> How does consensus work in an enterprise blockchain?
It doesn't, because blockchain doesn't solve consensus problem.
It doesn't, because blockchain doesn't solve consensus problem.
But then, consensus problem is a problem of establishing a specific value for almost all participants. Which implies that the value is established, which means that the protocol terminates. Blockchain was not designed to ever terminate, so it's not a consensus protocol even if for no other reason.
Otherwise, what parts of blockchain exactly establish a common value among participants and what exactly is this common value?
In smaller chains, there can certainly be consensus, it just won't be as trusted as a public chain and 51% attacks are potentially more feasible due to it having a smaller economic barrier.
It's a name used for Bitcoin's protocol. It doesn't mean it's consensus.
How does the established value by this "consensus" protocol look like? And why do you consider it established, when other participants can have a totally different view of the list of documents in the protocol, or your view can change completely with next message? How is it an agreed value? And at what point should we look at the views of two different participants to see the same value?
And how does it relate to Lamport's original publication about the consensus problem?
That's the point, one should not have to consider the values of other nodes to reach consensus. If the network agrees on something, that's consensus. If a certain node doesn't, that's their problem.
It's agreed because that miner solved the block problem first. If you have a different view, you must fix it. This is how it achieves consensus.
Not sure what specific consensus problem Nakamoto consensus doesn't solve, but it does provide a consensus based on the specific rules of the network. So yes, it's a consensus system. You might want to be contrarian and dispute what consensus means to you. But that's what it means to to the miners and that's what matters.
Which of them? Because every node has a slightly different view and doesn't know how it differs from anybody else's view.
> That's the point, one should not have to consider the values of other nodes to reach consensus. If the network agrees on something, that's consensus. If a certain node doesn't, that's their problem.
The problem is that every node has slightly different view. You can't tell "this is the agreed value", because no particular node has this value as its state. Yet somehow it emerges as network's agreed value? By what means (algorithm) anybody can take a list of transactions and say "this is the network's agreed value"?
Not to mention that the list of transactions constantly changes, you didn't address the problem that agreed value requires the protocol to terminate first.
> It's agreed because that miner solved the block problem first. If you have a different view, you must fix it. This is how it achieves consensus.
In what way is "solve block problem" consensus?
> Not sure what specific consensus problem Nakamoto consensus doesn't solve,
Yes, this is typical problem with blockchain enthusiasts. They're usually too uneducated and don't know the fundamentals, like the definition of consensus problem. I pointed you to Byzantine generals paper already, it should have been easy to find even with just "consensus problem Lamport" keywords.
Nakamoto consensus solves the Byzantine problem quite well. The list of transactions doesn't not constantly change? Are you saying there is no consensus as to the value of the first blocks?
I get that it's cool to be contrarian and it makes people feel smart to badmouth blockchain. But Nakamoto consensus does reach a consensus on value that is accepted by the network.
It's like saying a voting election didn't matter because certain people didn't participate.
You do realize that this "my contrarian view" is what computer science calls "the consensus problem", right? And that "my contrarian view" comes from a highly regarded publication that's thirty years old?
> Nakamoto consensus solves the Byzantine problem quite well.
Explain to me how. Byzantine generals problem comes with a rigorous proof that network cannot agree on a single value if the cooperating nodes don't outnumber the adversarial ones by more than 2:1. The blockchain guarantees its functions with merely 50% + 1 of cooperating nodes. Something doesn't add up if blockchain was intended to solve consensus problem.
> I get that it's cool to be contrarian and it makes people feel smart to badmouth blockchain.
Oh, but I don't badmouth blockchain. I think it's quite ingenious cryptosystem. I only badmouth blockchain enthusiasts, and the undereducated ones at that.
Blockchain was never intended to be a consensus protocol, it was always a timestamping protocol. We had a number of those before, but blockchain is the first one that doesn't use trusted third party. This is the ingenuity of blockchain, not consensus that blockchain doesn't solve.
And then the idea behing Bitcoin, that a digital cash protocol (of which we had some number before, too) can be built on top of published and timestamped transactions, which together form a ledger. This is smart as well. But it's still not a consensus protocol.
> But Nakamoto consensus does reach a consensus on value that is accepted by the network.
Despite that nobody can tell what value exactly was agreed upon? And despite that you can't designate any specific point in time that the agreement is reached? I fail to see how is this "consensus".
True there are other types of consensus that are perhaps 'fairer' but that's not the issue here.
So yes, it is a consensus protocol. It's called Nakamoto consensus, and it's perfectly fine for its purpose.
It's amazing how many things you got wrong in such a short statement. First, a program can't say when this "eventually" is. Then the "agree" part is wrong, too, because it can change just like that (because of forks), which even changes the history, not just a single transaction or group of them. And then there's also "all miners" part, which even read as customary universal quantifier ("all" meaning "most of them") falls apart if you remember that this needs to be assessed by a program with limited knowledge.
It's not a consensus in any computer related meaning that one could think of.
Because "it might fork" that's why it's not a consensus? lol, ok buddy.
In this case consensus isn’t really necessary because all participants are trusted and should rarely differ (since they all have the same boss at some level).