The scaling part starts at 13:13

I admire that Dr Shehar Bano manages to talk about something substantial without non-functional pauses, hesitations, or saying "uhm".

She gives a good interview. Well thought out. Interview her again!

Dr. Bano gave the clearest and most succinct blockchain description and summary talk ever! Does she have other presentations you can recommend? Perhaps a sequence of videos? I would very much like to see her start her own KZfaq channel, much like her fellow Computerphile alumnus Rob Miles.

I could listen to her speak all day. Clear, conscise, informative.

Dr. Bano is smart, tells the story really clearly, and I could listen to her accent all day. But I smiled when she’d say we don’t want to get forked. No we do not!

She's very eloquent. Great interview.

This was a very good and realistic explanation. It's the first video I came across which has described things the way they are. I was hearing a lot about blockchain, and all were portraying it like it's the perfect thing. And the only thing bothering me was, how can they deal with latency so perfectly? I mean that's one of the major challenges when dealing with shared data. And if there was no problem with latency with current technology, then existing systems can also work equally well. Secondly, what about scaling? Where would all the data go? In the age of cloud, where there's a probability that even OS would be in the cloud and we'll be just holding devices, there's a concept that all the world's data would be in our systems? Not possible of course. And if only some peers will handle it, then we're again back to where we're coming from. But this video explains the goods of blockchain, and how there are some challenges which they're trying to deal with.

I've got to say, this topic is massively interesting and the video was awesome. I was totally glued to her every word. Thank you numberphile!

Nice! One of the best, well laid out explanations on blockchain that I have heard so far... for my level of understanding I mean.

To implement an electronic voting system on a blockchain infrastructure u need to address the issues 1.)the validation process of the voters and 2.)by doing that keeping the anonymity of the voters as well.

Sheharji the way you have explained, I got reminded of my friend who used to teach me in college...plain, simple and in easy language

Very fine! She seems well prepared and watches her pronounciation very carefully. I understand her by far better than some scotsman talking way too fast :-) One of the best videos lately. And actually a lot of content again (for a change ;-/ )

Just found out my .28¢ worth of bitcoin I got a while ago has turned into $8 worth. Not bad.

Love that "Practical Visual C++ 6" book on the shelf.

Very good explanation. 10/10 ! Thank you Dr. Bano!

Well presented in an easily understood manner. Very informative. Thank you!

This video has more than tripled its value over the last 15 hours.

This video is simply amazing about many of the issues which needs to be addressed due to lack of scalability of bitcoin desgin and blockchain technologies. As it passed 5 years, it could be good an update video of what has been solved or changed since then.

Bitcoin's blocksize is no longer capped at 1 MB, with SegWit update activated in Auguest the maximum possible blocksize is 4 MB, but on practice it would be close to 2 MB. We've already seen a 1.3 MB block.

fascinating and clear explanation. Keep going on this topic! would love to hear about the other decentralized consensus methods mentioned midway through.

Seriously thank you for putting up videos like this its really helpful , and the Dr explains things really well .

Simply the best video on blockchain description ever!

Yeah, let's give these "leaders" such a big stake in the system that they won't want to misbehave. That worked *so* well with banks. What could possibly go wrong?

I like to hear her talk, shes intelligent and very nice to listen to. Thanks for all the info!

Yeah, block chains scale up linearly. More transactions require bigger blocks, this is why all the focus is developing off chain settlement so that we can take 99.9% of transactions off the blockchain.

From what I remember, blockchain transparency is the issue with voting, as it makes voting traceable, eliminating the secret ballot. Of course, many attempts are being made to eliminate this problem win various ways, but this can add additional problems. For example, one proposal I just read can be taken over by only a few people organizing the vote, thus relying on them to be honest.

Great video. Really cleared my concepts.

Very clearly and beautifully explained. Thanks!

Very Informative

Very nice explaination... for convoluted concepts of BlockChain technology

do an episode on zk-Snarks next!

Great interview! I'd love to see a follow-up video. Please elaborate on how the IOTA Tangle fits in the mix. Does it solve the scalability problem? What are the new challenges we will face when using Tangle?

this video just answered all my questions about the block chain thank you

Wow stunning woman and very clear explanation of something quite complex. I've never really understood how cryptocurrencies work but this cleared up a lot.

Fantastic discussion on the topic. Thanks!

The best blockchain explanation I've seen.

awesome video on blockchain scalability. very thorough and informative! computerphile ftw 😎

I think this woman seemed a bit nervous at first, but got into it quickly! Very nice good video!

Very good explanation , thanks!

Solid explanation. Thank you.

Transactions don't include block ids (hashes) when referring to previous outputs, they include transaction ids.

There are now many competing technologies such as blockDAGs, Tangle and Hashgraph. All of which are Directed Acyclic Graphs. Tangle gets faster with scale and is only limited by bandwidth. Hashgraph has Asynchronous Byzantine level security and throughput over 250000 pre-sharding.

Excellent explanation!!

More Dr Bano!

If I pass some bitcoins to you, then why is some leader involved? I need to sign that they are now yours. Then get them added (is it this last bit, to stop people adding random stuff?). With forks, could they use merging? Could be a problem with double spending. Do coins have an ID or is there just a ledger of spends resulting in a balance?

If the question is blockchain scalability, why not discuss storage constraints? This is especially an issue with something that's transacted as often as a currency.

I think I finally understand it at last! :)

This is one of the best explanations I've seen given for Bitcoin for a general audience. For once, it seems quite accurate, compared to what I know of the system.

So the concepts are amazing, and blockchains are the first, very naive implementation of said concepts. It is essentially nothing but a linked list with a protocol layered on top to ensure tamper-proofness. Can't wait for a better implementation! Smart contracts have the potential to be completely transformative to our society!

great video, thanks to this promising scientist

What's your take on PoC (Proof of Cooperation), used by Faircoin?

So here you discuss possible improvements to the blockchain, but can these changes be implemented on existing blockchains? Or everytime you want to change the blockchain a new genesis block must be created?

Hi Im loving the video , but that pencil sound with the paper is killing me ... aggghh , i have to say i love the issue, the explanation is really clear and also love your channel. I have some questions ... if we want to have a server (database) using blockchain tech , i know it wont be a classic centralized server , but my question is ... as we put more info into the data base , the chain gets longer and harder to solve? is there a limit? ... is the limit the capacity by the minner's nodes to solve the hashes ? if the calculating capacity of the nodes get increased it makes the system could keep growing? also love to know if this system is moore secure than RSA codification, because if it is, and also is open source ... will be nasa getting really mad?

Awesome video !!

Great video, but I don't understand the comparison between Bitcoin and Visa. Bitcoin is a currency, not a bank, you can trade it directly but normally you would do it through some third-party service just like Visa or Mastercard does for the USD and other traditional currencies, this solves the latency problem.

The subject of the video is fascinating, but can we take a moment to compliment the presenter? She has such a clear way of speaking. No "uhh"s, "well"s and such. I was like she had it written beforehand and was just reading. I was listening to the video while doing the dishes, and it felt almost like an audiobook. Amazing stuff, I'd like to be this good at public speaking one day.

That was great. Thanks for sharing

The annotations at the end of the video, which link to the Krack attack and botnets, are missing. Great interview btw ^^

Finally someone actually talks about why blockchain is fundamentally bottlenecked. I have to explain this to everyone all the time. I personally don't hold out much hope for figuring out how to scale such a thing.

Clear, deep and accurate!

Very nice video!

Informative, cheers.

How do you index the blockchain so that you can quickly find all transactions involving Alice? Can this be done without every node having to store the entire blockchain?

Couldn't those "leader" nodes just be an alternating committee, and not a permanent group? That was collusion could not really be possible.

Fascinating

I wonder how the idea of a hierarchy of sharded committees works or not. Like, if the committee that handles A-F needs access to G it could pass it on to a higher committee which handles A-N, with the highest committee handling A-Z.

GREAT! THANKS FOR SHARING IT

pretty much confirmed my suspicion that the #1 problem is scalability. 7 transactions per second is indeed very very slow.

13:05 what study is she referring to?

Thats was the topic of my thesis! :D

Why not have a disposable committee? I think the instinct to trust the leaders is the problem. Instead once a result from a leader is used, blacklist that node for as long as possible. If I am being nefarious I have to wait a very long time to come become eligible again, thereby demotivating the the nefarious behavior.

There is some sort of a very high-frequency noise appearing in the sound of the video at about 4:40-4:50. Am I crazy?

They’re not, strictly-speaking, blockchains, but I wish she had discussed Directed Acyclic Graphs, which are a type of distributed ledger that do reverse the scalability problem.

Brady could you please do a video about Monero? The Monero blockchain is encrypted and that's pretty damn cool.

If you have to wait for a few blocks to be finished after you submit yours... just to know that it is final, doesn't that imply that your submission could be lost? How would this happen and isn't that a big problem?

We need scaling on second layer, sidechains => Lightning Network. Blockchain will become a settlement layer.

I heard that the Bitcoin Core team don't want to do the hard fork of 2MB block increase and want to implement the lightning network instead. How does the lightning network would actually help scale if it is a system built on top? you would still have 1 MB every 10 minutes. I agree that increasing the block to 2MB is just an immediate solution and not a long term one because in a few years we will be back to the beginning. Can you make a video on this lightning network proposal?

Great! Have been waiting for this episode

Proof of Stake blockchains scale much better than Proof of Work blockchains, because in Proof of Stake every wallet can create blocks, you don't need hashing power. But still people keep thinking that you need to waste huge amounts of energy to "mine" blocks. The committee approach has been tried with masternodes but that's also not a perfect solution because it decreases the decentralisation in the network, creating an elite of nodes that decide more than other nodes.

Lady has done her homework, thanks for all the info.

The blockchain is currently 65 GB. I don't have the disk space to use my wallet?

I would love to hear what she has to say, but I am absolutely horrible with accents - I can't even understand accents in my native language. Could we get subtitles on this video? I know my request may be hurtful, but shit, if I could fix my sound processing, I 100% would.

The more I learn about bitcoin and blockchain the less I think this will ever be able to scale to the requirements of a widely used currency.

When it comes to scaling up blockchains, solving some problems requires a change in the architecture. A tangle (or IOTA) might be an option for that. It still provides the basic features of a blockchain, but doesn't requires mining, hence enables micropayments in IoT scenarios.

How blockchain pruning impacts on the scalability concerns

It's not Charlie, it's Bob!

Seem like Blockchain is totally in a bubble right now... Their value is rated soo high, but the reality is that this technology is yet to be able replicate the conventional banking transaction rate, and there's more work to be done.... Of course there's plenty of room to improve, but lets hope Blockchain users are wise enough to spend their 'bubbling' money on R&D of Blockhain infrastructure rather than just sitting on it... the money is like an IPO, you have to quickly utilise it to create a product rather than just letting it 'rot' when investor realise their investment is just hype.

GOOD VIDEO

This was good but I miss the brown paper.

She killed that.

Some blockchains have a 15 second block time instead of 10 minutes. How does that work?

Great interview with a very intelligent woman! I could watch her talk about Blockchain all day! 😍

I don't see why using shards would be too different than purposely allowing the blockchain to fork, then implementing some method to merge those forks back together.

Thumbs up for Visual C++ 6

We need an update :-)

Interesting.

finally an interesting topic real video starts at ~11:00

Almost matching the 9th anniversary of satoshi's white paper :)

What an amazing woman. Please do more videos. 💘