done.
703 01:11:37.350 --> 01:11:47.179 Sourav Mishra: And I'm going to add this transaction to the transaction pool, because, even though it's a false transaction, it's still a valid transaction, and it is supposed to be inside the pool to mine.
704 01:11:48.610 --> 01:11:53.389 Sourav Mishra: I have the connection here. So, and finally, on returning to
705 01:11:57.540 --> 01:11:58.270 Sourav Mishra: okay.
706 01:11:58.900 --> 01:12:07.929 Sourav Mishra: so we successfully handled the faucet transaction. If it is a faucet transaction, then you will log that it's a faucet transaction. Then you push the transaction to the pool, and then you return through.
707 01:12:09.900 --> 01:12:12.249 Sourav Mishra: Next, we're going to verify the transaction.
708 01:12:15.350 --> 01:12:18.740 Sourav Mishra: If transaction got verified.
709 01:12:19.730 --> 01:12:22.939 Sourav Mishra: Wait. Have you defined these methods before? Just a sec?
710 01:12:30.450 --> 01:12:32.100 Sourav Mishra: Okay, no, we have not. But all right.
711 01:12:33.030 --> 01:12:37.009 Sourav Mishra: If transaction dot verify, then just return through here.
712 01:12:37.430 --> 01:12:39.219 Sourav Mishra: Are you going to implement this later?
713 01:12:41.050 --> 01:12:50.360 Sourav Mishra: Then I've self or check balance. So this check balance method. What it does is it checks. If the
714 01:12:50.520 --> 01:12:54.570 Sourav Mishra: sender has enough balance to send it to the receiver. If not, then
715 01:12:55.540 --> 01:12:58.650 Sourav Mishra: I return false. Sorry this should be right.
716 01:12:59.650 --> 01:13:02.639 Sourav Mishra: If not connection, verifier return false.
717 01:13:03.130 --> 01:13:08.559 Sourav Mishra: It's not then return false again. We're gonna implement these later.
718 01:13:10.660 --> 01:13:21.249 Sourav Mishra: So at the end. If everything is successful, like, if the transaction is successfully verified and the balance checks out like. If the sender has enough balance to send to the receiver.
719 01:13:21.360 --> 01:13:30.070 Sourav Mishra: Then again add a log, adding, and the action to pull
720 01:13:39.370 --> 01:13:43.880 Sourav Mishra: from this who love this
721 01:13:51.590 --> 01:13:55.880 Sourav Mishra: works in the form and section dot 2.
722 01:13:58.070 --> 01:14:01.539 Sourav Mishra: So we have. Yeah.
723 01:14:02.840 --> 01:14:07.279 Sourav Mishra: the log is added. Now again, we are going to do the same thing that we already did. Here.
724 01:14:07.510 --> 01:14:11.790 Sourav Mishra: Are you going to push it to the transaction pool.
725 01:14:12.050 --> 01:14:14.030 Sourav Mishra: and we are going to return to
726 01:14:16.180 --> 01:14:21.619 Sourav Mishra: so verify and check balance have not been defined yet. That's why we're getting this error. Let's define them.
727 01:14:27.200 --> 01:14:30.840 Sourav Mishra: So let's 1st define check balance so that the error will go away.
728 01:14:32.990 --> 01:14:35.619 Sourav Mishra: Check balance takes a reference to the boxing.
729 01:14:37.560 --> 01:14:40.580 Sourav Mishra: It returns the balance.
730 01:14:40.860 --> 01:14:42.910 Sourav Mishra: Oh, yeah, it also takes the address
731 01:14:43.670 --> 01:14:46.449 Sourav Mishra: of for which we are finding out the balance
732 01:14:47.600 --> 01:14:50.120 Sourav Mishra: so addresses 1% St. O
733 01:15:10.630 --> 01:15:15.020 Sourav Mishra: fine, which you want checking the balance.
734 01:15:15.450 --> 01:15:17.310 Sourav Mishra: That is 0 65.
735 01:15:17.510 --> 01:15:27.040 Sourav Mishra: So what this function basically does is it takes an address, and it takes an amount and it checks. If the address has at least this much amount present in their wallet. If it does not, then
736 01:15:27.420 --> 01:15:44.920 Sourav Mishra: I'm trying to turn on my mind so like balance equals to self.net dwellings of address.
737 01:15:46.510 --> 01:15:53.320 Sourav Mishra: and if balance greater than equal to amount, then return true.
738 01:15:54.690 --> 01:15:59.060 Sourav Mishra: Again, we get get balance is not there.
739 01:16:00.250 --> 01:16:02.500 Sourav Mishra: so let's define. Get balance. Next
740 01:16:10.070 --> 01:16:11.950 Sourav Mishra: returns the balance to me.
741 01:16:12.810 --> 01:16:14.360 Sourav Mishra: 64.
742 01:16:20.000 --> 01:16:22.620 Sourav Mishra: It takes in a reference to the server
743 01:16:24.360 --> 01:16:28.440 Sourav Mishra: and an address for which you are fetching the balance.
744 01:16:32.690 --> 01:16:35.579 Sourav Mishra: So let's send it mutable balance
745 01:16:35.880 --> 01:16:45.439 Sourav Mishra: equal to 0. So how we're going to do this is, we're gonna query the blockchain. And we're going to query every block of the blockchain, and wherever this address appears
746 01:16:45.570 --> 01:16:51.200 Sourav Mishra: we are gonna check. What is the opening and closing balance? Basically, and then
747 01:16:53.300 --> 01:17:01.300 Sourav Mishra: add it to the balance that you have defined above this new balance, and then return that so
748 01:17:01.470 --> 01:17:15.660 Sourav Mishra: for block and self blockchain, so for blocks in the blockchain and for transaction, and
749 01:17:16.170 --> 01:17:20.620 Sourav Mishra: blocked of transaction, because transactions is also a vector
750 01:17:21.750 --> 01:17:25.410 Sourav Mishra: so we're checking each transaction. And if transaction dot from address
751 01:17:26.630 --> 01:17:29.679 Sourav Mishra: equals to the address that we have passed here.
752 01:17:30.440 --> 01:17:37.179 Sourav Mishra: Then sorry it's not from address extended to address. Yeah.
753 01:17:37.630 --> 01:17:49.490 Sourav Mishra: if transaction to address is equal to the address that we have passed here, that is, if the recipient is the address that we are looking the balance for, then add the amount to the balance
754 01:17:58.560 --> 01:17:59.840 Sourav Mishra: extended amount
755 01:18:05.600 --> 01:18:06.520 Sourav Mishra: they're
756 01:18:09.680 --> 01:18:18.929 Sourav Mishra: transaction. Dot from address is equal to the address that means, if you have sent some money, then you should. Your balance is going to be deducted.
757 01:18:20.420 --> 01:18:26.030 Sourav Mishra: So this is the simpler way to do this, but this might result in
758 01:18:26.210 --> 01:18:31.319 Sourav Mishra: underflow and overflow. So it's better to use saturating sub.
759 01:18:45.430 --> 01:18:47.845 Sourav Mishra: And then finally, the last thing, if
760 01:18:49.790 --> 01:18:53.709 Sourav Mishra: the block minus address is the address that we have given.
761 01:18:53.810 --> 01:18:56.550 Sourav Mishra: or that the address is for the address which we're querying for.
762 01:18:56.770 --> 01:19:02.360 Sourav Mishra: then add a reward for mining the block. Let's say it can be any arbitrary reward that you can set
763 01:19:02.960 --> 01:19:08.190 Sourav Mishra: It should be actually handled dynamically in real chains. But since it's a mocking. It's
764 01:19:08.380 --> 01:19:11.409 Sourav Mishra: set 20 coins as the bulk mining reward.
765 01:19:13.890 --> 01:19:17.180 Sourav Mishra: And then, at the end of everything, just return the balance
766 01:19:19.730 --> 01:19:23.260 Sourav Mishra: so to quickly go through what we have done here is
767 01:19:23.740 --> 01:19:28.369 Sourav Mishra: we are running a loop through the blockchain, through every block.
768 01:19:28.570 --> 01:19:33.179 Sourav Mishra: and for every block. We are running a loop through all the transactions that are present in the block
769 01:19:33.350 --> 01:19:39.879 Sourav Mishra: and checking. If the address is receiver, then we are adding the balance to the address.
770 01:19:40.410 --> 01:19:45.600 Sourav Mishra: and if we if the address is a sender, then you're separating the balance.
771 01:19:45.830 --> 01:19:56.039 Sourav Mishra: and at the end of everything, adding and subtracting in a loop. If the block minus address is same as the address that we have passed here. Then you're adding an additional 20,
772 01:19:56.290 --> 01:19:58.230 Sourav Mishra: because that's the block mining reward.
773 01:19:58.840 --> 01:20:02.130 Gabor Szabo: Shouldn't that that ad also be saturating ad.
774 01:20:04.108 --> 01:20:09.859 Sourav Mishra: There's a a really low chance that it's gonna be an overflow because it's U 64.
775 01:20:10.710 --> 01:20:14.419 Sourav Mishra: But ideally, yes, it should be a saturating area. You're correct.
776 01:20:14.710 --> 01:20:39.099 Gabor Szabo: And and what happens really, if if the saturating sub so what have what will happen? Really if you have? I don't know. 20 in the balance. And and they are, you're subtracting 30. Okay? So the saturating at at the sub will give you the the sub. Now the sub the the from the sender. So it will get you to to 0. Right?
777 01:20:39.660 --> 01:20:42.079 Gabor Szabo: If you yeah. But.
778 01:20:42.080 --> 01:20:46.389 Sourav Mishra: Ideally that should not happen because we have defined a check balance function here.
779 01:20:46.640 --> 01:21:01.570 Sourav Mishra: So any transaction that would render your amount to go into render your balance to go into negative will not be accepted, because for every transaction that you make it is firsthand checked. Whether or not you have enough balance in your account to send a particular amount.
780 01:21:01.990 --> 01:21:02.680 Gabor Szabo: Okay.
781 01:21:03.170 --> 01:21:03.969 Sourav Mishra: So unless you know.
782 01:21:03.970 --> 01:21:10.389 Gabor Szabo: No, no need for the saturating sub right, because because this is already protected here.
783 01:21:11.290 --> 01:21:14.680 Sourav Mishra: Just a follow back just for the sake of writing safe code.
784 01:21:15.110 --> 01:21:25.870 Gabor Szabo: Okay, no, no problem. One of the one of the main, I mean, I came from Perl and Python programming. And this saturating, saturating sub.
785 01:21:26.040 --> 01:21:39.450 Gabor Szabo: They all all look nice. But it's always a question. Okay, okay? Then, what do you do? What do you do? If if how do you handle? I mean, there is okay. So your your code didn't crash. But still you have something you have to deal with.
786 01:21:39.660 --> 01:21:40.295 Gabor Szabo: Right.
787 01:21:40.930 --> 01:21:46.609 Sourav Mishra: This actually is more relevant when you are adding a balance, because balance adding has a chance of being overflowed.
788 01:21:46.950 --> 01:21:51.420 Sourav Mishra: So if the balance is overflowing. Then you can just say it's U. 64 of Max.
789 01:21:54.170 --> 01:21:54.860 Gabor Szabo: Yeah.
790 01:21:55.750 --> 01:21:57.280 Sourav Mishra: I mean, we can put this here.
791 01:22:01.840 --> 01:22:02.600 Gabor Szabo: Okay.
792 01:22:04.400 --> 01:22:06.539 Sourav Mishra: Is there something wrong? Is this not.
793 01:22:10.700 --> 01:22:11.819 Gabor Szabo: What did it say?
794 01:22:13.320 --> 01:22:16.529 Sourav Mishra: It said, need to add it for.
795 01:22:18.230 --> 01:22:23.709 Gabor Szabo: Oh, because it doesn't know what is the type? Okay, it needs to know the exact integer type.
796 01:22:26.440 --> 01:22:31.060 Gabor Szabo: So why is it not knowing what is the the amount is?
797 01:22:32.370 --> 01:22:33.170 Sourav Mishra: Okay, so.
798 01:22:33.230 --> 01:22:35.710 Gabor Szabo: I could say explicitly that it's U. 64.
799 01:22:35.890 --> 01:22:38.110 Sourav Mishra: Yeah, all right.
800 01:22:38.950 --> 01:22:44.700 Sourav Mishra: So we can add that. And when it is saturated. So the I think you're gonna get something like this.
801 01:22:44.930 --> 01:22:49.860 Sourav Mishra: Oh, 2, 64 of Max is what you're gonna get. If it is saturated.
802 01:22:54.830 --> 01:22:56.190 Sourav Mishra: you are on mute.
803 01:22:59.650 --> 01:23:01.080 Sourav Mishra: you are mute, Gabur.
804 01:23:05.080 --> 01:23:18.419 Gabor Szabo: Right? Yeah, I just keep clicking on new. Sorry so noises I might make. You're not not disrupting. So so that that's fine. So I mean, U, 64 is big, so it won't really happen, probably.
805 01:23:18.540 --> 01:23:43.620 Gabor Szabo: but on. But but still, at the end, you we decided that it's saturating. Add, because it's we. If we have 20 left, and and we add 30, we don't want it to overflow right. But but we still we added only 20, and this this subtracted from the other person. 30. So still we still had some
806 01:23:45.370 --> 01:23:54.669 Gabor Szabo: right. So so probably the the the bond that is checking the balance needs to also. So you probably also need to check whether it won't overflow
807 01:23:54.820 --> 01:24:01.839 Gabor Szabo: the other one right? And and you you would need to stop the the transaction
808 01:24:02.450 --> 01:24:04.660 Gabor Szabo: if if it would overflow right.
809 01:24:06.020 --> 01:24:16.229 Sourav Mishra: Yeah, I actually, you should do that, because if it overflows, then the money that you are sending that is kind of wasted. So it's deducted from your account, but it's not deposited in their account.
810 01:24:16.480 --> 01:24:20.709 Gabor Szabo: Yeah, I'm just trying to to think through how these things.
811 01:24:21.530 --> 01:24:37.360 Gabor Szabo: how how you really really use the saturating add and saturating. So not just here in general terms, right? Because it's so. It's fine that it doesn't doesn't crash. But it still generates you. Invalid data or incorrect data, not not invalid. Right?
812 01:24:38.060 --> 01:24:38.630 Sourav Mishra: Yeah.
813 01:24:39.300 --> 01:24:47.230 Gabor Szabo: Yeah, okay, go ahead. Just no. No problem. Okay. You're not really built something that it's going to be in production tomorrow.
814 01:24:47.770 --> 01:24:52.039 Sourav Mishra: Yeah. So it's a good point. So I'm just mentioning it here that add other things, add also
815 01:25:03.500 --> 01:25:04.279 Sourav Mishra: on it.
816 01:25:05.250 --> 01:25:12.870 Sourav Mishra: So we have check balance, and we have good balance. Now let's add these functions. So check balance is already there. But we just need to get the
817 01:25:13.690 --> 01:25:16.719 Sourav Mishra: arguments correct. So I'll just put them here.
818 01:25:22.710 --> 01:25:23.949 Sourav Mishra: This is going to.
819 01:25:23.950 --> 01:25:25.639 Gabor Szabo: Remove the types. Yeah, yeah.
820 01:25:25.640 --> 01:25:31.619 Sourav Mishra: Yeah, this is going to be transaction from. And this is going to be transaction or amount.
821 01:25:32.510 --> 01:25:33.990 Sourav Mishra: Yeah, that checks out.
822 01:25:37.220 --> 01:25:38.810 Sourav Mishra: It doesn't need these yet
823 01:25:44.150 --> 01:25:46.449 Sourav Mishra: interaction a month.
824 01:25:49.170 --> 01:25:50.650 Sourav Mishra: Something is wrong again.
825 01:25:55.280 --> 01:25:56.800 Sourav Mishra: expecting Sdr.
826 01:25:59.220 --> 01:26:09.039 Gabor Szabo: Hmm, like expecting an str and u, 64. And and what is this from? Does it define?
827 01:26:09.210 --> 01:26:11.920 Gabor Szabo: Yeah, yeah, just the Ampersand was missing.
828 01:26:12.110 --> 01:26:12.680 Sourav Mishra: Yeah.
829 01:26:13.680 --> 01:26:22.289 Sourav Mishra: So now, the only undefined thing here is verify. But that's all right, because that's defined under the implementation of transactions, not for blockchain.
830 01:26:22.720 --> 01:26:25.320 Sourav Mishra: So our blockchain implementation is essentially complete.
831 01:26:25.970 --> 01:26:30.080 Sourav Mishra: We wrote all the functions that we need to write, or did I miss something?
832 01:26:30.470 --> 01:26:34.399 Sourav Mishra: Oh, wait! Oh, you missed one function, my bias Commissioner, mind function.
833 01:26:34.980 --> 01:26:37.670 Sourav Mishra: So how do you mind the pending transactions?
834 01:26:39.890 --> 01:26:43.450 Sourav Mishra: So let's call it 9 pending transactions
835 01:26:47.330 --> 01:26:50.409 Sourav Mishra: inverted, so that on. So that on
836 01:26:54.945 --> 01:26:56.700 Sourav Mishra: option of block.
837 01:26:57.980 --> 01:27:01.650 Sourav Mishra: That is these transactions on mine. And now you have this block
838 01:27:02.070 --> 01:27:03.869 Sourav Mishra: with the transition that you got mine.
839 01:27:05.410 --> 01:27:06.336 Sourav Mishra: So if
840 01:27:07.480 --> 01:27:13.890 Sourav Mishra: self dot transaction. Pool is empty, then return none, because there are no transactions to mine in the pool, because it's empty.
841 01:27:14.200 --> 01:27:24.440 Sourav Mishra: But if it is not, then let transactions going to back off and action.
842 01:27:25.920 --> 01:27:32.890 Sourav Mishra: We need to explicitly define this type because we're going to do some iterator and collect stuff. So we need to know what we're exactly collecting into.
843 01:27:33.350 --> 01:27:35.909 Sourav Mishra: Hence the expected definition for work of transaction.
844 01:27:36.420 --> 01:27:39.770 Sourav Mishra: Then we're going to write self of transaction pool.
845 01:27:40.330 --> 01:27:43.240 Sourav Mishra: So from the pool, we are going to train.
846 01:27:46.280 --> 01:27:48.010 Sourav Mishra: and we are going to collect.
847 01:27:50.590 --> 01:27:59.640 Sourav Mishra: So drain is essentially how do I say it? It's a Dk method
848 01:28:06.040 --> 01:28:10.920 Sourav Mishra: question will itself, and minus public key.
849 01:28:20.140 --> 01:28:26.300 Sourav Mishra: So this brings the transaction pool of everything, and then it collects that and wraps it up in a backup.
850 01:28:28.100 --> 01:28:29.550 Sourav Mishra: and then let's mine it.
851 01:28:29.780 --> 01:28:33.610 Sourav Mishra: So you'll say previous block
852 01:28:36.450 --> 01:28:40.059 Sourav Mishra: equals to self dot chain dot last.
853 01:28:42.320 --> 01:28:47.550 Sourav Mishra: and since it returns an option, we can just use the custom map operator rather than 4 should be unwrapping it.
854 01:28:48.900 --> 01:28:52.730 Sourav Mishra: And then, let's say, mute block. This is going to be the current block.
855 01:28:55.120 --> 01:29:02.099 Sourav Mishra: We need this previous block because our current block needs to have the previous blocks has. That's why we queried the current block the previous block.
856 01:29:02.450 --> 01:29:04.909 Sourav Mishra: And now let's create the new block
857 01:29:14.740 --> 01:29:16.129 Sourav Mishra: for readability.
858 01:29:16.860 --> 01:29:22.290 Sourav Mishra: Previous block is just previous previous assets, as previous blocks has.
859 01:29:24.120 --> 01:29:25.710 Sourav Mishra: And we're gonna clone it.
860 01:29:44.750 --> 01:29:47.980 Sourav Mishra: Oh, wait. It's not a struct definition. It's just this, okay
861 01:29:48.230 --> 01:29:53.169 Sourav Mishra: for transactions. We have the transactions already. We just drain them from the transaction pool.
862 01:29:53.560 --> 01:30:01.720 Sourav Mishra: and for the index we are going to do previous block of index last one.
863 01:30:02.510 --> 01:30:07.359 Sourav Mishra: So the index of the new block is basically the one added to the index of the previous block
864 01:30:07.910 --> 01:30:12.600 Sourav Mishra: and the transactions. We are retaining it from the pool and adding it there
865 01:30:14.100 --> 01:30:19.230 Sourav Mishra: and then we are setting the minus address. So block dot minor equals to.
866 01:30:20.420 --> 01:30:22.230 Sourav Mishra: Again we are doing it.
867 01:30:22.830 --> 01:30:25.969 Sourav Mishra: We're converting the public key or public key into a string type.
868 01:30:27.150 --> 01:30:32.590 Sourav Mishra: So minus of dot surrealization.
869 01:30:35.370 --> 01:30:41.370 Sourav Mishra: And then self dot chain, dot, push the block, or
870 01:30:42.630 --> 01:30:46.309 Sourav Mishra: now we are adding the block that we just created here to the chain.
871 01:30:46.970 --> 01:30:51.650 Sourav Mishra: And finally, you're returning some block the block that you just added to the chain you're returning that.
872 01:30:53.090 --> 01:30:58.819 Sourav Mishra: So this completes our mind pending transaction method also. So what we did here 1st was we checked. If the pool was empty.
873 01:30:59.220 --> 01:31:01.489 Sourav Mishra: and if it was empty, then it would turn none.
874 01:31:01.680 --> 01:31:06.300 Sourav Mishra: and next, if it was not empty, then you fetch the transactions that are in the pool.
875 01:31:06.730 --> 01:31:11.800 Sourav Mishra: and then we check. If the previous blog, it exists, and
876 01:31:12.180 --> 01:31:21.030 Sourav Mishra: if it exists, then if it's the previous block, and then you create the current block with the data that you fetch from the previous block and the transactions that you drain from the pool.
877 01:31:21.680 --> 01:31:23.890 Sourav Mishra: and then you add the minus address.
878 01:31:24.720 --> 01:31:27.529 Sourav Mishra: And finally, after doing that, you push the block.
879 01:31:33.570 --> 01:31:34.969 Sourav Mishra: No doubts. Yeah, I hope.
880 01:31:46.760 --> 01:31:48.296 Sourav Mishra: And so let's proceed.
881 01:31:51.410 --> 01:31:54.900 Gabor Szabo: It looks good for so far. What? What I understand.
882 01:31:57.800 --> 01:31:59.469 Sourav Mishra: Okay, then we can proceed.
883 01:32:02.790 --> 01:32:06.130 Sourav Mishra: We are at the last stages of our blockchain.
884 01:32:06.770 --> 01:32:08.899 Sourav Mishra: We only need to define 2 more traits
885 01:32:09.140 --> 01:32:13.190 Sourav Mishra: and 2 more implementations. We need to implement 2 more implementation for 2 more types.
886 01:32:14.260 --> 01:32:17.729 Sourav Mishra: So let's implement transaction the big boy
887 01:32:22.880 --> 01:32:26.580 Sourav Mishra: for transaction. There is or constructor.
888 01:32:26.690 --> 01:32:29.819 Sourav Mishra: As usual, it's gonna return itself.
889 01:32:31.720 --> 01:32:38.220 Sourav Mishra: And it's going to take prompt, which is an Ampersand address.
890 01:32:38.730 --> 01:32:45.279 Sourav Mishra: And it's gonna take out 2, which is the receiver's address in string.
891 01:32:45.580 --> 01:32:47.479 Sourav Mishra: And then it's gonna take the amount
892 01:32:47.960 --> 01:32:51.810 Sourav Mishra: because the other things we can calculate. But these things you need as the user input
893 01:32:54.400 --> 01:32:57.300 Sourav Mishra: so that's there and then return itself.
894 01:32:58.870 --> 01:33:02.610 Sourav Mishra: So from it's from.to string
895 01:33:03.630 --> 01:33:06.809 Sourav Mishra: and to sing to the tuition
896 01:33:08.230 --> 01:33:11.149 Sourav Mishra: amount can be used as is because it's
897 01:33:11.440 --> 01:33:16.430 Sourav Mishra: already in the right format and then, timestamp, we're gonna do some
898 01:33:17.190 --> 01:33:24.860 Sourav Mishra: really weird stuff here. So we are, gonna do system time of now
899 01:33:28.100 --> 01:33:40.480 Sourav Mishra: then, duration of since unix people. So unix people is something we are importing above this
900 01:33:41.370 --> 01:33:44.400 Sourav Mishra: system time and unix report. All come from here.
901 01:33:46.020 --> 01:33:51.009 Sourav Mishra: If you do time, and then don't expect it.
902 01:33:51.900 --> 01:33:55.909 Sourav Mishra: Some random message, let's say invalid time or something.
903 01:33:58.860 --> 01:34:08.890 Sourav Mishra: And finally, as seconds, that gives us our timestamp in the desired format
904 01:34:09.890 --> 01:34:15.269 Sourav Mishra: and signature, since there is none, so far, so signature is going to be just an empty laptop.
905 01:34:17.030 --> 01:34:21.830 Sourav Mishra: and there we have a new translation object return using the new function.
906 01:34:25.070 --> 01:34:28.980 Sourav Mishra: Right? So once this is done. The next thing to implement is
907 01:34:30.570 --> 01:34:39.460 Sourav Mishra: the message to sign, so we'll call it good signing message.
908 01:34:41.030 --> 01:34:47.360 Sourav Mishra: And so the message is going to be a string.
909 01:34:52.970 --> 01:35:03.829 Sourav Mishra: So when signing anything you 1st hash them like. If you have a raw text message, you 1st hash the message and then you sign the hash of that message. You don't sign the message directly.
910 01:35:04.220 --> 01:35:07.970 Sourav Mishra: So like earlier, we are going to define a hazard.
911 01:35:09.410 --> 01:35:11.400 Sourav Mishra: the cycle for the 6th of noon.
912 01:35:12.300 --> 01:35:15.470 Sourav Mishra: and then we're gonna update the asset
913 01:35:18.610 --> 01:35:22.650 Sourav Mishra: before, and we're gonna use survey to string.
914 01:35:27.860 --> 01:35:34.140 Sourav Mishra: So self dot from self.to self dot amount server timestamp.
915 01:35:34.580 --> 01:35:35.990 Sourav Mishra: I need this
916 01:35:39.750 --> 01:35:42.870 Sourav Mishra: Lord untap my passwords.
917 01:35:44.960 --> 01:35:48.710 Sourav Mishra: Did I do it in the wrong place? Yeah, I did it in the wrong place.
918 01:35:50.920 --> 01:35:53.670 Sourav Mishra: Look at our credit card.
919 01:35:55.100 --> 01:35:59.789 Sourav Mishra: So finally return the hassle. But finally, whatever you finalize, return that.
920 01:36:02.760 --> 01:36:05.169 Sourav Mishra: How do you return? That you return that as a Vec.
921 01:36:08.870 --> 01:36:16.660 Sourav Mishra: I guess I messed up the return types. Here signature is a vec, so no, that's right.
922 01:36:19.340 --> 01:36:21.179 Sourav Mishra: Have it as a web of your
923 01:36:23.120 --> 01:36:26.139 Sourav Mishra: yeah. Now we're gonna sign in this wake-off, Eva.
924 01:36:27.670 --> 01:36:32.099 Sourav Mishra: So what we did here was we generated a message for us to sign.
925 01:36:32.380 --> 01:36:36.939 Sourav Mishra: And how did you do that? We created a string message
926 01:36:37.610 --> 01:36:48.819 Sourav Mishra: using certain to string, and we converted that to bytes, and we use those bytes in the hash hash them. And finally, we are returning the hash bytes as vec.
927 01:36:49.170 --> 01:36:53.169 Sourav Mishra: so basically the resultant back that we are returning. Here
928 01:36:53.310 --> 01:36:58.090 Sourav Mishra: is the final thing that we are going to sign. We're going to put our signature on.
929 01:36:59.560 --> 01:37:05.660 Sourav Mishra: So that's there. And finally, with the function verify that has been showing us, as Madam
930 01:37:08.570 --> 01:37:12.899 Sourav Mishra: Verify would return a pool, that is, if the verification is successful or not.
931 01:37:14.300 --> 01:37:22.790 Sourav Mishra: So to verify, we're gonna check. If the transaction is a faucet transaction, if it is, then just ignore it.
932 01:37:23.020 --> 01:37:26.049 Sourav Mishra: It's true always. We don't need to further verify anything
933 01:37:26.900 --> 01:37:31.659 Sourav Mishra: element. If it is not, then create an scp object.
934 01:37:33.580 --> 01:37:37.409 Sourav Mishra: So sccp 2, 56 k. 1 is the elective curve
935 01:37:43.330 --> 01:37:48.900 Sourav Mishra: that we are going to use for generating.
936 01:37:50.820 --> 01:37:51.750 Sourav Mishra: Keep it.
937 01:37:52.270 --> 01:37:53.470 Sourav Mishra: And same.
938 01:37:55.340 --> 01:37:56.410 Sourav Mishra: So
939 01:37:56.780 --> 01:38:10.900 Sourav Mishra: we are using this particular relative curve to generate our key pair. And we are using an algorithm called Ecdsa, that is based on this curve that is responsible for signing. So Ecdsa is a signing algorithm
940 01:38:12.710 --> 01:38:14.530 Sourav Mishra: that is based on the Ccp.
941 01:38:16.450 --> 01:38:20.569 Sourav Mishra: So we created an instance of this Scc type Sccp new.
942 01:38:21.620 --> 01:38:30.509 Sourav Mishra: And then we're gonna verify whether or not the public key that was sent to us
943 01:38:32.970 --> 01:38:34.209 Sourav Mishra: is valid or not.
944 01:38:34.330 --> 01:38:39.610 Sourav Mishra: So we are going to match it. X decode
945 01:38:43.670 --> 01:38:48.830 Sourav Mishra: self dot from stuff
946 01:38:54.190 --> 01:38:58.359 Sourav Mishra: of bytes like. If we could successfully decode that.
947 01:38:58.620 --> 01:39:02.309 Sourav Mishra: then it's cool. Okay of bytes and return the bytes.
948 01:39:07.740 --> 01:39:11.750 Sourav Mishra: There is some error. Then return the error
949 01:39:16.300 --> 01:39:19.120 Sourav Mishra: exactly the time. Just use the one, macro.
950 01:39:21.750 --> 01:39:27.630 Sourav Mishra: I don't know recording public key and
951 01:39:29.210 --> 01:39:31.370 Sourav Mishra: use the error that you just got there.
952 01:39:33.500 --> 01:39:35.209 Sourav Mishra: Return falls, of course.
953 01:39:36.040 --> 01:39:36.910 Sourav Mishra: Show it off.
954 01:39:40.510 --> 01:39:41.620 Sourav Mishra: No, that's done.
955 01:39:43.410 --> 01:39:46.299 Sourav Mishra: But semicolon. Yeah, you're good to go.
956 01:39:47.190 --> 01:39:48.400 Sourav Mishra: Then. Next
957 01:39:51.880 --> 01:39:56.499 Sourav Mishra: we are going to check the validity of the public key from the public key bytes that we just received
958 01:39:57.690 --> 01:40:00.620 Sourav Mishra: so publicly equals to match.
959 01:40:02.750 --> 01:40:05.589 Sourav Mishra: There's just a lot of validation here, because these are
960 01:40:06.470 --> 01:40:14.019 Sourav Mishra: really sensitive affairs. So you're sending money. So if it doesn't go to the right place, or if it is not from the right place, then it can go and land up anywhere
961 01:40:14.150 --> 01:40:19.570 Sourav Mishra: you are, gonna lose real money. So all these checks are to ensure that you don't do. You don't lose your money.
962 01:40:24.000 --> 01:40:25.360 Sourav Mishra: Public works.
963 01:40:27.850 --> 01:40:32.950 Sourav Mishra: Okay? So if it's okay, then return the key to me.
964 01:40:37.690 --> 01:40:42.359 Sourav Mishra: If it is an error again, log a warning
965 01:40:58.480 --> 01:40:59.150 Sourav Mishra: for you.
966 01:41:02.990 --> 01:41:04.139 Sourav Mishra: the 10 points.
967 01:41:08.260 --> 01:41:18.990 Sourav Mishra: Yeah. Public key validation is done here. So at least after this point, we are sure that the public key that is sending this transaction is actually a valid public key.
968 01:41:24.320 --> 01:41:26.710 Sourav Mishra: Now let's proceed to signing the transaction.
969 01:41:27.630 --> 01:41:30.500 Sourav Mishra: or at least verifying the sign of the transaction
970 01:41:33.810 --> 01:41:36.279 Sourav Mishra: signature equals to
971 01:41:44.780 --> 01:41:47.570 Sourav Mishra: Cdsa. This is the algorithm that I talked about.
972 01:41:50.370 --> 01:41:51.100 Gabor Szabo: Sorry.
973 01:41:52.470 --> 01:41:53.140 Sourav Mishra: Sorry.
974 01:41:53.400 --> 01:41:55.219 Gabor Szabo: Yeah, you did you ask something?
975 01:41:55.510 --> 01:42:00.720 Sourav Mishra: Oh, no, no, no. I'm saying that this issue here is the algorithm that I talked about. This thing's algorithm here
976 01:42:01.110 --> 01:42:02.150 Sourav Mishra: and signing.
977 01:42:02.400 --> 01:42:05.429 Sourav Mishra: So this is the algorithm that is used for signatures.
978 01:42:05.810 --> 01:42:06.540 Gabor Szabo: Okay.
979 01:42:07.910 --> 01:42:09.939 Sourav Mishra: From compact
980 01:42:13.950 --> 01:42:16.080 Sourav Mishra: self dot signature.
981 01:42:21.150 --> 01:42:28.669 Sourav Mishra: So what I am doing here is basically converting the signature from whatever type I had defined
982 01:42:28.780 --> 01:42:33.679 Sourav Mishra: to the actual sequencer type that is defined by Ecpc for further processing.
983 01:42:37.170 --> 01:42:44.859 Sourav Mishra: Then I'm gonna create the message again, because it's a good practice to create the signing message on your end also before verifying
984 01:42:46.200 --> 01:42:49.620 Sourav Mishra: the signature, and then a flare.
985 01:42:51.710 --> 01:42:52.620 Sourav Mishra: Sure
986 01:43:13.090 --> 01:43:15.729 Sourav Mishra: data probability is kind of really smart like. It
987 01:43:16.470 --> 01:43:21.089 Sourav Mishra: suggests almost the exact correct thing almost all the time.
988 01:43:28.250 --> 01:43:33.590 Sourav Mishra: Then I'm gonna return the verification result after signature.
989 01:43:41.080 --> 01:43:43.699 Sourav Mishra: I'll take the message.
990 01:43:43.920 --> 01:43:48.259 Sourav Mishra: I think it will be confused with necessity. So let's call this MSG,
991 01:43:51.310 --> 01:43:55.039 Sourav Mishra: and so so do you have done your signature
992 01:43:56.580 --> 01:44:00.910 Sourav Mishra: and the public key. And finally, if it is okay and put
993 01:44:02.780 --> 01:44:05.919 Sourav Mishra: rationally, return false. If none of these were
994 01:44:07.080 --> 01:44:14.329 Sourav Mishra: then it's false by default, so the transition verification is not a success solved by default.
995 01:44:17.470 --> 01:44:22.059 Sourav Mishra: Alright, the transaction implementation is also done, so is there any doubts? Are there any doubts.
996 01:44:26.580 --> 01:44:28.040 Gabor Szabo: Not from me.
997 01:44:30.180 --> 01:44:35.460 Sourav Mishra: I'll just go through the verify function again. So you are verifying. If it's a posture transaction, then you're skipping it.
998 01:44:35.670 --> 01:44:41.230 Sourav Mishra: then you are decoding the public key bytes, and you are checking if the public key is valid or not.
999 01:44:42.840 --> 01:44:45.230 Sourav Mishra: and then, finally, you are checking the signature.
1000 01:44:45.410 --> 01:44:47.640 Sourav Mishra: So you are creating a sequencer type.
1001 01:44:47.770 --> 01:44:50.060 Sourav Mishra: And then you are also getting the message.
1002 01:44:50.820 --> 01:44:58.400 Sourav Mishra: And then you are constructing a message type that is defined by Sccp. Using your string message that you just constructed.
1003 01:45:00.590 --> 01:45:07.819 Sourav Mishra: and once you are done with constructing the signature and the message, you are finally verifying that against the public key.
1004 01:45:09.800 --> 01:45:17.090 Sourav Mishra: So you verify the sign which you sign something using your private key, but you verify that using your public key.
1005 01:45:19.760 --> 01:45:23.120 Sourav Mishra: So if this verification is successful, it means you are the one who signed it.
1006 01:45:24.440 --> 01:45:25.250 Gabor Szabo: Okay.
1007 01:45:28.890 --> 01:45:33.612 Sourav Mishra: And finally, the last thing that we need to implement is our blockchain server.
1008 01:45:35.560 --> 01:45:40.760 Sourav Mishra: So we're gonna create a blocks and server type. I think we created this earlier? Not we're not creating a type.
1009 01:45:41.400 --> 01:45:47.959 Sourav Mishra: Yeah, we have the type already. Blockchain server that takes a blockchain. That is, our communities of a blockchain and blockchain. Is this
1010 01:46:01.080 --> 01:46:02.990 Sourav Mishra: so? Both function. New
1011 01:46:42.850 --> 01:46:45.620 Sourav Mishra: constructor is also done.
1012 01:46:47.120 --> 01:46:50.839 Sourav Mishra: Finally, the last thing that is left to implement is the
1013 01:46:52.620 --> 01:46:57.550 Sourav Mishra: service. This particular blockchain service like the Rpc. Service for our blockchain server.
1014 01:46:58.280 --> 01:47:02.729 Sourav Mishra: So our blockchain server needs to expose Rpc. Endpoints for our client to connect.
1015 01:47:03.010 --> 01:47:06.990 Sourav Mishra: and the Rpc. Service is defined in this protobuf file.
1016 01:47:07.930 --> 01:47:19.410 Sourav Mishra: So we need to implement this particular thing, this blockchain service. It's not a trait yet. It's just a service according to the protocol file. But since we are using tonic to compile, we already have a trait with the same name
1017 01:47:19.580 --> 01:47:25.729 Sourav Mishra: that has these same methods, a method called summit transaction method called, Get balance and method called request faucet.
1018 01:47:26.100 --> 01:47:30.630 Sourav Mishra: So you're just going to implement that trade phone also
1019 01:47:48.700 --> 01:47:55.040 Sourav Mishra: is going to be an Asynct tape by tonic. So a required macro
1020 01:48:09.250 --> 01:48:10.119 Sourav Mishra: and she
1021 01:48:13.640 --> 01:48:18.869 Sourav Mishra: connection add transaction. I'll just open this side by side.
1022 01:48:24.690 --> 01:48:26.560 Sourav Mishra: and I'll zoom out just a bit.
1023 01:48:28.590 --> 01:48:34.170 Sourav Mishra: So the methods we have on us are submit transaction, get balance and request faucet.
1024 01:48:34.270 --> 01:48:36.750 Sourav Mishra: The 1st method is going to be submit transaction.
1025 01:48:42.280 --> 01:48:45.060 Sourav Mishra: and it's going to take a self.
1026 01:48:45.250 --> 01:48:46.680 Sourav Mishra: That's the 1st parameter.
1027 01:48:47.480 --> 01:48:58.469 Sourav Mishra: And then there's gonna be requested, which is of type the best and go to a transaction.
1028 01:48:59.120 --> 01:49:02.479 Sourav Mishra: So these are the types that we have implemented.
1029 01:49:02.670 --> 01:49:05.540 Sourav Mishra: we have imported basically from above.
1030 01:49:05.970 --> 01:49:10.059 Sourav Mishra: So we have a request response and status from panic.
1031 01:49:10.360 --> 01:49:13.360 Sourav Mishra: And we have prototransaction from blockchain.
1032 01:49:14.610 --> 01:49:16.749 Sourav Mishra: which is the module we have just defined above
1033 01:49:24.840 --> 01:49:34.650 Sourav Mishra: some transaction, and it returns reserve of response.
1034 01:49:41.300 --> 01:49:48.560 Sourav Mishra: We got some a response and status.
1035 01:49:58.640 --> 01:49:59.726 Sourav Mishra: So let
1036 01:50:03.720 --> 01:50:09.620 Sourav Mishra: transaction equals to request log into enough.
1037 01:50:10.380 --> 01:50:16.520 Sourav Mishra: So this into inner, is again something that is given to us by by tonic.
1038 01:50:16.670 --> 01:50:27.639 Sourav Mishra: I have not defined this anywhere. So this into Nr, basically gives us the message. So if I don't put into enough if you can, you can see the type. The type is of request.
1039 01:50:27.980 --> 01:50:36.040 Sourav Mishra: and then the generic type. T. So in our case, the generic type T is transaction. So it has 3 things, 2 of which I don't really care about.
1040 01:50:36.420 --> 01:50:43.039 Sourav Mishra: But you can see, all of these fields are private fields, so there is no way for me to directly access the message. Field
1041 01:50:43.430 --> 01:50:45.080 Sourav Mishra: asses because it's private.
1042 01:50:46.420 --> 01:50:52.740 Sourav Mishra: So there is a function. There's a method exposed that called that's called in trainer. So I'm gonna use that to get the message.
1043 01:50:54.680 --> 01:51:03.359 Sourav Mishra: And once I have gotten the message, I'm gonna say, like transaction equals to.
1044 01:51:04.670 --> 01:51:07.150 Sourav Mishra: I'm just gonna construct it into my own type.
1045 01:51:09.770 --> 01:51:12.369 Sourav Mishra: So from it's basically
1046 01:51:12.540 --> 01:51:19.099 Sourav Mishra: transaction.com 2 is basically transaction dot 2 amount is transaction amount. Which is that correct?
1047 01:51:19.370 --> 01:51:23.740 Sourav Mishra: And then this timestamp, I'm gonna use the one that I get from there
1048 01:51:24.160 --> 01:51:27.810 Sourav Mishra: just to ensure that these 2 things are same.
1049 01:51:28.350 --> 01:51:39.840 Sourav Mishra: because there might be a certain delay between that timestamp and the timestamp when I calculate it right now, and if they are different. Then the hash will be different, and the sign won't be verified properly.
1050 01:51:40.060 --> 01:51:44.319 Sourav Mishra: That's why I'm just gonna use the timestamp from this, the one that I'm receiving
1051 01:51:47.700 --> 01:51:48.430 Sourav Mishra: alright.
1052 01:51:49.650 --> 01:51:52.200 Sourav Mishra: Everything looks fine. I have my transition object now.
1053 01:51:53.050 --> 01:52:01.780 Sourav Mishra: So I'm gonna say, let new chain equals to self dot blockchain.
1054 01:52:02.800 --> 01:52:07.365 Sourav Mishra: and I'm gonna put a mutex lock on this, so that further, when I'm like
1055 01:52:08.260 --> 01:52:11.380 Sourav Mishra: I'm going to modify the chain now by adding a template. So
1056 01:52:12.260 --> 01:52:17.660 Sourav Mishra: I am putting a lock here so that only I can modify it like this thread can modify it, not anyone else.
1057 01:52:18.680 --> 01:52:22.430 Sourav Mishra: Then I'm gonna share alert success.
1058 01:52:24.250 --> 01:52:29.750 Sourav Mishra: It was to change or add transaction. And then in the transaction that I just created above
1059 01:52:30.170 --> 01:52:33.709 Sourav Mishra: don't necessarily need to clone it, because I'm not going to use it anywhere downstairs.
1060 01:52:34.860 --> 01:52:35.660 Sourav Mishra: So yeah.
1061 01:52:39.280 --> 01:52:51.510 Sourav Mishra: so far, I created a mutex log. And I added my transaction to the gym, and I got a success result that could either be true or false, based on the success of me. Get adding the transaction to the gym.
1062 01:52:52.970 --> 01:52:56.150 Sourav Mishra: And finally, I'll create the return type. That is
1063 01:53:00.680 --> 01:53:06.179 Sourav Mishra: again, this response and everything just to remind you it comes from tonic, not something that we have defined by ourselves.
1064 01:53:10.080 --> 01:53:14.829 Sourav Mishra: Success is this value, and the last thing is message.
1065 01:53:25.740 --> 01:53:27.410 Sourav Mishra: We can close this for now.
1066 01:53:29.440 --> 01:53:33.620 Sourav Mishra: so message is based on the success. So if the transaction is successful, then it's
1067 01:53:33.810 --> 01:53:37.920 Sourav Mishra: added to the pool, or will it say transaction accepted.
1068 01:53:38.190 --> 01:53:40.840 Sourav Mishra: and if it is not, then we can say transaction failed.
1069 01:53:42.540 --> 01:53:46.019 Sourav Mishra: So that is our 1st function, the submit transaction function.
1070 01:53:48.240 --> 01:53:53.410 Sourav Mishra: The next layer is get balance. This is a really simple function.
1071 01:53:54.710 --> 01:53:58.989 Sourav Mishra: Okay, balance. Just query the chain and get the balance.
1072 01:54:00.700 --> 01:54:05.290 Sourav Mishra: And then this will return something like above. So let's copy this for simplicity.
1073 01:54:06.860 --> 01:54:07.770 Sourav Mishra: Okay.
1074 01:54:11.550 --> 01:54:18.870 Sourav Mishra: so forget balance. The return type is not transaction response, whether it is balances once.
1075 01:54:23.260 --> 01:54:26.499 Sourav Mishra: And this is also pretty similar. So let's copy it.
1076 01:54:28.240 --> 01:54:33.800 Sourav Mishra: It takes an instance to sell, and the request is not this but balance request?
1077 01:54:37.799 --> 01:54:42.920 Sourav Mishra: Where am I getting these things? The balance request, balance, response, and everything. I'm just getting this from here.
1078 01:54:43.520 --> 01:54:48.480 Sourav Mishra: The protocol file. So balance request is already there. Balance response is also already there.
1079 01:54:50.600 --> 01:54:53.280 Sourav Mishra: Transaction response. As you can see, it's already there.
1080 01:54:55.540 --> 01:55:03.110 Sourav Mishra: And I'm just type aliasing this as photo transaction, because this is also transaction here.
1081 01:55:03.340 --> 01:55:09.060 Sourav Mishra: And my local type transaction is also called transaction, just to avoid confusion. I'm calling it floater transaction
1082 01:55:09.970 --> 01:55:15.979 Sourav Mishra: and proto transaction comes from here so you can see transaction as proto transaction. I'm importing it as that
1083 01:55:20.230 --> 01:55:21.880 Sourav Mishra: right? Oh, no.
1084 01:55:22.640 --> 01:55:28.320 Sourav Mishra: Try this function. Let address Equals to
1085 01:55:30.990 --> 01:55:35.689 Sourav Mishra: request Dot into enough, because we need the message, the inner message, that's right.
1086 01:55:37.090 --> 01:55:39.080 Sourav Mishra: And then, finally, we need the address
1087 01:55:43.160 --> 01:55:50.910 Sourav Mishra: which chain equals to self, dot blockchain, dot low dot of it
1088 01:55:56.300 --> 01:56:04.410 Sourav Mishra: same as before, because we need a mutex lock and let balance
1089 01:56:05.300 --> 01:56:10.989 Sourav Mishra: equals to chain dot get balance. This get balance is the method that we just defined above
1090 01:56:11.160 --> 01:56:15.170 Sourav Mishra: for our login implementation, and it takes an address.
1091 01:56:16.480 --> 01:56:19.689 Sourav Mishra: So I got the balance now, and I'll just construct the response.
1092 01:56:22.030 --> 01:56:27.229 Sourav Mishra: And this is so you can see the return type is satisfied. Date expects
1093 01:56:27.648 --> 01:56:30.600 Sourav Mishra: response type in the okay. So that's what I gave him.
1094 01:56:33.490 --> 01:56:36.660 Sourav Mishra: And this balance is the balance that I'm fetching from the chain.
1095 01:56:39.580 --> 01:56:47.140 Sourav Mishra: There is one last method that's the last and the last thing in the project itself. It's the request faucet method.
1096 01:56:48.280 --> 01:56:51.340 Sourav Mishra: It's going to be a little long. But bear with me
1097 01:56:53.360 --> 01:56:57.380 Sourav Mishra: so, as usual, let's just copy this. It's easier that way.
1098 01:56:58.180 --> 01:57:03.810 Sourav Mishra: and then put it here, and let's call this request faucet
1099 01:57:05.884 --> 01:57:09.670 Sourav Mishra: before diving into this. Do you have any doubts.
1100 01:57:14.040 --> 01:57:15.260 Gabor Szabo: What is this?
1101 01:57:15.480 --> 01:57:17.460 Gabor Szabo: Have a more general question later on.
1102 01:57:19.467 --> 01:57:20.389 Sourav Mishra: Sorry come again.
1103 01:57:20.390 --> 01:57:24.160 Gabor Szabo: I'll have another question, but once once you finish it.
1104 01:57:25.180 --> 01:57:26.480 Sourav Mishra: Okay? Sure.
1105 01:57:34.730 --> 01:57:40.519 Sourav Mishra: So this is going to be of type faucet request. And this is going to be of type. Faucet response.
1106 01:57:41.410 --> 01:57:48.930 Sourav Mishra: Again, faucet request and faucet response is something we're getting from the profile, request and response.
1107 01:57:51.670 --> 01:57:56.429 Sourav Mishra: And then status is something we have from tonic itself. We're importing that from tonic itself
1108 01:57:59.510 --> 01:58:00.420 Sourav Mishra: all right.
1109 01:58:01.750 --> 01:58:03.349 Sourav Mishra: Where did that cool yep.
1110 01:58:05.730 --> 01:58:13.079 Sourav Mishra: So like address again, equals to request or entering network address?
1111 01:58:13.220 --> 01:58:19.409 Sourav Mishra: Because we need the address, because this is the address to which we are gonna send the coins after the faucet transaction.
1112 01:58:21.180 --> 01:58:25.419 Sourav Mishra: and then we'll create a transaction
1113 01:58:26.820 --> 01:58:29.889 Sourav Mishra: like we did here. So let's just copy and paste. This.
1114 01:58:35.220 --> 01:58:39.470 Sourav Mishra: so from address is going to be faucet address
1115 01:58:40.290 --> 01:58:43.809 Sourav Mishra: to address is going to be the address that we just received.
1116 01:58:44.110 --> 01:58:47.160 Sourav Mishra: or the address that we just got from the message.
1117 01:58:48.810 --> 01:58:55.069 Sourav Mishra: They want to do it and amount is something that we can
1118 01:58:56.420 --> 01:58:59.848 Sourav Mishra: defined by ourselves. So this is hard coded. Let's say, it's
1119 01:59:00.260 --> 01:59:03.279 Sourav Mishra: 1,400 coins, any arbitrary amount.
1120 01:59:04.010 --> 01:59:11.189 Sourav Mishra: And, Pakistan, anybody, we're gonna use the same thing as this.
1121 01:59:12.590 --> 01:59:13.320 Sourav Mishra: No
1122 01:59:23.760 --> 01:59:29.170 Sourav Mishra: signature is going to be empty because it's for your transaction.
1123 01:59:33.190 --> 01:59:33.860 Sourav Mishra: No.
1124 01:59:37.040 --> 01:59:39.179 Sourav Mishra: discharge the rules, and
1125 01:59:43.650 --> 01:59:47.249 Sourav Mishra: yep, we also constructed a transaction here. The 1st transaction.
1126 01:59:47.410 --> 01:59:53.240 Sourav Mishra: Now let's add it to the chain to the transaction pool whoops
1127 01:59:54.960 --> 02:00:00.079 Sourav Mishra: join equals to copy and paste this.
1128 02:00:00.900 --> 02:00:03.360 Sourav Mishra: then copy and paste this whole thing starting from there
1129 02:00:13.390 --> 02:00:18.620 Sourav Mishra: and then we're going to mine a block the transaction
1130 02:00:22.040 --> 02:00:26.830 Sourav Mishra: faucet transactions are mined immediately, at least in our journey.
1131 02:00:30.290 --> 02:00:40.970 Sourav Mishra: So we're gonna create another scp object like we did earlier, then create a new keypad.
1132 02:00:43.340 --> 02:00:45.159 Sourav Mishra: Let's call it faucet key.
1133 02:01:06.920 --> 02:01:12.220 Sourav Mishra: So ideally, this should actually come from your env files, because this will not change.
1134 02:01:12.480 --> 02:01:15.860 Sourav Mishra: But every time you request for 4 C transaction. This kind of changes.
1135 02:01:27.990 --> 02:01:28.989 Sourav Mishra: I'll block it.
1136 02:01:31.380 --> 02:01:34.750 Sourav Mishra: 10 dot, 9 pending transactions.
1137 02:01:36.040 --> 02:01:41.130 Sourav Mishra: Use the faucet key that we just created.
1138 02:01:45.460 --> 02:01:50.820 Sourav Mishra: If it is successful, then add a log that the faucet transaction was successful, and it was mine successful
1139 02:01:52.010 --> 02:01:53.010 Sourav Mishra: doing good.
1140 02:01:56.980 --> 02:02:05.989 Sourav Mishra: Poster blog no cash, only a good price.
1141 02:02:08.070 --> 02:02:10.310 Sourav Mishra: It's blog, dot hash?
1142 02:02:14.190 --> 02:02:15.890 Sourav Mishra: Then send a response.
1143 02:02:59.190 --> 02:03:02.770 Sourav Mishra: So this is covered for the success part.
1144 02:03:03.250 --> 02:03:07.279 Sourav Mishra: What if this fails? What if we're not able to mine the transaction? What if we're not able to get a block.
1145 02:03:07.550 --> 02:03:11.009 Sourav Mishra: So for that, I'm just gonna create an error response
1146 02:03:17.990 --> 02:03:19.780 Sourav Mishra: supposed to copy this thing.
1147 02:03:24.660 --> 02:03:33.020 Sourav Mishra: There is no faucet amount in our case. So let's say, start code 1,400 always works. Yeah.
1148 02:03:36.790 --> 02:03:42.639 Sourav Mishra: mount in 0 because it's already failed.
1149 02:03:43.270 --> 02:03:49.470 Sourav Mishra: So let's surface is false among this 0, let's say is, is.
1150 02:03:54.460 --> 02:03:56.830 Sourav Mishra: I need to process once it request.
1151 02:03:59.440 --> 02:04:00.280 Sourav Mishra: That's it.
1152 02:04:01.900 --> 02:04:05.529 Sourav Mishra: So we are essentially done with the chain. Let me just check if
1153 02:04:12.550 --> 02:04:13.210 Sourav Mishra: hmm!
1154 02:04:13.750 --> 02:04:24.619 Sourav Mishra: I think we had a missing implementation. Someone difficulty is, where did they unload?
1155 02:04:31.820 --> 02:04:32.570 Sourav Mishra: Room?
1156 02:04:33.330 --> 02:04:36.720 Sourav Mishra: Probably missed something somewhere. Yeah, we missed these things
1157 02:04:37.660 --> 02:04:40.640 Sourav Mishra: and the start method. Obviously, those things you may have missed.
1158 02:04:41.040 --> 02:04:42.729 Sourav Mishra: So let's implement them quickly
1159 02:04:46.710 --> 02:04:53.139 Sourav Mishra: supplemented for consensus. And okay, the start method. So
1160 02:04:55.120 --> 02:04:57.320 Sourav Mishra: how do we start it? We're going to spawn a new thread
1161 02:04:57.850 --> 02:05:08.549 Sourav Mishra: because one thread is responsible. The main thread is responsible for running the Glp server is responsible for mining.
1162 02:05:12.010 --> 02:05:14.820 Sourav Mishra: So we sponsored.
1163 02:05:20.320 --> 02:05:24.860 Sourav Mishra: It's getting annoying. Yeah, and then assume move
1164 02:05:25.910 --> 02:05:29.950 Sourav Mishra: again. It's all syntax for asynchronous coding and rust
1165 02:05:37.710 --> 02:05:45.050 Sourav Mishra: and Sccp equals to Ccp. 2, 56 a 1,
1166 02:05:45.860 --> 02:05:48.190 Sourav Mishra: and for you on your Ccp object?
1167 02:05:49.590 --> 02:05:51.820 Sourav Mishra: Then you're gonna generate a key.
1168 02:05:53.790 --> 02:05:55.830 Sourav Mishra: It's going to the public key.
1169 02:05:57.520 --> 02:06:04.530 Sourav Mishra: It goes to the net repair. Let me start this, then I'm gonna log.
1170 02:06:05.360 --> 02:06:06.780 Sourav Mishra: The manage address.
1171 02:06:10.650 --> 02:06:11.820 Sourav Mishra: My name?
1172 02:06:25.140 --> 02:06:28.290 Sourav Mishra: Probably not super nice
1173 02:06:32.420 --> 02:06:35.520 Sourav Mishra: something else playing with this. I don't need this.
1174 02:06:47.090 --> 02:06:49.259 Sourav Mishra: Next, we're gonna loop.
1175 02:06:50.200 --> 02:06:56.780 Sourav Mishra: because it's a continuous process checking for transactions in the transaction pool. They keep on checking, and if you find transactions, then you mine them.
1176 02:06:58.860 --> 02:07:01.030 Sourav Mishra: So the loop. Let's create a scope.
1177 02:07:01.460 --> 02:07:03.699 Sourav Mishra: Let's let mute Jane
1178 02:07:07.130 --> 02:07:10.520 Sourav Mishra: goes to acquire a mutex lock.
1179 02:07:18.530 --> 02:07:24.599 Sourav Mishra: If chain dot transaction pool has a set number of transactions only, then start mining.
1180 02:07:25.000 --> 02:07:33.850 Sourav Mishra: So for testing purposes we can set the limit to one as in
1181 02:07:34.860 --> 02:07:43.700 Sourav Mishra: if there is one single transaction in the transaction pool, then lately.
1182 02:08:14.880 --> 02:08:19.289 Sourav Mishra: and then once you mind a walk, sleep for some time 5 seconds, for example.
1183 02:08:22.610 --> 02:08:24.810 Sourav Mishra: who's we are done now?
1184 02:08:25.500 --> 02:08:30.420 Sourav Mishra: So just to go over this method again, it spawns a thread. It creates a new minor key.
1185 02:08:30.780 --> 02:08:35.819 Sourav Mishra: and it starts mining. It starts listening to the transaction pool in a loop.
1186 02:08:35.980 --> 02:08:42.830 Sourav Mishra: and when the number of transactions in the pool is greater than one, or you can say, if it is at least one.
1187 02:08:42.930 --> 02:08:48.329 Sourav Mishra: then the minor it drains all the transactions from the pool and starts mining them.
1188 02:08:48.730 --> 02:08:52.539 Sourav Mishra: If you want it to be strictly greater than one, then you can just remove the equal to, and it will work.
1189 02:09:00.790 --> 02:09:06.900 Sourav Mishra: Yeah, this part is unimplemented. Okay, number. Now, this needs some login
1190 02:09:09.590 --> 02:09:16.220 Sourav Mishra: transaction. Verification failed. This also needs some login information, valid information. Correct?
1191 02:09:16.950 --> 02:09:19.170 Sourav Mishra: So yeah, our blockchain code is now ready.
1192 02:09:20.440 --> 02:09:21.960 Sourav Mishra: Anyone has any doubts.
1193 02:09:29.690 --> 02:09:30.700 Gabor Szabo: But for me.
1194 02:09:33.070 --> 02:09:35.120 Sourav Mishra: You had a question somewhere else, right?
1195 02:09:36.970 --> 02:09:44.109 Gabor Szabo: Yeah, but it's it's like a more more generic question. So we implement you implemented that a blockchain
1196 02:09:44.360 --> 02:09:47.040 Gabor Szabo: system for for sending money.
1197 02:09:47.260 --> 02:09:48.830 Gabor Szabo: And and
1198 02:09:49.390 --> 02:09:57.181 Gabor Szabo: and I was wondering, Okay, what? Why do? Why do we need another one? Why do we need a platform to implement these
1199 02:10:00.030 --> 02:10:07.890 Gabor Szabo: the next? Another way to to to send money. If you have already a number of these blockchains for
1200 02:10:08.020 --> 02:10:13.799 Gabor Szabo: for sending money, so would would a company just implement one, and then then use it, for I don't know
1201 02:10:14.670 --> 02:10:16.059 Gabor Szabo: their clients.
1202 02:10:17.936 --> 02:10:18.770 Sourav Mishra: Send it.
1203 02:10:19.197 --> 02:10:26.040 Gabor Szabo: Let's say a bank will will open one for themselves. What was the idea behind it?
1204 02:10:28.170 --> 02:10:34.473 Sourav Mishra: Yeah. So blockchains are not exactly used only for sending and receiving money. There are a lot of other implications also, like
1205 02:10:35.427 --> 02:10:39.400 Sourav Mishra: Real world, asset, exchange and everything. Name a few.
1206 02:10:40.040 --> 02:10:46.729 Sourav Mishra: But why should you create a new blockchain? You should create a new blockchain if you are creating something unique.
1207 02:10:47.140 --> 02:10:55.379 Sourav Mishra: This is just a general explanation of how a blockchain functions in general. This is not actually a production ready, unique blockchain that people are going to use tomorrow like you said.
1208 02:10:55.700 --> 02:10:57.240 Gabor Szabo: Right, yeah, yeah, yeah.
1209 02:10:57.240 --> 02:11:04.430 Sourav Mishra: Yeah, this was just created to explain people how the internals of a blockchain work, how the components of a blockchain can be coded using rushed.
1210 02:11:04.730 --> 02:11:09.129 Sourav Mishra: Of course it has room for a lot of improvement, but this is like
1211 02:11:09.300 --> 02:11:15.590 Sourav Mishra: kind of like stripping down a fully functional blockchain that is out there in production to its grassroots, level.
1212 02:11:16.110 --> 02:11:18.540 Gabor Szabo: Okay, I'll ask it a different way. Okay.
1213 02:11:18.760 --> 02:11:27.080 Gabor Szabo: I totally understand. Why would someone learn how to write a web application? Okay? Because you need web applications for
1214 02:11:28.000 --> 02:11:29.820 Gabor Szabo: millions of companies.
1215 02:11:30.130 --> 02:11:31.090 Gabor Szabo: Okay.
1216 02:11:31.290 --> 02:11:32.280 Sourav Mishra: Okay.
1217 02:11:32.560 --> 02:11:36.140 Gabor Szabo: But I I don't understand.
1218 02:11:36.660 --> 02:11:43.590 Gabor Szabo: but I don't think that the 1,000, even thousands of companies will want to have their own blockchain.
1219 02:11:43.880 --> 02:11:46.759 Gabor Szabo: Yeah, company don't usually have their own logins.
1220 02:11:47.262 --> 02:11:50.399 Sourav Mishra: So companies don't usually have their own blockchains.
1221 02:11:50.400 --> 02:11:56.650 Gabor Szabo: Exactly so. So you have very few blockchains in the world at the end, right.
1222 02:11:56.650 --> 02:11:59.179 Sourav Mishra: Do have a lot of blockage in the world. But.
1223 02:11:59.180 --> 02:12:04.739 Gabor Szabo: How how many I mean hundreds, thousands, or or how many do you think there there are.
1224 02:12:06.560 --> 02:12:11.800 Sourav Mishra: it could be hundreds could be thousands. I'm not really sure. But it's a big number. It's not like.
1225 02:12:11.800 --> 02:12:24.919 Gabor Szabo: That's fine. That's fine. But it's not like a million. So the question is, okay. So I see lots of ads, for example, for peeping people
1226 02:12:25.060 --> 02:12:30.129 Gabor Szabo: writing code. Okay? So programmers who know blockchain, whatever level.
1227 02:12:30.240 --> 02:12:32.589 Gabor Szabo: what kind of work do they do? I mean.
1228 02:12:33.170 --> 02:12:35.540 Gabor Szabo: they don't implement new blockchains, right?
1229 02:12:36.170 --> 02:12:43.709 Sourav Mishra: No, they build blockchains from scratch, like I am a core protocol engineer. So basically, that's what I do. That's my job. Building blockchains from scratch.
1230 02:12:43.900 --> 02:12:52.909 Sourav Mishra: And we implement basically different protocols that are not pre-existing. Or we implement protocols that are suited to our needs.
1231 02:12:54.560 --> 02:12:54.980 Gabor Szabo: Do this.
1232 02:12:55.920 --> 02:13:05.770 Sourav Mishra: We implement basically custom blockchains. So if you have a business, need you implement a blockchain based on that particular need which no other public blockchain offers. You.
1233 02:13:06.430 --> 02:13:11.445 Gabor Szabo: Right? Okay, but what? What? What? Yeah. So, but what we are saying here is that,
1234 02:13:12.720 --> 02:13:18.130 Gabor Szabo: there is not like in the millions. It's like the thousands. The number of these blockchains.
1235 02:13:18.450 --> 02:13:28.660 Sourav Mishra: Yeah, it generally depends on a use case. So if you already have a blockchain that so kind of caters to some use case, then you don't really need to create a new blockchain that does the same thing.
1236 02:13:29.220 --> 02:13:31.695 Gabor Szabo: Okay. But do do people,
1237 02:13:32.650 --> 02:13:44.699 Gabor Szabo: Keep improving blockchain? So what is what is a besides what you do? Okay, so so that's fine. There are a few people like you who build blockchains from scratch
1238 02:13:45.730 --> 02:13:59.059 Gabor Szabo: right? But there are lots of jobs out there. It seems to be that the one of the most popular job titles in for us developers or the areas of of development is somewhere in in blockchain.
1239 02:13:59.950 --> 02:14:02.810 Gabor Szabo: So what what do these do all these developers do.
1240 02:14:04.155 --> 02:14:07.114 Sourav Mishra: It's not only building blockchains from scratch like there are
1241 02:14:07.900 --> 02:14:18.510 Sourav Mishra: plethora of job roles available. One of the most popular ones is a smart contract developer. So basically, you build smart contracts and deploy them to already existing blocks and platforms.
1242 02:14:19.210 --> 02:14:25.749 Sourav Mishra: Okay, ethereum uses solid contracts. Our polka dot can use. Let's say, inc, smart contracts. For example.
1243 02:14:26.917 --> 02:14:33.360 Sourav Mishra: anchor contracts. So that is, I think, by far the most popular role. If you talk about jobs.
1244 02:14:33.840 --> 02:14:35.570 Sourav Mishra: smart contact development.
1245 02:14:36.040 --> 02:14:36.800 Gabor Szabo: Okay.
1246 02:14:36.800 --> 02:14:45.019 Sourav Mishra: And then the there's a d app developer like who builds mobile and web applications on top of existing blockchains and use them as the backend.
1247 02:14:46.660 --> 02:14:51.900 Sourav Mishra: So it's not always only building blockchains from scratch, but also building on top of blockchains that do exist.
1248 02:14:52.740 --> 02:14:53.460 Gabor Szabo: Okay.
1249 02:14:53.460 --> 02:14:57.999 Sourav Mishra: But you can think of it as a different discipline of blockchains. Software blockchains.
1250 02:14:59.010 --> 02:14:59.660 Gabor Szabo: Right?
1251 02:15:00.610 --> 02:15:01.560 Gabor Szabo: Okay.
1252 02:15:06.050 --> 02:15:07.070 Gabor Szabo: okay.
1253 02:15:07.830 --> 02:15:12.480 Sourav Mishra: Okay. So I think we are done with the implementation. Let's try to run and see if it works.
1254 02:15:12.750 --> 02:15:13.170 Gabor Szabo: Okay.
1255 02:15:13.590 --> 02:15:14.730 Sourav Mishra: I do hope it works.
1256 02:15:22.610 --> 02:15:30.200 Sourav Mishra: This is the command to run it cross our fingers if it works.
1257 02:15:30.890 --> 02:15:31.610 Gabor Szabo: Mom.
1258 02:15:32.600 --> 02:15:37.129 Sourav Mishra: Okay. So now we have blockchain running on this address on this port.
1259 02:15:38.240 --> 02:15:44.559 Sourav Mishra: Again. It's hard coded, so it should not be hard coded. It should be fetching it from some envy or something, but it's hard coded. So let's just
1260 02:15:44.780 --> 02:15:50.219 Sourav Mishra: move on with that, and I will share my a wallet screen. No.
1261 02:16:08.560 --> 02:16:10.940 Sourav Mishra: I hope you can see my screen.
1262 02:16:13.353 --> 02:16:17.620 Gabor Szabo: Yes, I can see your editor right now.
1263 02:16:18.770 --> 02:16:20.590 Sourav Mishra: Let's open the wallet screen. Now.
1264 02:16:20.590 --> 02:16:21.439 Gabor Szabo: Hello! Everyone.
1265 02:16:22.740 --> 02:16:28.290 Sourav Mishra: So this is my wallet code that I wrote. It basically is a client that connects with the blockchain.
1266 02:16:28.660 --> 02:16:29.390 Gabor Szabo: Okay.
1267 02:16:29.590 --> 02:16:50.690 Sourav Mishra: Yeah, so there are various files here. So the command file basically defines the available commands like new command creates a new wallet list command. Let's list from the wallets that are available already. Balance command fetches the balance from the blockchain for that particular address and send command sends transactions, and the faucet, command, request money from the faucet.
1268 02:16:52.440 --> 02:16:56.339 Sourav Mishra: and then I have an errors. File where I have defined a custom error for wallet error.
1269 02:16:56.680 --> 02:17:04.960 Sourav Mishra: So these are the various errors that are defined as an enum, and then I have also implemented the corresponding string representation by using implementing the display
1270 02:17:05.090 --> 02:17:07.889 Sourav Mishra: trade for them for this particular webinar.
1271 02:17:08.209 --> 02:17:20.819 Sourav Mishra: and then I have added some conversions because I want to return only wallet errors. So even if it is an I/O error, I am converting it to some form of wallet error, so that I can just return wallet error. I don't need to cater 2 different types of errors.
1272 02:17:21.250 --> 02:17:28.319 Sourav Mishra: and then at the end I have a custom result type that returns a generic T when it's all right.
1273 02:17:28.420 --> 02:17:44.940 Sourav Mishra: But if it is an error, then it returns wallet error always. So this is the reason why I needed to do all of this, because these are potentially the errors that I will run into in my code, and if I do, then how do I convert them into wallet errors? So I have written the form. I implemented, the form tricks for all these particular errors.
1274 02:17:45.209 --> 02:17:49.000 Sourav Mishra: If it is strategation, error, then it's disemparts error for the volatile.
1275 02:17:49.240 --> 02:17:53.790 Sourav Mishra: If it is tonic, transfer error, then it is volatile connection failed error, and so on and so forth.
1276 02:17:55.660 --> 02:18:00.849 Sourav Mishra: And in the main file, I have basically implemented the command. So like, what happens if you.
1277 02:18:01.549 --> 02:18:07.339 Sourav Mishra: if a command is create wallet, then what should happen if a command is list wallet, then what should happen? So on and so forth.
1278 02:18:07.969 --> 02:18:13.919 Sourav Mishra: In the models I have defined some types. One of the types is keypad, that is, a private key and public keypad.
1279 02:18:14.160 --> 02:18:19.360 Sourav Mishra: And the other type is wallets. That is basically a hash map of a wallet name
1280 02:18:19.670 --> 02:18:21.439 Sourav Mishra: map to a key pair
1281 02:18:23.360 --> 02:18:29.799 Sourav Mishra: in the profile. It's again just pop more blockchain that we had defined earlier in our blockchain. Also.
1282 02:18:30.219 --> 02:18:35.529 Sourav Mishra: it just includes the photograph into our code and creates a model out of it.
1283 02:18:36.660 --> 02:18:42.004 Sourav Mishra: Storage dot rs, this load function it
1284 02:18:43.160 --> 02:18:50.850 Sourav Mishra: checks the memory, and if the wallet file already exists, then it loads it into memory, and the save function basically writes to the wallet file.
1285 02:18:52.070 --> 02:18:57.719 Sourav Mishra: The add wallet function adds a new wallet to the already existing wallet file. So wallet file looks something like this.
1286 02:18:58.410 --> 02:19:01.990 Sourav Mishra: It's adjacent, basically. So I've already created 2 wallets for you and me.
1287 02:19:06.040 --> 02:19:11.629 Sourav Mishra: And the get wallet function gets a wallet by the name from its collection.
1288 02:19:12.620 --> 02:19:16.259 Sourav Mishra: And the resolve address basically takes a name or key.
1289 02:19:16.520 --> 02:19:20.560 Sourav Mishra: and if the name matches with the wallet's name, then it returns it. If the
1290 02:19:20.940 --> 02:19:24.669 Sourav Mishra: publicly matches with the sum of I mean
1291 02:19:25.170 --> 02:19:30.289 Sourav Mishra: any of these public keys, then it returns. The public key doesn't matter what name it is.
1292 02:19:30.980 --> 02:19:41.639 Sourav Mishra: And finally, if it is not a wallet that we have saved on us, even by name or by the public key, if it is. But if it is any generic general valid public key.
1293 02:19:41.910 --> 02:19:45.690 Sourav Mishra: then also you can return it. It's valid. If it is neither, then return one.
1294 02:19:48.000 --> 02:19:53.756 Sourav Mishra: And finally, this wallet is the grpc implementation, the client implementation. This calls the functions
1295 02:19:54.340 --> 02:19:59.109 Sourav Mishra: so these there are some Async functions like this, get balance which calls the
1296 02:19:59.420 --> 02:20:03.269 Sourav Mishra: Rpc. Get balance from the on the on. The blockchain gets it on the blockchain.
1297 02:20:04.720 --> 02:20:08.040 Sourav Mishra: So yeah, that is the entirety of the wallet application.
1298 02:20:14.160 --> 02:20:15.360 Sourav Mishra: So let's
1299 02:20:16.280 --> 02:20:25.379 Sourav Mishra: done this. So actually, this is also available as upgrade on greater diode. So I have it installed. The package is called mock wallet.
1300 02:20:27.720 --> 02:20:31.549 Sourav Mishra: So I'm not gonna run the code. But I'm gonna use the no correct command.
1301 02:20:35.510 --> 02:20:36.430 Gabor Szabo: Okay.
1302 02:20:37.010 --> 02:20:38.489 Sourav Mishra: So let's create a new wallet.
1303 02:20:39.450 --> 02:20:42.130 Sourav Mishra: just to show how to create wallets on you.
1304 02:20:42.610 --> 02:20:46.010 Sourav Mishra: Then let's give some name. Let's say, quote, madam.
1305 02:20:48.270 --> 02:20:52.770 Sourav Mishra: and it says, a new wallet code method has been created, and if we check the wallets file.
1306 02:20:53.300 --> 02:20:57.669 Sourav Mishra: we can see that support map, and already there, with a corresponding publicly and privately.
1307 02:20:59.710 --> 02:21:04.049 Sourav Mishra: So now let's try to send some money first.st Take. Let's take a balance.
1308 02:21:06.800 --> 02:21:10.390 Sourav Mishra: VLNG. For let's check it for Gabor.
1309 02:21:11.106 --> 02:21:17.760 Sourav Mishra: As expected, you have 0 coins because it's a new model we have not yet transacted, or you have not received anything on the faucet.
1310 02:21:21.300 --> 02:21:23.770 Sourav Mishra: So let's request some money from the faucet.
1311 02:21:29.530 --> 02:21:34.919 Sourav Mishra: And this works, yeah. So you receive 1,400 coins in your volume.
1312 02:21:35.050 --> 02:21:40.470 Sourav Mishra: And if we go back to the blocks and implementation, we can see that some blogs are added.
1313 02:21:40.870 --> 02:21:49.060 Sourav Mishra: so adding transactions from faucet to pool, it's added 1,400 transactions. 1,400 coins are added, and then the faucet block is also created
1314 02:21:49.430 --> 02:21:57.369 Sourav Mishra: with the Hesters, so like whatever you do here, the blockchain gets it because there are Grpc connections.
1315 02:21:58.680 --> 02:21:59.510 Gabor Szabo: Okay.
1316 02:22:01.140 --> 02:22:02.710 Sourav Mishra: So now let's try to send money.
1317 02:22:03.510 --> 02:22:04.780 Gabor Szabo: Show me the balance.
1318 02:22:05.390 --> 02:22:06.669 Gabor Szabo: Show me my balance.
1319 02:22:06.970 --> 02:22:09.419 Sourav Mishra: Definitely, do you want it?
1320 02:22:10.660 --> 02:22:15.780 Gabor Szabo: Okay, we have 2, 8, 00 points. It twice.
1321 02:22:16.870 --> 02:22:17.740 Gabor Szabo: Yeah. Good.
1322 02:22:18.020 --> 02:22:21.320 Sourav Mishra: Now let's try to transfer some money, so send.
1323 02:22:22.230 --> 02:22:26.480 Sourav Mishra: is it? Let's in the board thought of.
1324 02:22:27.590 --> 02:22:29.240 Sourav Mishra: I'm gonna take most of your money.
1325 02:22:30.890 --> 02:22:33.700 Gabor Szabo: Well you were, for you were hard, so you could skip.
1326 02:22:34.720 --> 02:22:36.349 Sourav Mishra: Okay, fine. I'll take the 500,
1327 02:22:38.570 --> 02:22:44.579 Sourav Mishra: and so you can see. I entered the name Sora, but it said Invalid, because there is no address for Sara.
1328 02:22:44.790 --> 02:22:47.620 Sourav Mishra: and you can see that is called Saurav with Saurav Mishra.
1329 02:22:47.740 --> 02:22:49.430 Sourav Mishra: So we have to enter the name.
1330 02:22:50.060 --> 02:22:52.509 Sourav Mishra: and you can see transaction has been sent successfully.
1331 02:22:52.750 --> 02:22:57.400 Sourav Mishra: Okay, you can see it added the transaction to the pool.
1332 02:22:58.080 --> 02:22:58.660 Gabor Szabo: Yeah.
1333 02:22:59.930 --> 02:23:04.239 Sourav Mishra: So if you add one more transaction, let's say, do the same thing. But with this coins now
1334 02:23:05.370 --> 02:23:09.549 Sourav Mishra: the transaction is again sent successfully, and this is added.
1335 02:23:09.940 --> 02:23:11.990 Sourav Mishra: and a new block is mined.
1336 02:23:13.280 --> 02:23:13.860 Gabor Szabo: Yeah.
1337 02:23:16.470 --> 02:23:20.539 Sourav Mishra: So that is the whole implementation of our blockchain and the client.
1338 02:23:26.270 --> 02:23:27.290 Gabor Szabo: Okay.
1339 02:23:30.080 --> 02:23:32.689 Sourav Mishra: So there are like a lot of areas to improve on.
1340 02:23:33.370 --> 02:23:40.429 Sourav Mishra: But this is like I could strip it down to the least complexity, and I came up with this.
1341 02:23:41.730 --> 02:23:43.810 Gabor Szabo: Very nice, nice.
1342 02:23:43.810 --> 02:23:55.849 Sourav Mishra: I had removed some more features, then it might have become a really boring blockchain. So I tried to include all aspects of the blockchain while keeping it simple. So this is I could. What I could come up with. It took longer than expected to explain it and write it down.
1343 02:23:56.090 --> 02:23:58.169 Sourav Mishra: but I hope at least it was worth it.
1344 02:23:58.780 --> 02:24:04.059 Gabor Szabo: Yeah, yeah, I think I think I I learned a lot. I still need to. I mean, I
1345 02:24:04.670 --> 02:24:12.160 Gabor Szabo: still need to go over for over this again and again, I guess, until I it sinks in. But yeah, thank you very much.
1346 02:24:15.200 --> 02:24:21.549 Sourav Mishra: You can follow the read me, there are some areas where you can contribute. So if you like this project, then you can contribute this to this project.
1347 02:24:21.880 --> 02:24:30.560 Sourav Mishra: So towards the end there are some, maybe enhancements that can be done. There are some concession mechanisms that can be added like we have not added, for proof of stake or proof of authority, something like that.
1348 02:24:32.030 --> 02:24:41.769 Gabor Szabo: and then you made the changes you made here in this branch are they all available available on the main branch or, did you push this out, or.
1349 02:24:41.770 --> 02:24:52.160 Sourav Mishra: It's all available in the main branch, so I try to make it same as the main branch. So people who are following live can also be benefited, while people who are not following live and checking it out from the Github, they can also benefit.
1350 02:24:52.500 --> 02:24:54.210 Sourav Mishra: Okay.
1351 02:24:54.910 --> 02:24:55.740 Gabor Szabo: Excellent.
1352 02:24:57.420 --> 02:25:01.080 Gabor Szabo: Well, thank you very much.
1353 02:25:01.340 --> 02:25:02.360 Sourav Mishra: Anyone have a doubt.
1354 02:25:05.600 --> 02:25:06.520 Sourav Mishra: something.
1355 02:25:06.810 --> 02:25:08.519 Gabor Szabo: I'm overwhelmed. So
1356 02:25:09.980 --> 02:25:20.560 Gabor Szabo: so thank you very much for this presentation, and thank you. Everyone who who stayed and and well, there were not not many questions. At the beginning we were a few.
1357 02:25:21.160 --> 02:25:31.489 Gabor Szabo: and I hope that people who watch this video enjoyed it and please like the video and follow the channel, and below the video you'll find links to
1358 02:25:31.690 --> 02:25:41.380 Gabor Szabo: to the repository as well and to to Sorab, so you can contact him if you want to. I don't know. Work with him, or just ask him questions.
1359 02:25:41.880 --> 02:25:45.320 Gabor Szabo: and I think that's it right. Anything else.
1360 02:25:45.320 --> 02:25:51.520 Sourav Mishra: I sent my telegram. Id on chat. So, Radek, if you're interested, you can contact me on telegram, and we can chat if you want to chat. Talk about this project.
1361 02:25:52.483 --> 02:26:03.539 Gabor Szabo: Excellent, so I can, whatever you you like. I can share on on this web page, or I can link to your I don't know. I'm going to link to your Linkedin page and and whatever you like. Okay.
1362 02:26:03.960 --> 02:26:05.619 Sourav Mishra: Yeah, that works. Thank you so much.
1363 02:26:05.930 --> 02:26:11.730 Gabor Szabo: Yeah, thank you very much. Okay, so thank you. Thanks everyone. And see you next time. Bye, bye.
1364 02:26:12.120 --> 02:26:12.820 Sourav Mishra: Bye, bye.
