Besides proof-of-stake, there's also a coin that tries (tried?) a proof-of-work with greater public utility: Primecoin [1]. It creates Cunningham chains of prime numbers [2].

[1] https://en.wikipedia.org/wiki/Primecoin

[2] https://en.wikipedia.org/wiki/Cunningham_chain

"Useful PoW" is a dead end. Good PoW functions require properties that rule out real world useful problems.

Wasn't there also like CureCoin that unfolds proteins for medical application?

Yes, and there's also SolarCoin which rewards users for producing renewable energy. The problem is that these coins are centralised, so while they may be very useful for what they do, they don't solve the same problem as proof-of-work coins which aim to be decentralised.

there is also gridcoin but they are not useful pow. they are proof of stake where the stake is the amount of contribution towards boinc projects and the likes, and they are affected by the oracle problem

Is that useful for anything other than the Primecoin?

Wouldn't work, the security of PoW explicitly relies on waste. If the external value from mining is X and an attack costs Y, the net cost of the attack is X-Y=Z, so the real security is Z, the waste portion.

Not necessarily waste, no. It just needs to be unpredictable.

I think PrimeCoin was a great example of a PoW that had very small but non-zero value.

From 2015: http://www.truthcoin.info/blog/pow-cheapest/

Incorrect. The supposed MR=MC law means that the entire economy is zero-sum and wealth creation is impossible. His reasoning also directly translates to real world physical security, as in, if you want to protect wealth worth $1000 from theft, according to him you have to spend $1000-epsilon, otherwise someone is going to outspend you and steal it. Fortunately, that's not how the world works.

Visual illustration of the asymmetric security in action: https://www.pohjoiseen.fi/wp-content/uploads/2016/03/2083960...

Fortunately, we get asymmetric security through laws and criminal punishment rather than machine gun bunkers.

Also, MR=MC doesn’t imply that wealth is never created, it just means that it can’t be created purely through exchanging commodities.

Nothing special about commodity exchange. The difference between marginal revenue and marginal cost is marginal wealth creation (destruction if negative). A world in which MR=MC is in a global maximum and no improvement is possible - any state changes imposed externally can either lead to the same score ('wealth') or make it worse.

In other words, he first assumes that no improvement is possible, and then indeed manages to show that, according to the assumptions, no improvement is possible.

Ethereum proof of stake is coming and should fix that elegantly.

I feel like that’s been coming any day now since about 2014.

And seems like a TERRIBLE idea, anyway. The rich get richer, built right into the system!

PoW is exactly the same. The rich can afford the most hardware and electicity. PoS just short circuits the burning power step. It's also the same as bank interest.

PoW provides significant economies of scale for those with lots of scale and makes mining with a single GPU a waste of time. PoS doesn't offer much economies of scale at all as the main cost is the ETH, so it's much fairer to smaller validators.

When you put your money in a bank, it doesn’t just sit there. Deposits, while possibly not the most efficient way to do it, support useful economic activity.

Proof of work is also terrible, obviously. Proof of stake seems like an awful thing to _aspire_ to, tho.

The minimum stake of 32 eth is probably going to require something like a laptop to run. Those with larger stakes are going to need to devote more computer resources to the network.

32 ETH is ~$4,800 at today's price of $151.07[1]. What's the expected "payout" for this stake?

[1] CoinMarketCap used as source.

Expected payout depends on the total amount staked. With a large amount staked it's only a couple percent annually; with a small amount it's up to 18% annually. The idea is an equilibrium will be reached in the middle somewhere.

How are participants prevented from simply splitting up their stakes?

The return isn't based on how much you stake. It's based on how much everybody stakes. It's targeting an approximate amount of total ETH staked and doesn't really care how much is staked by each individual.

That's an interesting formula.

More than the interest paid on savings accounts.

Proof-of-stake has been in use in other non-Ethereum cryptocoins for a very long time [1] [2]. In Nano's case, there's no transaction fees paid to stakeholders (nor their delegated representatives).

[1] https://en.wikipedia.org/wiki/Peercoin

[2] https://en.bitcoinwiki.org/wiki/Nano

Nano consensus mechanism is called Open Representative Voting (ORV). It has similar sides to proof-of-stake, but differs in important places. e.g. it is less a "stake" than a voting weight that the users themselves distribute to nodes of their choice (or their own). ORV's self-description at:

https://docs.nano.org/glossary/#open-representative-voting-o...

> or their own

Sure, it's an optionally-delegated-proof-of-stake. In practice, most do delegate their stake. But at the end of the day the "voting weight" that secures transactions is majority stake and not a proof of work.

Phase 0 of Ethereum v2 arrives in Q1 2020. Coming since 2014 but finally arriving :)

Proof of stake reduces the issuance of new ETH to pay for the cost of securing the network. It's cheaper than paying miners. And anybody can buy ETH to stake so it's more egalitarian than mining which requires economies of scale in hardware and electricity.

Doesn't phase 0 exclude the ability to transfer money? The whole point of a "currency"???

My understanding is that Phase 0 features the ability to lock up eth and take it out of circulation.

You might consider if perhaps the parties in control of that system have a different idea of its point than you do.

Correct. Phase 0 isn't useful by itself and phase 1 isn't that useful either. Phase 2 is when people can actually start using ETH2 instead of ETH1.

PoS would be more egalitarian if it was that way from the start, however as it is transitioning from PoW this means that anyone that bought in early, now has an opportunity to solidify their position. For new entrants to reach the same level of investment would be significantly higher. So the ETH rich get richer and it widens the gap.

The rich get richer in proof of work, too. It's not like those giant mining rigs are free.

It's also true in bank accounts; the more money deposited, the more interest you earn. At least in proof of stake everybody gets the same interest rate regardless of deposit size. Banks generally give better rates to larger accounts.

Ethereum wasn't launched until July 2015 so there's one inaccuracy. Also given you're on HN you should likely be aware that (a) timelines are difficult to estimate and often things take much longer than you thought, even more so with being the first to do something, (b) there's a lot of discussion and review for financial software, (c) it's much harder to change the carriage of a moving train

(d) performing work on a moving train is a bug, not a feature.

Decred set up it's mixed PoS/PoW so that there is an opportunity cost to staking - your funds are locked for a random amount of time up to several months. The staking rewards are also not enough to keep indefinitely staking. Your share of stake will continuously decrease, and, aside from ticket splitting, you would need to acquire more decred along the way to continue staking at the same level.

> is coming

Yeah that was 5 years ago too if you don't remember.

It's an incredibly difficult problem and anyone claiming to have actually solved it in a decentralised way that proof-of-work did is a charlatan.

Given all the money slushing around in cryptocurrency looking for a problem to solve I'd argue it's an intractable issue that needs yet another breakthrough rather than marketing and bubble hype.

I hear it's powered by cold fusion and Half Life 3.

50% since they announced a third Half Life game.

I'm disappointed that PrimeCoin didn't really catch on. It's mathematically sound, relatively quantum safe, and produces useful output. Any improvements to factoring or finding prime chains would be genuine advances in the field, whether algorithm or hardware (ASIC) based.

Need to mention GridCoin because context. Uses BOINC for proof-of-work.