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How Blockchain Works
- mathnmusic 8y agoI used this blockchain demo to teach a class this weekend. Many thanks to Anders Brownworth for creating this: https://anders.com/blockchain/blockchain.html https://anders.com/blockchain/blockchain.html
- s_dev 8y agoEven the MIT URL in the source uses Anders demo -- it's that good. Edit: Oh wow -- Anders is the author of the MIT demo. All the same stuff really.
- scottmsul 8y agoA cool idea would be to split the class into groups where they pass around a piece of paper and can add their group's block and pass to the next group.
- nchuhoai 8y agoI created the following interactive tutorial: https://blockchain.nambrot.com/ https://blockchain.nambrot.com/ Would love your feedback on it!
- olalonde 8y ago<rant> This ship seems to have sailed already but I feel like it really should have been "How blockchains work". We don't say "How relational database works", "How operating system works", "How computer works", etc. We do say "How Linux works" or "How Bitcoin's blockchain works".
- blowski 8y agoJust to play devils advocate here, I drink “milk” not “milks” despite the fact that it might be from soya, cow or goat.
- stolenmerch 8y agoBecause 'milk' is an unmarked plural. 'Chain' is not.
- debacle 8y agoMore importantly, why aren't people talking more about blockmilk technology?
- joshgel 8y agoThere aren't enough edible cereals compatible with blockmilk for mainstream adoption yet.
- deleted 8y ago[deleted]
- zepto 8y agoBlockchain is an unmarked plural
- hannasanarion 8y agoNo it isn't. Nobody says "one blockchain, two blockchain, oh hey look I found a bunch of new blockchain". Blockchain is here being used in reference to the technology itself, not the collection of its manifestations. Just like you might say "how the internal combustion engine works" or "how insertion sort works"
- supersock 8y agoDoes anyone say "here's one water, two waters"?
- chaosphere2112 8y agoWhen ordering at a restaurant, yes.
- theoh 8y agoForbes published an article containing this line "To understand its functioning and functionality, it is necessary to start first with the definition of blockchain." It's annoying in the same way that people in marketing using the word "digital" as a noun is annoying. But it's how financial/business people are typically abbreviating "blockchain technology". It's like Brexit: there are many possible implementations, but one concept.
- shuntress 8y agoI understand why people do this but it also annoys me. It's just a short-handed title given to a concept by people who need to talk about it but don't fully understand it. Like the way politicians talk about "cyber" Edit: The use of "blockchain" in this article rather than "a blockchain" or "blockchains" seems to be just to conform to the broader discussion. The linked page does seem to demonstrate a clear understanding of how blockchains work.
- will_brown 8y ago>"How Bitcoin's blockchain works" Blockchain is both the descriptive label for distributed ledgers and the pronoun for Bitcoin’s Blockchain. It could have been “how blockchains work” if talking about blockchains generally but “how Blockchain works” would seem to be the title of an article discussing how Bitcoin’s Blockchain works specifically.
- aklemm 8y agoIt's like Apple welcoming me to "iPhone"...it should be "your iPhone" or "this iPhone" or "an iPhone". iPhone is not a state of being.
- Moodles 8y agoNow explain to a technical audience why some people say nonsense like how it’s the next internet or how it’ll change the world please.
- easymodex 8y agoWell it has great potential to remove a lot of beaurocracy related stuff. It's not really the next internet but it can very easily change the world if it's properly implemented. But if you're talking specifically about cryptocurrencies and bitcoin then I assume you're a bit salty because you think you missed the hype. Don't worry tho, we are still early adopters.
- Moodles 8y agoI actually conjecture that blockchains are only useful for cryptocurrencies like bitcoin. It's when you see companies using them for tracking their supply chain, their music, their photos, their porn, their bananas in Laos, their weed, that I roll my eyes into the back of my skull. There's no way it has any potential to simplify any beaurcracy, unless you think introducing multiple nodes on a network and constantly making them talk to agree on their own databases is simple. People always compare blockchain in banks to banks using pen and paper. Why not just banks using computers?
- yarrel 8y agoTrust. If you are a small producer and you send a shipment of your widgets to Wal Mart, and Wal Mart then say "what widgets?", the efficiency of their SQL Server installation isn't a benefit that will bring you much comfort. If you are a small producer and you send a shipment of your widgets to Wal Mart with little rfid stickers on tracked by a blockchain system that you, the shipping company, border security, Wal Mart's warehouse and Wal Mart's stores run nodes for, you have a system that may bring you a bit more comfort. Running a node is simpler (or at least more efficient - pen and paper is simpler than SQL Server...), and the outcomes more encouraging for all participants, than some of the alternatives. The question "Why not just banks using computers?" is where distributed timestamp servers came in and there is an extensive literature devoted to both the ideological and practical arguments around this. Briefly because banks are untrustworthy, expensive and slow. Banks themselves using blockchains is recuperation ideologically speaking, and FOMO technologically speaking. It is less silly to the degree that it does improve banking transparency and trustworthiness, but abandoning proof-of-of-work for the nonsense of "permissioned" blockchains restores it to being very silly.
- geraldbauer 8y agoA great way to learn about blockchains is building your own from scratch / zero in Python, Ruby, JavaScript, etc. Find many starter samples and articles in the Awesome Blockchains [1] collection. [1]: https://github.com/openblockchains/awesome-blockchains https://github.com/openblockchains/awesome-blockchains
- brighton36 8y agoYou know, I used think the technicals mattered. Then I realized how the technology behind the technology behind bitcoin works: https://twitter.com/mikeinspace/status/1043577578357952512 https://twitter.com/mikeinspace/status/1043577578357952512
- p4bl0 8y agoThis is a very good and clear explanation of how bitcoin type blockchains work. It could easily have been made simpler and more general at the same time by omitting the proof of work aspect, which is not even discussed actually. The "begin with four zeros" rule is completely arbitrary, it could be any prefix of any length depending on the necessary amount of work that you want, including zero. And with an empty prefix we still have a blockchain with all the properties presented here that hold.
- abraham_lincoln 8y agoIs it necessary to be based on the prefix, or can it be implemented by pattern, for instance, every even byte is zero, or the 4 bytes after the first 3 bytes must be all 7s, etc? Is it simply brute-forcing hashes, looking for matching patterns that are not yet known?
- dlubarov 8y agoIn practice Bitcoin treats SHA-256 outputs as integers, and requires them to be under a certain limit, based on the current difficulty. That way we can make small adjustments to the difficulty. If we actually used a rule like "this many zeros in hex", the difficulty bumps would have to be rather large.
- lmpostor 8y agoI don't see what prevents you from adding complexity. And yeah, but it also requires valid transactions if you want to collect fees, as well as the knowledge of the valid previous block.
- thallukrish 8y agoAfter a long time of procrastinating understanding block chains, I could watch the whole video and understand it finally. Thanks for the great visual explanation.
- dsco 8y agoFor the Javascript lovers out there, I wrote a client-side project which conceptually demonstrates how a blockchain works. It runs in your browser and uses web workers to concurrently mine blocks, showing how miners, transactions and addresses fit together. https://github.com/sunmer/lightchain https://github.com/sunmer/lightchain
- thedancollins 8y agoOver the past year I have gone from Blockchain enthusiast to more blockchain gadfly. The concept is truly revolutionary but the use cases I typically see trotted out are not compelling in any significant sense and could be solved without blockchain. I believe the reason for this is due to the fact that the true value of a blockchain solution is not in the data aspect of it (which everyone gravitates to and can quickly grasp and understand) but more in the transactability that a blockchain solution can offer. And the value of radical transactability requires much less of a myopic understanding of a person's business vertical than many professionals possess. In energy for instance, much talk about the financial aspect of a blockchain-based energy solution but absolutely zero talk of how the physical grid and infrastructure would engage to support the financial activity.
- prostoalex 8y ago> The concept is truly revolutionary In what way? Publishing a DB dump with a checksum has been around for decades, and doesn't require a new user to download an entire history of deltas from day 1.
- thedancollins 8y agoBecause it finally provides a mechanism by which bad actors on a network could face repercussions for their activity. Consider how different the internet would be if hyperlinks were two-way rather than one-way. Again, it is not only about data, it is about the speed of transactability that would result when value could be exchanged instantaneously with radical transparency behind the actors on the chain. Bankers go away, auditors go away, credit requirements for market participation go away. What could be do with the trillions of dollars tied up and sitting in credit collateral accounts? Liquidity is a good thing.
- prostoalex 8y ago> it is about the speed of transactability As somebody pointed out https://news.ycombinator.com/item?id=18076542 https://news.ycombinator.com/item?id=18076542 high transaction throughput is not exactly the killer feature of modern-day blockchains.
- Isamu 8y agoQuestion: the video explains that you can't just change a bit in the middle of the blockchain without having to fix all the subsequent blocks, making tampering labor intensive, but not impossible. Is it supposed to be VERY labor intensive, depending on the length of the chain? Then ultimately a chain that is consistent might have been manipulated, but you can check it against other copies. At this point you could be just comparing plain text ledgers (but blockchain comparison could be easier by just comparing hashes.)
- kybernetikos 8y agoThe reason it's VERY labor intensive is because in a PoW blockchain, each block also includes a value that combined with the previous blocks hash hashes to a number less than the difficulty (the value labelled nonce in this demo). The difficulty can be adjusted to ensure that finding such a number is very hard. Obviously in the demo, it was not so very difficult - your machine was able to work out a value for the nonce very quickly by itself, but in the real network, the difficult is set so that this is hard. So hard that the whole network of miners working together will only find one, on average every x minutes (configurable depending on how you update the difficulty). This means that creating another block is difficult. The whole network has the rule that longer chains of blocks are preferred over shorter ones, so as more blocks are added to a chain, the amount of computation required to overtake the main chain and have your modified chain accepted as the truth becomes very large. To rewrite history, you don't just need to modify the data and recalculate the hash for each subsequent block, you need to find a nonce that works for each of the subsequent blocks, and you need to be doing this faster than the main chain is adding new blocks, or your chain will never be as long as the main chain, and it will never be considered the 'truth'. That's why people talk about 51% attacks - the idea is that you need to have a majority of the hash power of the network working on your dodgy chain if you want it to overtake the main chain. Now there are things you can do with less than 51% of the network hash power, but for the naive approach, you're going to need a phenomenal amount of computing power to stand a chance of having people accept your version of history. For alt-coin chains with very few participants, there have been real attacks along these lines. It's hard to imagine attacks like this succeeding against any of the main blockchains though. And yes, comparing two blockchains for equality is very easy - the hash of a block includes the hash of the previous block, as you can see in the demo, so the hash represents the entire history. If two blockchains have a different hash for the top block, they have different histories.
- jondubois 8y agoI remember that a lot of people were saying that cryptocurrency is not revolutionary but that blockchain is. I think the opposite is true. Cryptocurrency is revolutionary and blockchain is just one of several known technologies that make it possible. Cryptocurrency is the most important use case for blockchain tech. What I like most about cryptocurrency is the fact that it financially incentivizes massive collaborative behaviour without requiring participants to actually own any capital at the beginning. It lets you create financial incentives out of nothing. Before cryptocurrency, this kind of collaborative game-rigging behaviour was only accessible to people who owned a lot of capital (e.g. 'activist' investors). For example, I could launch my own cryptocurrency tomorrow and then use it to air-drop (aka bribe) journalists to write about my project in a positive way - This is pretty standard behaviour among Silicon Valley startups but now you can do it without VC money. It sounds bad but it's much better than what we have now. It levels the playing field for everyone. For the first time ever, regular people have the power to change the world together through incentivised collaboration.
- aklemm 8y agoBut if those cryptocurrencies keep never amounting to anything, then the bribing won't keep working, right?
- jondubois 8y agoIt will but maybe it will be harder to do it. It's like if you could give some shares of your startup to a journalist in exchange for writing an article about your startup. Cryptocurrency can act like shares without central authority. If enough software services rely on a specific cryptocurrency as payment, then it has actual intrinsic value
- aklemm 8y ago"If enough software services rely on a specific cryptocurrency as payment, then it has actual intrinsic value" I wish I'd seen this earlier. Pretty sure this is false, but it is an excellent summation of the thought behind what's run up digital currencies.
- Razengan 8y agoI have yet to watch/read the link, or catch up on the hype, but why is "Blockchain" referred to in the singular? As in "the blockchain" or just "blockchain" (often capitalized.) Is there only one of its kind? Is "How Internet Works" grammatically correct? EDIT: I didn't see this was already asked in another comment.
- fartcannon 8y agoI too want to know this. You'd think it would be "How (a) blockchain works" or "How blockchains work"... The way this is written feels like they're suggesting there is only one.
- beefman 8y agoOriginal site: https://anders.com/blockchain/ https://anders.com/blockchain/
- tim333 8y agoAnd original discussion from back when ETH was $11 or so a year and a half ago https://news.ycombinator.com/item?id=13566951 https://news.ycombinator.com/item?id=13566951
- WC3w6pXxgGd 8y agoThis is the best explanation of blockchain I've found.
- abraham_lincoln 8y agoWhy is it assumed a blockchain is always distributed? I think that distinction needs to be made (centralized vs distributed).
- aklemm 8y agoIs there any interesting work going on with blockchain for identity management (Internet or other, I guess)?