[__MatrixMan__]

So it stops being a blockchain if the criteria for adding a block is based on something else? Or do you intend to update your definition to incorporate other consensus mechanisms as they emerge?

Seems to me that a more useful definition would abstract out the consensus model such that a blockchain is essentially a merkle-linked-list together with some function for determining which of two candidate next-blocks will be the actual one, but without getting too specific for what that function is... just because there's so much potential for variation there.

[jazzyjackson]

> just because there's so much potential for variation there.

There really isn't. Either you expend some resource to make it expensive to attack or you stake some resource so you have something to lose to prove you're not a bad actor. I've never seen anything more creative than this.

[__MatrixMan__]

Or you participate in some activity which provides a service, like filecoin. Or you get somebody's approval of the block's contents, like in a permissioned blockchain.

I think we'll also see something where you do key-signing parties all at the same time as a way of providing sybil resistance. Or proof of having voted on whatever it is (the outcome of the vote would then go into the block).

Stake and work are just the easy ones to implement because they don't even try to be simultaneously useful.

Personally I'm not very excited about blockchains because I think global consistency is overkill for pretty much everything, and is in many cases harmful. But it's hard to take anyone seriously who classifies a technology as by-definition-useless. Its current forms are weak enough to defeat at face value, no need for propaganda.

As for the future ones... Maybe they be useful, we'll see.

[jazzyjackson]

Hm, thanks for the argument, I guess I'm turning it into semantics; filecoin and "permissioned block chains" sound more like reputation / web of trust systems. So to me it only becomes blockchain when there's some consensus mechanism not based on people making choices (because then we're just back to having a DB with auth...)

[__MatrixMan__]

It's a little different than a DB with auth. They have to make those choices in the clear, and they have to follow whatever rules are enforced by the protocol while they do it.

Unlike a DB with auth, if the process is trustworthy then the people don't have to be. Can such a thing exist? I dunno, but there's no evidence yet that it can't, and golly it would be cool if it did.

[cyberax]

"Permissioned blockchains" are basically isomorphic to git repositories. They certainly are useful, but they aren't "blockchains" in the regular sense.

[__MatrixMan__]

Well... git repositories with only one branch. But yeah, I'd argue that such things are blockchains in ever sense that matters. Or should we go ask the permissioned blockchains start calling themselves permissioned merkle linked lists?

[K0balt]

POW doesn’t have to be useless work. It can be useful work, so that mining actually creates a value tied to off chain economic systems. Then you have something that actually has value, and you can then use POS to give validators both a correct incentive alignment and a way to get paid for their work. Hybrid value backed POW for token creation with POS for validation creates a really good system for digital assets.

Sadly, extant systems for this are few because generating real value is actually challenging.

[cyberax]

> It can be useful work

It can be in theory, but in practice there are no tasks that fit the definition. All attempts to use something like protein folding ended up in failure.

[K0balt]

>no tasks….

Umm, I don’t think that’s true at all.

Digital content platform, for example, is a perfect task to generate outside value. Data storage is another example with many chains in that category thriving. Database is another, gpu compute/render, lots of useful tasks. You are basically saying that computational resources cannot be used to do valuable work, which is a premise that I think is questionable at best.

You don’t see a lot of hype around these projects because they aren’t intended to be speculative- teams in this space try to avoid wild speculation driven value cycles, because it is damaging to their economic models.

[cyberax]

> Digital content platform, for example, is a perfect task to generate outside value.

Yep. Storing CSAM materials against your will is great. Maybe interspersed with pirated movies. To add insult to injury, it's also not reliable enough for archival purposes for important data.

So far, I haven't seen any actually useful proof-of-work schemes that truly benefit the society.

[EGreg]

There are lots of other approaches - IOTA DAG, HashGraph, Ripple Consensus Process etc.

I am not a fan of blockchains, though. They are overkill for most uses. But here is an example of a non-blockchain system that doesn’t even require global consensus:

http://intercoin.org/technology.pdf

Also check out the Autonomi network

[cyberax]

It's not really going to work. Without a centralizing consensus, any such scheme is vulnerable to be drowned in forks.

A malicious notary network can simply flood the ledger with conflicting views. So clients will have to somehow find a set of notaries that is the "best".

Proof-of-stake means that there's effectively a vote on the set of "reliable" agents, and proof-of-work works because the malicious notaries can't outrace everyone else.

[EGreg]

Sorry, but you're not exactly an expert on this. There is a huge body of literature that says otherwise, and reference implementations.

You don't NEED "a centralizing consensus". IOTA did have one, called a "governor". And now they also did away with it.

I had a discussion with the CTO of Ripple (back then their chief cryptographer) David Schwartz about this exact issue in 2018, when I was also connecting with Leslie Lamport and others in the industry to discuss why and how global consensus was even needed

https://community.intercoin.app/t/intercoin-technology-conse...

You can also read this post here: https://community.intercoin.app/t/intercoin-technology-recov...

At the end of the post, it links to the mathematical results on arxiv if you're interested: https://arxiv.org/pdf/0802.0832v1

[cyberax]

> Sorry, but you're not exactly an expert on this. There is a huge body of literature that says otherwise, and reference implementations.

Yep, and none of them managed to solve the issue of resiliency without some kind of a stake.

From your own link:

> Intercoin’s ledger technology requires the sender to endorse a transaction after a supermajority of validators have approved it.

> Validators periodically check one another with “proof of resource” techniques.

Basically, it just moves the problem of validating individual transactions to validating the set of trusted notaries via proof-of-stake.

Just another rehash of crapcoin bullshit.

[EGreg]

There is no “the set” of trusted notaries

Each coin has a few notaries — not the majority of the network. Did you even glance at all at the arxiv paper?