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  • So over the past year the Bitcoin network has reached his maximum

  • Capacity all the blocks are becoming full and as a result there's been a lot of debate about how we can scale

  • Bitcoin in the future

  • So i'm gonna talk a little bit about some of those proposals, and what they could mean and what's the trade-offs?

  • Some of the technical solutions being proposed to improve the scalability of Bitcoin are so that it can handle more and more users

  • because if Bitcoin was to become mainstream then it needs a lot more scalability that it has right now and

  • The problem is that when Bitcoin was first created the founder of Bitcoin who originally published the code

  • About a year after he published a code. He inserted a block size limit well

  • What's called a block size limit in the code which means that each block has a maximum block size of one megabyte

  • So to give a quick recap of how the Bitcoin network works

  • The Bitcoin network is a decentralized system

  • where anyone can run their own node and these nodes will have a copy of what's called the blockchain and

  • The blockchain is essentially a series of blocks

  • That contain all the transactions in the system this creator of Bitcoin realized that there's a potential problem here of

  • What's called a denial of service attack

  • someone could potentially spam the network with transactions and make blocks that are very big and

  • so he

  • Created a limit that each block should be no bigger than one megabyte and this limit is hard-coded in all of the

  • Software that you use to run a Bitcoin client or node on your own computer so that means

  • your software will automatically reject any block that is bigger than one megabyte and

  • Now we've reached a point. Where blocks are becoming full

  • They've reached a maximum capacity of one megabyte and so no new transactions can be put in in the blocks so

  • That gives us a capacity of around three to seven transactions per second which isn't very much

  • Because there is now more demand for more transactions per second in the network as a network has grown

  • Is it a simple case of if we were able to make these blocks bigger you could fit more transactions in?

  • Sure, yes, you can do that if you make the blocks bigger

  • It's a naive and very simple way of increasing scalability, but the main

  • Argument against it from its critics has been that

  • if you increase the block size

  • Then the block chain itself would get bigger and that means

  • Every single person who runs a Bitcoin node on their computers,

  • What's called a full node,

  • Has to have all the data of the above the whole blockchain in order to verify the whole blockchain correctly

  • If we increase the block size

  • you would need more and more storage to store a copy of the blockchain and this is a problem because

  • The all point of Bitcoin is that as a decentralized system

  • Anyone should be able to run their own node when this limit was first added in 2009 2010

  • The Bitcoin wasn't as popular so it was much easier to modify the code and insert

  • new changes and

  • uncontroversial, or you know

  • Protocol rules like that. Now, It's a much bigger space so now each change needs a lot more

  • Consensus if you'd like because if you were to if you wanted to increase the block size this would create what's called a hard fork

  • You would essentially create a blockchain that's incompatible with all the existing nodes that run on the Bitcoin network

  • Because the existing nodes, they will reject any block that is bigger than one megabyte and everyone will have to upgrade all the

  • Software so this is the kind of change that requires every single person to agree to it or the majority of the ecosystem

  • To agree to it. People who want, who are thinking about how to scale

  • Bitcoin kind of really fit into two camps

  • Camps of the people who are advocates of what's called on chained scaling and people who are advocates of what's called off chain scaling

  • The idea of on chained scaling is that we want to increase the capacity of the Bitcoin network

  • by increasing the number of transactions that we actually put in the blockchain itself and

  • you and you would do that by increasing the block size and

  • Yes, that would make it more expensive to run a Bitcoin full node

  • but argument is that the majority of Bitcoin user they'll run Bitcoin anyway if you have a Bitcoin wallet on your

  • On your phone, or if you use a web wallet

  • It's not a proper Bitcoin node if your wallet

  • Trusts a different node or some centralized service to some extent

  • to get information about the Bitcoin network and get information out of blockchain so

  • one of the original things that the original creator of Bitcoin said is

  • that he expects that as the blockchain grows in size and

  • Ultimately people will no longer be able to run nodes and nodes will become super nodes

  • you will have to have access to data center to run nodes, and that was kind of part of the plan

  • But one of the things that the creator of Bitcoin anticipated was that Moore's Law

  • would catch up with the blockchain size

  • So that's regardless. It wasn't mega expensive for someone to store a copy of blockchain. But unfortunately Moore's law

  • hasn't, has been somewhat dead for the past few years. Hard drive storage

  • Has largely remained at roughly the same cost for the past few years

  • It's kind of stopped, and that's kind of created a problem

  • So that's what on chained scaling is about.The idea of off chain scaling is that let's move the transactions out of the blockchain

  • Do we really do we really need to put every small

  • Transaction like if you go to a coffee shop and buy coffee

  • Do we really need to put it on the blockchain and do we really want

  • Every single person who runs a Bitcoin node to have a copy of that little transaction

  • so the idea of off chain scaling is let's only put big or

  • important transactions on the blockchain and let's put all of those micro transactions off the blockchain and

  • One of Percival's for doing that is a system called the Lightning Network and the Lightning network is basically

  • using something called payment channels between different individuals

  • to facilitate off chain payments for example Alice might send Bob ten dollars

  • And then Bob sends at least five dollars in the next day

  • So what they do is instead of having every single payment on the blockchain?

  • They just keep a balance sheet between them and they put all the payments on their balance sheet and then for example after a month

  • They say let's see what is the final balance and let's set all that balance on the blockchain

  • So you only need to put that final payment on blockchain rather than every single payment in between

  • and

  • You can extend this at least as a payment channel with Bob and Bob has a payment channel with Charlie and let's suppose Alice wants

  • To pay Charlie Alice kind of route that payment through Bob, which would then send a payment charlie

  • And this is the idea of lightning network, you use a route or a network of payment channels

  • And you would find the route

  • between person-to-person that you can make that payment of the blockchain and

  • In theory it sounds like a really great idea, but there are some

  • controversies around it so

  • some people don't think that it would be very feasible if

  • This would be able to be used by millions of users, for every single person to find a route between

  • any other person in a decentralized way because one of the

  • Things with that network is that

  • In order to establish a payment channel you have to deposit a

  • certain amount of money, which is at least a minimum amount of money of how much you expect to

  • go through that payment channel and

  • That some people just don't have the upfront capital so people expect

  • What's called large payment hubs to facilitate that so you would have a large payment hub

  • That has a large amount of deposit inside of it, and yo you would route your payments to that so in some way

  • There's a bit of centralization involved with that if you have on chain scaling we have super nodes

  • But if you have off chain scaling we might have large centralized payment hubs

  • So it is still bit of centralization involved in both

  • Bitcoin cash when Bitcoin cash forks off from Bitcoin the value of Bitcoin cash on the first day was something like 500 dollars

  • So people were 500 dollars per coin for free out of thin air when this fork happened

  • So it's possible that some people but the value of Bitcoin has risen

So over the past year the Bitcoin network has reached his maximum

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ビットコイン、ブロックチェーンフォーク&ライトニング - コンピュータマニア (Bitcoin, Blockchain Forks & Lightning - Computerphile)

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    林宜悉 に公開 2021 年 01 月 14 日
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