Bitcoin explained from the viewpoint of inventing your own cryptocurrency.
Home page: https://www.3blue1brown.com/
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Some people have asked if this channel accepts contributions in cryptocurrency form. Indeed!
2^256 video: https://youtu.be/S9JGmA5_unY
Music by Vincent Rubinetti: https://soundcloud.com/vincerubinetti/heartbeat
Here are a few other resources I'd recommend:
Original Bitcoin paper: https://bitcoin.org/bitcoin.pdf
Block explorer: https://blockexplorer.com/
Blog post by Michael Nielsen: https://goo.gl/BW1RV3
(This is particularly good for understanding the details of what transactions look like, which is something this video did not cover)
Video by CuriousInventor: https://youtu.be/Lx9zgZCMqXE
Video by Anders Brownworth: https://youtu.be/_160oMzblY8
Ethereum white paper: https://goo.gl/XXZddT
If you want to contribute translated subtitles or to help review those that have already been made by others and need approval, you can click the gear icon in the video and go to subtitles/cc, then "add subtitles/cc". I really appreciate those who do this, as it helps make the lessons accessible to more people.
Music by Vince Rubinetti:
3blue1brown is a channel about animating math, in all senses of the word animate. And you know the drill with YouTube, if you want to stay posted on new videos, subscribe, and click the bell to receive notifications (if you're into that).
If you are new to this channel and want to see more, a good place to start is this playlist: http://3b1b.co/recommended
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I know it’s a old video now, but it would be awesome if you could explain the different algorithms and how they work or differentiate from each other like X11 (DASH) and Equihash (BTG) or Blake or what not 😁
When Alice is trying to fool Bob by producing a fraudulent block, and you state that it's possible that she finds the # that produces the specific hash, broadcasting the fraudulent block to Bob, why is there another fork? If that was the first block to be broadcast, wouldn't other miners use the hash of her fraudulent block to start creating legitimate blocks? Wouldn't that validate Alice's fraudulent block? Because every miner doesn't have their own block chain, right?
This video has to be the most comprehensive explainer video on crypto currencies. Your explanation was relatable and as lucid as it can get.
Subscribed right away.
Keep up the good work.
P.S I wish I had professors like him :)
+SAL thanks for the answer! Does this mean they need to combine the hashes of the hash root, bitcoin version number and the hash of the previous block to find the nonce? Or is this random number the only part which leads to the block hash?
It is called a nonce, which is basically the special number miners are trying to find to get that small (many leading zeroes) sha256 output. The nonce is very hard to find, but very easy to verify that it meets the criteria to get that sha output.
It should be noted that first-world governments (the EU and what's left of the US, for example) are getting wise to this and are trying to link crypto transactions to the banking system so they can tax it...and if they can tax it, that means anonymity goes bye-bye. Play safe out there, kids. If you're going to dabble in crypto, read the IRS rules so you know how to get around them.
+Star Gazer Only the identity you created to control the wallet... You can make up any name you want. Under no circumstances are you ever required to reveal your actual identity as a condition of acquiring cryptocurrency. That's my point. If you want to mess about with crypto in countries that are party to the 14 Eyes and require identification as a condition of opening a trading account, have at it. But you don't have to and, if you know what you're doing, there's no way to find out who you are. This has everything to do with HOW you engage with crypto, not the blockchain itself.
+Star Gazer Your scenario here implies that you are declaring yourself, personally, as the owner of the cryptocurrency being mined, traded, acquired, or sold in said tax haven account. You structure that shit like a trust so the LLC (or whatever you want) owns it, and then you authorize yourself in the charter (LLCs don't even require a charter) as the fiduciary. IRS couldn't touch you...unless you brought those gains onshore. And even then, there's exceptions. If you GIFT yourself, via this offshore entity, cryptocurrency, the IRS cannot tax it.
The beauty of cryptocurrency and the blockchain is that it doesn't care who you are. Someone (or something) owns the wallet/copy of the ledger, but that doesn't mean you have to personally name yourself...you just need authorization to access the funds. All the blockchain cares about is that the entity in the chain is verifiable. Also, transacting on the dark web, for instance, using Tor is virtually complete anonymity provided you do it right. You can't eavesdrop in the middle of the routing, for instance, to figure out who originated the get request.
NSA can bypass TLS and SSL, which is terrifying, but, as recently as 2015 we know they haven't been able to deanonymize Tor connections by force. If you disable trackers and plugins, enforce HTTPS, route through tor, and pay in cryptocurrency...good luck determining someone's identity.
+Data Masked What do you mean there's no way to trace purchases? Anyone can tell you every transaction every single wallet has ever made. That's how blockchain works. The only anonymous bit is when a wallet is created, you can't tie it to a particular person. But once you actually cash out money through an exchange, or through a private transaction, or you do business with anyone else, your identity can be tied back to a wallet. When the IRS learns you have an undeclared offshore account (and they will), they'll be examining your tonsils through your ass. Something you'll learn eventually is, nothing is really anonymous on the web. Youtube knows your IP, and your ISP knows who you are. And if you think things like TOR will save you, do you know who the biggest owner of TOR entry and exit nodes is? The US Government. Think about why that is for a moment.
+Star Gazer There is no way to trace purchases unless you're an idiot an use your real name....which you are legally obligated to do in places like the U.S. Hence why I said learn what the IRS (and other collection agencies) can and cannot do. It is impossible for, say, the EU or US to tax you if you start an LLC and link it to a bank in a tax haven country, for instance. That's what I'm talking about. Anyone dumb enough to use their real identity in Cryptoland probably deserves everything coming their way.
I have someone that is trying to get me to invest in Bitcoin but I’d like to know if anyone one here has ever been scammed or worse screwed by someone that invested for them? Thanks for any information.
Do not trust a particular person to invest for you! If you have done your research and feel that it is worth buying bitcoin, then it would be best to sign up at a large and we'll known bitcoin exchange such as Coinbase, Gemini, Bitstamp, kraken, and others. It is easy to make your own account.
I have someone that is trying to get me to invest in Bitcoin but I’d like to know if anyone one here has ever been scammed or worse screwed by someone that invested for them? Thanks for any information.
It is a waste of resources. Having a centralized system is way more efficient. Also if you can alter the code of the technology to fix bugs or adjust bitcoin earning rates, it is still centralized again and if you can not do this, it is inflexible.
The goal is not efficiency, but rather, it is about having a global system that doesn't rely on trusting others. Relying on centralized systems is problematic in many parts of the world. As a prime example, look at what is happening in Venezuela right now due to their centralized currency. The bitcoin code can only be improved in ways that are compatible with the older node versions. For example, trying to change the max limit on number of bitcoins would immediately be rejected by the current nodes of the network (you just end up creating an altcoin by doing so). Bitcoin is extensible enough as it is to build complex systems on top of it - such as the bitcoin lightning network.
I have a question about the example that comes along at 19:50 - is there a presupposition that most of the blockchain miners (apart from Alice) will be trying to produce legitimate blockchains? If everybody or even just most are producing garbage ledgers, won't the process hum along like it's supposed to, but with inaccurate ledgers?
It isn't much of a stretch to assume that the vast majority of miners will build on a singluar legitimate blockchain. Miners aren't the only network actors, it's possible for pretty much anyone in the world to run a full copy of the blockchain, checking every single detail down to every byte of info, including all the proof of work produced by the miners, and their not going to follow a garbage blockchain ledger. This creates an extremely robust schelling point on a global scale.
My question is: who actually checks for POW? I mean... if a malicious miner created the longest chain, each block without proof of work, and broadcast this chain to the network, would the miners automatically reject this? Or can you add a block to any chain only when you have POW?
Not only would other miners immediately reject a chain with less POW, but so would all users running nodes on their computers. All network nodes check all POW and verify all the transactions that miners include in blocks. You can do this yourself by running a full bitcoin node on your own computer.
Hey 3blue1brown! Easily the most concise intro to crypto I've seen in awhile, speaks volumes on your ability as a producer. I was hoping you could do a video on some of the issues the crypto industry is currently struggling with, such as scalability - and the limitations of classical hardware on nonce factorizations. Would be cool to explore alternative approaches
In just about 12 months, BTC has made a drop of over 80% from a peak of $19,800 to less than $4,000 and I wonder how silly those that kept talking of $100,000 and more look now. Seriously, how much more evidence do we need that cryptocurrencies are purely speculative bubbles that are best treated as such and milked at the moment? The only space for investing is in real companies doing actual business with real currency valuation. My forecast for the long-term value of bitcoin is 0$, 0€, 0£, 0¥. Don’t get me wrong, I am not a crypto hater, in fact, I am above average financially but I still have a strategy which I implement with which I make a minimum of $30,000 monthly for a couple of months already. Even though I get assistance from Mr. James Long with trade strategies and signals, I still trade on my own so I don’t have to grant anyone access to my trade account (funds). What I do is seek his opinion on the markets as he is a very seasoned analyst and trader and then I use his signals which are very simple to use in placing trades and in the process, I learn a lot from him. You can mail him** (jameslong241 @ Gmail. com) if you need his assistance too. A word of caution, never mix emotion with coins if you want to succeed and you have to be brutal as well i.e sell, buy, and trade when you have to follow the rules and always seek help if you are not already a master trader and are not making good and consistent profit on your own already.
And to add, back in the massive 2017 into 2018 BullRun, when BTC was about $19K, the expert traders were telling noob investors to HODL & BUY. All while the experience traders were slowly liquidating there BTC, XRP, ETH etc., making massive gains. Only to eventually buy back on the cheap. I asked somebody why they give these noob holders bad advice, and there response was so the NOOBS won't crash the price by panic selling, and to give the experience traders a chance for huge returns.
Amazing amazing video. Thank you so much for this, I really wanted to know the details of the mining process. This really did a good job. I still have a few questions that I hope fellow YouTubers and enthusiasts could answer. By this logic, blockchain cannot work without miners? Miners won't work without a reward, meaning for every blockchain there must be a reward system?
Correct. In Bitcoin, there are 2 sources of rewards that go to pay miners. There is the new coins that get released to the miner who finds a block (this will decrease per block over time, go read about bitcoin "halving"), and the miner also gets all the fees of every transaction they include in a block they mine (which is expected to grow to be worth more than the new coins made in each block).
When it comes to Bitcoin, block production is adjusted to 1 block every 10 minutes, and each block can only be a few megabytes large - this will ensure that the bitcoin blockchain can be maintained on regular home computers with regular home internet connections (trustless usage). However, for other blockchains that grow too big too quickly, such as Ethereum perhaps, it will be difficult to maintain the full blockchain on a regular computer, so then you might have to rely on trusting a big data center.
I'm missing something here. Not sure exactly how to word my question but I'll try to throw out some key words and maybe someone can help.
I can almost understand how this would work if it was only one large block and only one transaction happened at a time (until the miners finished).
I'm having trouble understanding two things:
How can multiple transactions happen at once and still be accounted for properly?
And what is going on with there being multiple blocks? If each block can only have ~2500 transactions, how are the blocks connected?
Edit: I think I understand that the blocks are just pieces of the larger ledger and they are the spots between the pieces the miners put in to make the blocks start with zeros. This way the ledger is still intact.
I also think that I understand that if two people make transactions at the same time, they both tell the miners and then the miners include both transactions in their next block. The order isn't super important within a block?? Maybe?
+Zack Taylor Yes, the ledger does grow over time and more bandwidth is needed for the initial download of the blockchain (when first starting up a node). It is obvious that uncontrolled growth of the ledger would be problematic, hence, the Bitcoin protocol rules stipulate that blocks can only be so large (current absolute max size per block is just under 4MB). So while initial blockchain download (over 200GB currently) for new nodes just getting synced might take a while (up to a week), keeping up with downloading (and verifying) a 1-4MB block every ten minutes is very doable on most home computers/internet connections. So it might then seem that the bottle neck for scaling is the ~2500 transactions per 10 minute interval, however, it is important to realize that bitcoin developers are now busy building out a 2nd layer protocol network ontop of the bitcoin blockchain call the Bitcoin Lightning Network, where true scale can be achieved (over >100,000 transactions per **second** is now possible).
+SAL so does the ledger get bigger over time? And take up more bandwidth as time goes on? Thanks, thinking of the blocks as pages makes a lot of sense. And I appreciate the clarification you have about multiple transactions in quick succession.
Yes, you seem to have a good understanding of how it works. I like to think of each block in the blockchain as a "page in the ledger". In general, the order isn't important within a specific block. Sometimes however a specific set of connected transactions all happen quickly before a block is mined. It is possible that A sent to B, and B sent to C, and C sent to D before a block is mined, at which point all 3 transactions will be mined together and will be listed in order within the same block (the transactions will reference each other within that one block). Each block contains a hash of the previous block. New transactions need to reference past transaction outputs (from previous blocks) that were unspent until now.
How to contribute or make a donation for you to keep on making such a great comprehensive videos? Can you go into the details of how the sk and pk are related and how it is possible to verify the signature and the message by knowing the pk? Or any references on this topic? Thanks!
You are confusing the market for bitcoin and the actual bitcoin system. There was such a thing as the "internet bubble" some years ago, but that doesn't explain how the internet works. Also, people don't use graphics card to mine bitcoin (you need an ASIC machine).
+Ivan Novotný All nodes already have all the account balances with associated public ADDRESSES (and addresses can only be derived from an associated public key which must be derived from the private key). So whenever a sender makes a transaction, it is digitally signed with their private key and it will show the public key and show and that it **matches to that specific public address**. So no, an attacker can't alter the transaction without the correct private key - it would be invalid as it won't "match" the public address. The transaction effectively states to the network "this X amount of bitcoin now belongs to this NEW address", and there is no way for an attacker to change it (unless of course they somehow manage to steal your private key and make a transaction before you do). I hope I was able to explain that well enough.
+SAL SAL Ok. But, for veryfiyng the nodes must have the public key of my signature. What happends when somebody change this public key as it will passes to the attacker's private key? I'm sorry for explaining my question so unluckily. I'm talking about man-in-the-middle attack. Attacker doesn't need to know my private key for signing but he can still attack my transaction by changing the look of my signature's public key before entering the broadcast to all nodes. What it will mean? Because when he changes it, the network verifies the trandaction as valid. Or not? Couldn't he change also the transaction content? Or modifying the public key of signature before entering the network is pretty impossible?
Once the sender digitally signs the transaction, that transaction message gets broadcast to the entire network, each node verifying it is correctly signed. If nodes see that it isn't a valid signature, then they don't propagate it. If it is a valid signature, it will then be added to the immutable blockchain by a miner.
What if Alice exchanges the money for another currency in the meanwhile, this system is neat but also flawed. With time its going to become unmanageable with never-ending history. Not to mention all the power needed to keep it running.
I struggled to grasp this concept till I learn the below on a Cryptocurrency 101: Transaction records are collected in blocks. As transactions transfer ownership of CryptoCurrency balances, each block represents an update of the user’s balances on the network.
Blockchain technology underpins the global transactions of CryptoCurrencies ensuring transparency, enhancing security through a secure record-keeping system. It also allows for improved traceability of data and transactions across the different types of CryptoCurrencies, along with increased efficiency, speed and a reduction of costs compared to that of traditional banking systems.
Described as the ultimate smart currency, CryptoCurrencies represent a digital currency which is encrypted. It offers users a verifiable transfer of funds operating independently of a central bank across global networks.
The system keeps an overview of CryptoCurrency units and their ownership and also defines whether new CryptoCurrency units can be created. When new CryptoCurrency units are minted, all network participants are notified as the ledger is decentralized and is automatically updated. if its helps you as well there is another on Bitcoin 101 and blockchain 101 which may help. https://www.cryptofish.com/blog/what-are-cryptocurrencies-and-how-do-they-work/
It depends. It will initially just sit there "unconfirmed" until it gets mined into the blockchain. Usually no miner will do this for free, so yea, eventually it will just get dropped and doesn't go through. However, if the recipient of that zero fee transaction is serious about wanting that transaction, the recipient can pick up that zero fee transaction and use it in a subsequent transaction (to themselves) that does have a fee (the fee for the subsequent transaction will cover the 2 transactions). This is known as a "child pays for parent (CPFP)" transaction.
The transaction was digitally signed with Alice's private key, and only Alice's key can sign the transaction she sends. If Bob tries to make a change, it wouldn't be valid - it will simply be ignored by the network.
This video is really an awesome explanation! I have been reading up on Bitcoin along with other Cryptocurrencies and Blockchain to try and get a better understand and I would definitely recommend this video which I will definitely be sharing. Along with this I also found the below really helpful in terms of understanding Bitcoin and Blockchain. https://www.cryptofish.com/blog/bitcoin-101/
Why is the proof of work necessary at all? If we already need, for every transaction, a signature that only the person making the transaction can produce, then how could anyone send fake signals? They'd need a signature they can't possibly fake...
The problem becomes that the person sending the transaction can still produce ANOTHER valid signature to "double-spend" their money (a conflicting transaction). Proof of work solves this double spend problem WITHOUT a trusted central entity.
If you want to do so without trusting any third party, then the answer is yes. Maintaining a fully synced up copy of the entire blockchain is known as running a full node. Your node can tally up the bitcoins of your addresses to show your balance. This is actually the key feature that makes bitcoin unique compared to all other previous forms of money - you can easily do full validation of the entire system yourself without relying on any third party!
Unfortunately, most people are lazy and do choose to rely on other services to tell them their balance. Even worse off are people who store their coins with trusted central entities, which make them a big target for hackers.
21:25 doesn't this mean that bitcoin is completely infeasible to be used on a daily basis? For example if I go to the shop and pay for something with bitcoin, the shop will have to wait for quite a few blocks to be added before they can trust that they've been paid. That would take on the order of at least minutes, which is far too long.
Not only that, but fees for blockchain transactions can be expensive for everyday small payments. So while the bitcoin blockchain is being optimized for security and decentralization, there is a second layer payment network being developed called the "bitcoin lightning network" where payments are now instant and fees are extremely small (on the order of 1/100,000,000 of a bitcoin).
+VwertIX Nope, but it's well-established in the English language to use male pronouns for anonymous mechanistic entities so deliberately overriding this with a female pronoun grates annoyingly to the average casual listener (woke bell-ends excluded). If the author wants to get laid there are easier ways than inserting female pronouns where they're not required and statistically highly unlikely to be correct.
+JOe-HOs there is no way to see the number of individual miners, however, we do know roughly how much total mining power there is. Many miners team up together into mining pools - just googling "bitcoin mining pools" should show the big pools out there.
Then transactions would stop getting included in the blockchain. But it would also mean it tons of profit being left up for grabs, which would lead to many people (my self included) to jump into the mining game to get some easy money, and thus mining would resume.
13,500,000 GRAM Plan to sell.
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