Consensus Algorithms, Blockchain Technology and Bitcoin UCL

Consensus Algorithms, Blockchain Technology and Bitcoin UCL - by Andreas M. Antonopoulos

Рет қаралды 214,413

Күн бұрын

An academic lecture by Andreas M. Antonopoulos explaining the consensus algorithm, "Proof of Work", used by bitcoin and many other blockchains. Andreas is a UCL alum.
Chapters
0:00 Introduction
1:38 What is bitcoin?
3:07 SHA-256
21:28 Consensus rules
23:47 25 bitcoin reward
26:38 Who sets the validation rules?
28:46 Bitcoin blockchain technology explained
46:23 Other protocols for consensus
47:14 The longest chain and blocks
51:07 Bitcoin mining
53:27 How often does a fork happen?
1:06:41 Every node has to fully validate from the genesis block to today
1:08:31 Nakamoto consensus
1:09:14 Scaling other consensus algorithms
1:10:44 Consensus algorithm as a scientific discipline
1:11:51 Process consensus
1:13:02 Reference consensus
1:13:25 5 consensus constituencies
1:15:33 It's not so easy to shift consensus in bitcoin
1:17:33 How many transactions can you get done in 10 minutes?
1:21:43 Bitcoin and Moore's law
This talk was presented in collaboration with the Department of Computer Science at University College London.
If you want early-access to talks and a chance to participate in the monthly live Q&As with Andreas, become a patron: / aantonop
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Andreas M. Antonopoulos is a technologist and serial entrepreneur who has become one of the most well-known and respected figures in bitcoin.
Follow on Twitter: @aantonop / aantonop
Website: antonopoulos.com/
He is the author of two books: “Mastering Bitcoin,” published by O’Reilly Media and considered the best technical guide to bitcoin; “The Internet of Money,” a book about why bitcoin matters.
Subscribe to the channel to learn more about Bitcoin & open blockchains; click on the red bell to enable notifications about new videos!
MASTERING BITCOIN, 2nd Edition: amzn.to/2xcdsY9
Translations of MASTERING BITCOIN: bitcoinbook.info/translations...
THE INTERNET OF MONEY, v1: amzn.to/2ykmXFs
THE INTERNET OF MONEY, v2: amzn.to/2IIG5BJ
Translations of THE INTERNET OF MONEY:
Spanish, 'Internet del Dinero' (v1) - amzn.to/2yoaTTq
French, 'L'internet de l'argent' (v1) - www.amazon.fr/Linternet-large...
Russian, 'Интернет денег' (v1) - www.olbuss.ru/catalog/ekonomi...
Vietnamese, 'Internet Của Tiền Tệ' (v1) - alphabooks.vn/khi-tien-len-mang
MASTERING ETHEREUM (Q4): amzn.to/2xdxmlK
Music: "Unbounded" by Orfan ( / orfan )
Outro Graphics: Phneep (www.phneep.com/)
Outro Art: Rock Barcellos (www.rockincomics.com.br/)
Join the aantonop Channel: aantonop.io/joinaantonopyt

Пікірлер: 132

@LAsherCorson 5 жыл бұрын

Andreas, you have such a fantastic way of explaining things in the most clear, simple, precise, and non-arrogant way. People love you because you are clearly a genius but you don't make your listeners feel dumb. Bravo sir.

@andgm5209 2 жыл бұрын

Absolutely! He has a gift

@davecorley5514 2 жыл бұрын

Andreas thank you for this gem. I’m a retired engineer with enough economic mastery to figure product margins. The detail, the stories and the analogies you provide are simply wonderful. Today, I don’t think I can teach what you have taught me. But tomorrow I’ll use what you’ve taught me to take me to the next step. My trust in BTC’s code and human action on the margins continues to increase day by day. That a computer scientist who wanted to invent an interoperable solution with BTC would have to replicate its features, warts and all, is an amazing revelation. BTC’s bugs have value!

@KaizenCrypto 4 жыл бұрын

I may not have gone to college...but i have really invested in my education. This video is gold and is blessing to have available for free! Thank you

@lakshminarayanannandakumar1286 5 жыл бұрын

If you are in search for some good technical explanations about Bitcoin, this video is a must watch. Hats off to Andreas !!

@covelus 4 жыл бұрын

11:35 indeed, a8d19153 (a8d191538209e335154750d2df575b9ddfb16fc7) is the SHA-1 of "Hello! ", the SHA-256 of "Hello!" is 334d016f (334d016f755cd6dc58c53a86e183882f8ec14f52fb05345887c8a5edd42c87b7). The guy from the public executed shasum without params, which, nowadays, uses sha1 by default, the way to obtain SHA-256 is through sha256sum or shasum -a 256. Apart from that, without cleaning the new-line. The way: $ echo -n "Hello!" | sha256sum or $ echo -n "Hello!" | shasum -a 256

@umarsebyala9920 5 жыл бұрын

Watching this in 2019 gives me a real feeling of how tech evolves! This was recorded when BITCOIN CASH was still a theory without a name yet, we have two bitcoin cash now! lightning network was still alive only in theory, we have payment channels funded with 1 BTC currently and still growing! Truly bullish on the future of crypto!!💯

@marysini1391 3 жыл бұрын

Andreas the best bitcoin teacher! Calispera

@mickesvensson1703 5 жыл бұрын

Great talk and finally someone that can explain the details.

@DarrenGoulder 3 жыл бұрын

Believe me I have watched thousands of hours researching Blockchain & this is stilly he best presentation yet. 💯🙏

@EmaMazzi76 2 жыл бұрын

Best comprehensive explanation on the subject ever! Thank you

@demetrioskasabalis5536 5 жыл бұрын

Andreas is a true genius! One can easily detect that, not from his deep knowledge on the subject, but from the humility with which she shares it with others! Standing applause!

@mikegaertner4118 5 жыл бұрын

just for people who wonder, the guy in the room gave the sha-1 hash, not the sha256 hash, he run the command wrong (i guess using mac, where default is sha-1 from the shasum command)

@IC-kf4mz 5 жыл бұрын

I was wondering the same.

@IC-kf4mz 5 жыл бұрын

Exactly. These are the results in Mac: hasum

@althalusian 4 жыл бұрын

@@IC-kf4mz Thank you, that was so annoying wondering why I couldn't match the one said in the lecture, but I suspected the comments might know the reason. And so they did :)

@swapnajeet 6 жыл бұрын

Brilliant explanation. Great work Sir.

@ajinkyapande9767 5 жыл бұрын

Best video on POW on KZfaq ... Best work by Andreas

@formetoknow540 Жыл бұрын

Andreas antonopoulos is a gem we all are grateful for you

@thanasispanification 4 жыл бұрын

Great lecture. Thank you very much Andreas!

@JavedSaikia 3 жыл бұрын

Best lesson on POW! Thank you Sir 🙏🙏

@brokensteel4441 3 ай бұрын

Thank you! From Brazil! I really learn with this lesson

@habibaghasafari2237 2 жыл бұрын

I'm enjoying this in 2022. What a fantastic lecture. I wished I knew about Bitcoin back then.

@Larry21924 5 ай бұрын

This is beyond my expectations. I read a book with a similar theme, and it exceeded all my expectations. "Game Theory and the Pursuit of Algorithmic Fairness" by Jack Frostwell

@inthezone9817 3 жыл бұрын

Andreas I miss your videos and the times you went all over the world ! Nowadays the crypto space has evolved so much since you've started spreading the word ! Also many new projects have emerged from ADA's and OGN's NFT crazy sales all the way to stable coins with a yield like OUSD ! No better moment to be into crypto then now ! I came here thanks to you and I am here to stay !

@robertowalsh5707 2 жыл бұрын

Great lecturer, knowledgeable on the subject and knows how to explain. I want to be like him. Thanks.

@aantonop 2 жыл бұрын

So nice of you. Thank you!

@javiervelazquez8971 2 жыл бұрын

Andreas is a Master!, thank you!!!

@trapOrdoom 4 жыл бұрын

This was a fantastic lecture. Would be blessed to see one in person.

@benstolman4073 6 жыл бұрын

One of my heroes

@juergenaushusum2587 5 жыл бұрын

Best Tube ever!!! I learned so much

@dasmith2737 3 жыл бұрын

👍

@dasmith2737 3 жыл бұрын

Agreed

@PurnamaABC 4 жыл бұрын

Thank you!!! I'm finally cleared with the proof of work.

@NaveenSwamy 2 жыл бұрын

Best video on bitcoin consensus algorith !

@chezdude3265 6 жыл бұрын

Very well done

@wisunhi77 3 жыл бұрын

This is the video that showed me the rabbit hole of Bitcoin where there was no turn back.

@opaherbert2435 2 жыл бұрын

Andreas talked about payment channels 6 years ago and now we have Lightning Network. Very good class, I learned a lot about the orphan blocks green/red chain ~0:43:00

@norrismasters2629 4 жыл бұрын

Pretty neat! Andreas. I mined bitcoin in 2013 for money without knowing what I was doing. I left the industry only to return in 2017 - I've spent last 2yr watching videos like this! I know know better. I wish I watched this before I became a BTC miner...Very good!!

@formetoknow540 Жыл бұрын

2013 woow

@sujeewae6599 3 жыл бұрын

What a detail explanation. Learn a lot

@aantonop 3 жыл бұрын

Glad it was helpful!

@ikust007 2 жыл бұрын

WoW….6 years ago. I am so far away …. Thank you Sir for leaving this on the Yt realm.

3 жыл бұрын

FANTASTIC!!!!

@davoodmobaraki Жыл бұрын

Upper of our minds. Extraordinary

@phoenixeyes7160 5 жыл бұрын

Thank you...anto...

@freedomfight1933 4 ай бұрын

Thank you

@gorunjinian 3 ай бұрын

Proof-of-Work is Beautiful, Consensus Mechanism is Beatiful. Bitcoin is Beautiful

@fyang1024 4 жыл бұрын

Hi Andreas, interestingly you mentioned the plan to increase the block size in 2016. I wonder what's your view of bitcoin cash and bitcoin cash SV?

@nicolasdemarco4288 5 жыл бұрын

Thank you Andreas for such a clear explanation! @aantonop don't you think that consensus rule about the longest chain leads to mining concentration in a certain region ? I appreciate your feedback

@soundsandambientvideos380 5 жыл бұрын

what do you think of hashgraph?

@giladbaruchian7522 2 жыл бұрын

so according to what you say it makes a lot of difference if i am near a place with a lot of mining in it because there is more chance i will be on the winning side of the fork, right ?

@ernestolombardo5811 5 жыл бұрын

Absolutely dynamite talk, at this point these more technical ones are the ones I enjoy the most.

@FareAlert 3 ай бұрын

Holy crap the levelDB error! Jeepers!

@hal9000svk 4 жыл бұрын

Awesome! Can anyone recommend another video about bitcoin which is also as technical and as long as this one?

@justinpauckert 3 жыл бұрын

The MIT lectures on bitcoin and finance is now on YT. Allthough i have to confess i found this video in search of a more technical approach, they go somewhat deep into the influence of cryptocurrencies on markets.

@mencheswest8993 5 жыл бұрын

and as i understood if you're not moving your coins during these forks, your funds are safu) right?

@zonnovate8809 5 жыл бұрын

MAX WEST Your coins are always safe from what I understand. Like he said the blockchain never forgets a transaction, it might get delayed but never lost. If you have transacted with the correct consensus rules.

@palakondarayuduuppu6420 6 жыл бұрын

what if after fork also both forks generate one more block, then what happen to transactions in orphan Block?

@mencheswest8993 5 жыл бұрын

i guess orphan txs just returned to mempool, avaiting for another miner

@RoulDukeGonzo 5 жыл бұрын

For a big transaction the recommendation is to wait for about 6 blocks

@prodipgogoi2485 6 жыл бұрын

At the time of race condition how the reward system work?

@RoulDukeGonzo 5 жыл бұрын

Race conditions are broken by the next block. This happens routinely. The mining reward can't be spent until that block is at least 100 blocks deep

@mencheswest8993 5 жыл бұрын

so all the race are for the Zeros. or any particular line of same numbers in the begining of hash. could it be a line of "1111jhdihwbvih..."? or"...ijwdhgviwfh000000000"?. I'm wondering what the reason behind chosing "zeros before hash" as a main cryteria?? is it the hadrest combination to find somehow?

@dalelinney8437 5 жыл бұрын

No harder than any other combination. The difficulty is that they have to find that and EXACTLY that, so it has to be x number of zeroes and nothing else is acceptable. If there were 1 million possible combinations, this is the only one that works, the chances are one in a million. If you changed the requirements to all 1s at the start, there's only one way of doing that, so the chances are still one in a million. Same if you chose it to be 010101010101.... Zeroes are just easy to agree on and remembered, and are kind of the "default number" in programming. (the actual chance is 2 to the power of how many zeroes the requirement is)

@dalelinney8437 5 жыл бұрын

Also, the chances I was talking about refer only to the chance of the lead numbers being zeroes. After that they may be other things. So for example 000000xyz and 000000zyx, so there may be multiple different ways of creating the right hash value, but it just has to come out with 0s at the start. 0s are just an arbitrary way of choosing a hard obstacle for people doing the computing, therefore providing proof of work.

@mencheswest8993 5 жыл бұрын

@@dalelinney8437 good explanation. Thanks)

@RoulDukeGonzo 5 жыл бұрын

It's easier to check. I e. It's it smaller than x

@sys8188 6 жыл бұрын

Interesting extreme bi-forkation event at 54:40

@davoodulhakeem9044 5 жыл бұрын

is bitcoin could be forked into post quantum cryptography

@RoulDukeGonzo 5 жыл бұрын

Yes. Andreas has vids covering the details

@IC-kf4mz 5 жыл бұрын

Recorded by IamSatoshi?

@dataecstasy 2 жыл бұрын

people who are coming 35 minutes late in the class should considered watching it on youtube.

@FareAlert 3 ай бұрын

Wow, regarding the race condition… this satoshi character was a smart feller😮

@carmendeoliveirainteglia3471 4 жыл бұрын

Andreas I have thousands of bitcoin cash in my wallet on my cellphone and I don't know how to cash out. Please help....

@scp3178 2 жыл бұрын

1000 of bitcoin would be better 😉

@donnaburns2305 5 жыл бұрын

So do the Forks keep us safe in the long run

@donnaburns2305 5 жыл бұрын

Sorry got it now

@MDSTU 2 жыл бұрын

SEMPRE ATUAL

@nosuchthing8 Жыл бұрын

What prevents a bad actor to introduce a bug by buying up the company that makes the version of C++ used in the block chain code?

@putyograsseson Жыл бұрын

open sources

@user-zf2sl4jn6o 3 жыл бұрын

34:30 consensus algorithm

@harikrishnanchandramohan4209 2 жыл бұрын

He talks exactly like Jesse Eisenberg and Christoph Waltz in Social Network.

@majiddehbi9186 4 жыл бұрын

great kecture just more deails have to be much more simplified

@MrKoijen1 5 жыл бұрын

Don't know what the guy put in his sha256 function, but it was not that phrase. A8D19 is not what I'm getting... :-)

@IC-kf4mz 5 жыл бұрын

He did she not sha256

@covelus 4 жыл бұрын

he did SHA-1 of "Hello! ", $ echo "Hello!" | shasum instead of, for example: $ echo -n "Hello!" | shasum -a 256

@covelus 4 жыл бұрын

he did SHA-1 of "Hello! ", $ echo "Hello!" | shasum instead of, for example: $ echo -n "Hello!" | shasum -a 256

@covelus 4 жыл бұрын

he did SHA-1 of "Hello! ", $ echo "Hello!" | shasum instead of, for example: $ echo -n "Hello!" | shasum -a 256

@covelus 4 жыл бұрын

he did SHA-1 of "Hello! ", $ echo "Hello!" | shasum instead of, for example: $ echo -n "Hello!" | shasum -a 256

@dpapa2175 4 жыл бұрын

I'm working on an improvement, Sha257

@FareAlert 3 ай бұрын

Holy crap, at the time, the hashrate was 500 petahashes and in 2024 it’s over 600 exahashes 😮😮😮😮

@joelwhitus7878 4 жыл бұрын

So eventually the power/energy companies will merge with “big tech” companies and compete against one another. If Bitcoin were to become a mainstream currency, where would that leave your average civilian who has no chance mining faster than the aforementioned mentioned conglomerates?

@SAL-fs1mr 3 жыл бұрын

There is always an opportunity to find a small pocket of extremely cheap energy that can be mined for bitcoin on a small scale.

@profyt7199 3 жыл бұрын

i watched half of this, now im an expert. TO THE MOON!

@narekkhachatrian9552 Жыл бұрын

What if Andreas is satoshi?

@formetoknow540 Жыл бұрын

Naah he's not he's just computer sciences who has been around since the start of the Internet and was primed when he was reading the bitcoin protocol white paper and it all clicked in a way he understood how important this technology and network was

@pwnedbythrust2959 6 жыл бұрын

Does it run of python?

@covelus 4 жыл бұрын

Pywhat? You must install Visual Basic 6 or Turbo Pascal ;P

@abbasalisu5788 Жыл бұрын

my words can't be enough to express my gratitude to you Sir. can I have your social media handle?

@Antonio-nn5ot 2 жыл бұрын

3:07 Satoshi walks in

@tolique3601 5 жыл бұрын

those guy in first row so bored. how it even possible when you attending absolutely fascinating lecture. I'm dreaming to learn this those days.

@covelus 4 жыл бұрын

probably he gave to him credits for going. I gave one lecture back in 2010 at my university about my BSc Thesis (how to create authentication systems), credited, and only a couple of mates were interested about my work. Everyone else was watching through the Window (almost no smartphones back then)

@Treece 4 жыл бұрын

Watching this in 2019 wishing i saw it in 2016 . I invest everything i make into Bitcoin and other cryptocurrencys because i know what there truly worth ! Thanks for the awesome speach man !

@formetoknow540 Жыл бұрын

Did u buy in 2109

@curtislucas8404 3 жыл бұрын

Elon musk needs to watch this.

@nbme-answers 2 жыл бұрын

0:52 start 1:36 network protocol, encryption, zero-sum game designs that change np

@azogticmettroskik8904 4 жыл бұрын

Who else fell asleep and then saw that?

@obamacare7393 4 жыл бұрын

i really love hthis vidoe found it from patreik michels channel hop[e he relpies @patrick michel

@anarchic_ramblings 4 жыл бұрын

You still have a hint of a British accent Andreas.

@PaulHusek 2 жыл бұрын

A good talk, but the statement made around 9:35-10:30 that the SHA-256 always changes for changed input is provably false. Agreed, it is difficult to find collisions, but there is no question that they do exist.

@nosuchthing8 Жыл бұрын

It's very rare

@joans.gonzalez3017 3 жыл бұрын

CWVBLOCKCHAIN in its quest to build a fast and stable bottom layer of its blockchain, CWVBLOCKCHAIN uses the consensus principle of PoST since it's bottom layer already has a consensus of ledger and storage proof.

@odilonduarte9252 5 жыл бұрын

Dr Andreas me perdoe e algo fiz centros supletivo s com problema de saúde deste criança são estudos.........se formar desocupado e algo sério livros dor cabeça ética segurança saúde costas peso desobediência e perto portão rua como chá ? Pede pedra sopa receita.😍 Hoje como pessoas com perdas de espaço aceita café?

@climatetech511 2 жыл бұрын

35:23 I bet these people got bored hearing about Bitcoin, never bought and are kicking themselves right now.

@keuba1 2 жыл бұрын

Love it. But keep it simple. You put to fillet stakes into sha256 mince grinder. Sure,you get a minced beef. Now, try it in reverse(hoping to get back to two fillet stakes). And you are fucked. No way it is possible to return to innitial state. Thats what sha256 is.

@RoulDukeGonzo 5 жыл бұрын

26:36 Who sets the validation rules? I disagree with your answer here Andreas! I think the answer is simply 'consensus' (and all that that implies). Discussing reference implementation and core implementation may be technically correct, but it's conceptually wrong. kthxbi

@neilhfrancis1334 Жыл бұрын

Questions: 1. For what single reason do our Bitcoin & BlockChain Experts give for the anonymity of their creator(s)? 2. Whatever the answer is to 1. isn’t it human nature to broadcast one’s achievements?

@LoneStarStinger 2 жыл бұрын

I remember hearing about bitcoin in 2009 when I graduated highschool and thinking it was the future and sooo cool. Then my world blew up, best friend died and I disappeared into military life. *Se La Vie*

@formetoknow540 Жыл бұрын

2009 where did u hear it in 2009

@neilhfrancis1334 Жыл бұрын

You know, I have probably the daftest recommendation* (*based on the brilliance of the presentation v my ineptitude). Time should go down, not up. The blockchains drawn “vertically propagated” instead of top to bottom (like a core drilling in Antarctica or a Family Tree) was simply not right. I think laterally most of the time, but upside down?………

@RobertReichertsutanimulli 2 жыл бұрын

content ok, presentation of the stuff to the student IMHO bad, too much oral blabla without short notes on the board. one has to record the lesson to make notes. maybe someone should gift an IPAD to that guy