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How Blockchain Works

blockchain.mit.edu

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Re: How Blockchain Works

#101

Post by thedancollins »

the_snooze wrote: post #93
w1nt3rmu4e wrote: post #89

Earlier quoted context omitted.

Honestly, I don't see why everyone hates blockchain these days. Two things are going on: 1. It's a potentially revolutionary technology (trust-less, decentralized, nearly tamper proof, etc) that hasn't yet found a killer app(s) at scale 2. We're in the middle of a gold rush with zillions of shit-coins really throwing off the signal to noise ratio This period will pass. Blockchain tech is maturing (PoS replacing PoW,…

>It's a potentially revolutionary technology (trust-less, decentralized, nearly tamper proof, etc) that hasn't yet found a killer app(s) at scale I'd argue it has: cryptocurrency and all the criminal enterprises it supports (e.g., ransomware). If you're willing to enter legally-enforceable contracts with other parties, then "trustless" and "decentralized" don't matter all that much to you.

Ok, but counterpoint is obvious. Are there people using blockchain for illicit purposes? Yes. And also water is wet. There are also many people using cash for illicit purposes.

And of course, you can always include as many people in your transactions as possible but what blockchain does is to make those people unnecessary. Why is this important? Because it enables micro-transactions and credit-less agreements. A blockchain provide options that fiat-based systems can never provide.

Re: How Blockchain Works

#102

Post by romaniv »

prostoalex wrote: post #65
thedancollins wrote: post #33

Over 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 quickl…

> 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.

I'm curious about this as well. No one seem to be talking about specific attacks mitigated by blockchains as opposed to authorities signing current state.

The definition implies that if someone says "I'm on block 1000" they cannot create altered version of history without touching all the blocks after the change.

But how is this useful? If there is a disagreement about the last block, majority wins, right? So couldn't majority simply have the most up-to-date version of the database with a single signature?

Re: How Blockchain Works

#104

Post by thedancollins »

w1nt3rmu4e wrote: post #89
thedancollins wrote: post #33

Over 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 quickl…

Honestly, I don't see why everyone hates blockchain these days. Two things are going on: 1. It's a potentially revolutionary technology (trust-less, decentralized, nearly tamper proof, etc) that hasn't yet found a killer app(s) at scale 2. We're in the middle of a gold rush with zillions of shit-coins really throwing off the signal to noise ratio This period will pass. Blockchain tech is maturing (PoS replacing PoW,…

I like the Bangkok example because it highlights that one of the problems we have in the "more developed" world economies is that we have existing systems and financial institutions to hurdle. Developing economies do not and it is giving them a fast track tot he new way of doing business. There is a good chance that when blockchain takes off - it will catch Wall Street off-guard.

Re: How Blockchain Works

#105

Post by vec »

neospice wrote: post #96
vec wrote: post #87

Earlier quoted context omitted.

Nope. The whole point of proof of work is that it informs clients which version to consider authoritative in the case of a conflict. If my tampered copy has higher proof of work than the peer with the correct version then, by definition, mine is correct and the other peer's is outdated. Correctly implemented peers will recognize this and overwrite their local cache with mine, and even if they don't other peers will a…

How is "higher proof of work" defined in this context? Also, doesn't consensus of the majority of peers have any bearing on which is more authoritative? I.e. if all nodes except for your malicious node report a single chain, why would yours not be rejected?

"Proof of work" means the total number of hashing functions, from the point of divergence forward, used in signing the blocks.

Consensus doesn't work like you're implying. If it did, I could spin up a peer on N+1 AWS servers, where N is the current number of peers on the network, and now my version has the majority of peers supporting it.

The whole idea behind proof of work is that it's impossible to fake. The version that took the most net computing power to generate is by definition authoritative. This means that the only way to make a malicious version of a chain is to actually, genuinely do more total work than the legitimate actors collectively did. The other side of this coin, though, is that it explicitly allows me to generate a malicious version of the chain by actually, genuinely doing more total work than the legitimate actors collectively did.

Re: How Blockchain Works

#106

Post by abraham_lincoln »

p4bl0 wrote: post #69

This 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 prefi…

Is 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?

Re: How Blockchain Works

#107

Post by thedancollins »

poulsbohemian wrote: post #83
thedancollins wrote: post #33

Over 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 quickl…

Can you give an example of this transactability, especially in an example where it would be superior to existing solutions? Also, are you the Dan Collins in Phoenix? I think we did a project together about 4 years ago...

I am not that Dan Collins. And as for an example - credit card transactions. I am sure somebody else can provide more color but it is my understanding that there are 6 or 7 intermediaries that each credit card transaction travels through - each taking their fraction of a penny and delivering questionable value - all to eventually have that transaction finally settle 2-3 DAYS later. On a blockchain that can happen in as little as 10 minutes and nobody else is involved (other than the miners in the case of a PoW consensus-backed blockchain like Bitcoin).

But more importantly, blockchain might provide a way to get around the information asymmetry problem that dominates financial value exchange. Blockchain is better in the idea that the entity trying to transact exposes all their cards on the blockchain - if they want to extract value from a transaction it will not simply be because they "know more than you". Power to the people.

Re: How Blockchain Works

#108

Post by abraham_lincoln »

Moodles wrote: post #20
gibsons77 wrote: post #17

Earlier quoted context omitted.

Well.. It will change some aspects of our world. Particularly financial assets at first, but increasingly it will play a role in any peer to peer exchange requiring trust. Simple past examples are systems like OpenPGP that bind public keys to owners. Programmable blockchains allow generalized applications requiring decentralized trust. A good example of a use of blockchain outside of financial assets is in trust mana…

I have a PhD in cryptography. Please be precise. Exactly what problem will blockchain solve for vehicles? You can't just hand wave and say stuff like "decentralized trust management" and expect us to nod along.

Service records for the life of the car.

Vehicle purchasing/financing paperwork.

Inspection tracking.

Re: How Blockchain Works

#109

Post by decentralised »

prostoalex wrote: post #65
thedancollins wrote: post #33

Over 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 quickl…

> 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.

Technically, you don't need to download the network's history to interact with it.

The reasons to run a personal node are related with privacy, trust and decentralisation.

Re: How Blockchain Works

#110

Post by romaniv »

thedancollins wrote: post #73
prostoalex wrote: post #65

Earlier quoted context omitted.

> 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.

Because 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 a…

>Because it finally provides a mechanism by which bad actors on a network could face repercussions for their activity.

Would this require globally broadcasting all transaction? If yes, wouldn't globally broadcasting all transaction give you a lot of transparency anyway?

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