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Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol [pdf] (2019)

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Re: Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol [pdf] (2019)

#51

Post by wmf »

gruez wrote: post #50
wmf wrote: post #24

Earlier quoted context omitted.

There are concerns (or concern trolls) about an attacker buying old keys for almost nothing, trashing the chain, then profiting by shorting. And there are concerns that the honest majority can't figure out how to switch to the honest fork.

>And there are concerns that the honest majority can't figure out how to switch to the honest fork. If that's always an option why bother with proof of stake in the first place? Just let it do whatever and switch to the "correct" fork once in a while!

Why not have the Supreme Court resolve every dispute? Because it's too expensive. Ultimately you can't exempt yourself from the judgement of society and the market. If you commit to a "most-work chain wins no matter what" policy it doesn't mean that chain will win economically.

Re: Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol [pdf] (2019)

#52

Post by endgame »

BluSyn wrote: post #28
martindale wrote: post #8

Proof of Stake not only replicates the same dynamics that Bitcoin was designed to eliminate (more wealth -> more power in system) but also can only be made secure against a maximum of ⅓ byzantine actors, compared to Proof of Work's superior ½. As for using it for Layer 1 systems, Andrew Poelstra nailed it in his conclusion [0]: "We showed that by depending only on resources within the system, proof of stake cannot be…

Fundamentally Proof-of-Work relies on the laws of thermodynamics and mathematics to secure the network. Fundamentally Proof-of-Stake relies on a high-level abstract game theory of social interactions between selfish players. One of these is not like the other.

wmf's snarky comment aside, I think there is something important here. What's the big markets story this week and last? A bunch of people intentionally acting "irrationally" fuelled by their spite. How much "smash the system" energy can PoS systems accept?

Re: Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol [pdf] (2019)

#53

Post by seibelj »

vbuterin wrote: post #36
martindale wrote: post #8

Proof of Stake not only replicates the same dynamics that Bitcoin was designed to eliminate (more wealth -> more power in system) but also can only be made secure against a maximum of ⅓ byzantine actors, compared to Proof of Work's superior ½. As for using it for Layer 1 systems, Andrew Poelstra nailed it in his conclusion [0]: "We showed that by depending only on resources within the system, proof of stake cannot be…

There's a couple things wrong here: > Proof of Stake not only replicates the same dynamics that Bitcoin was designed to eliminate (more wealth -> more power in system) There is no legitimate sense in which PoS _is_ an instance of "rich have more power and get richer" but PoW is not. In fact, PoW is _worse_ than PoS in this regard, because PoW has economies of scale (if someone with a $100k investment earns $10k/year,…

FYI - this is the founder of Ethereum

Re: Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol [pdf] (2019)

#54

Post by latchkey »

gruez wrote: post #48
latchkey wrote: post #33

Earlier quoted context omitted.

This doesn't work for ETH1, which is PoW, but memory hard, which ties the network to GPUs over ASICs due to the cost structure of producing ASICs. It is cheaper to buy an off the shelf GPU than it is to buy an ASIC. You also have to factor in the fact that the latest GPUs are not necessarily the best ROI. If you can get lower speed GPUs for a fraction of the cost, then your return on that is much faster. Of course, t…

> It is cheaper to buy an off the shelf GPU than it is to buy an ASIC. Ahh I guess all the people making/buying ETH mining ASICs must be out of their minds then? First result I found: https://www.coindesk.com/linzhi-rollout-long-awaited-ethereu...

You know how much that costs? I specifically mentioned ROI.

If you did the research into that one, it also only has 4.4gigs of ram. It will also slow down (aka: zombie mode) starting early November 2021 once the DAG gets large enough.

https://minerstat.com/dag-size-calculator

It takes about an hour of running it, just to start mining because the DAG generation takes so long.

By the way, Linzhi only sells to large customers because they've taken so long to produce this thing (years now) that they don't have enough money to front the production run.

They are also a super sketchy company. You should have seen the stuff they pulled during the ProgPoW debate.

Disclosure: I'm a very very large GPU miner and I'm deeply involved in this business.

Re: Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol [pdf] (2019)

#55

Post by latchkey »

wmf wrote: post #19
Geee wrote: post #18

Earlier quoted context omitted.

There's a difference. You can't physically centralize energy production. Local energy price will increase when more energy is used. This ensures that no one can get in a position of control. In PoS, it's possible to get > 50% ownership, and it's game over.

Is 70% of Bitcoin mining still in China?

Does it matter? As long as there is enough mining that isn't controlled by a single entity (mining in China isn't a single entity), then the network is secure.

Re: Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol [pdf] (2019)

#56

Post by latchkey »

gvhst wrote: post #46
Geee wrote: post #18

Earlier quoted context omitted.

There's a difference. You can't physically centralize energy production. Local energy price will increase when more energy is used. This ensures that no one can get in a position of control. In PoS, it's possible to get > 50% ownership, and it's game over.

That is true, but its easy to centralize private ASIC designs or in a more extreme case the underlying chip fabs. If TSMC wanted to control the Bitcoin network they'd have a fair shot given they have by far and away the best fabrication technology for high performance chips

You hit the nail on the head.

TSMC, Samsung and GlobalFoundries are the centralization points of all of mining because they produce the chips.

Good thing they like money and they are global corporations.

Re: Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol [pdf] (2019)

#57

Post by ilap »

martindale wrote: post #8

Proof of Stake not only replicates the same dynamics that Bitcoin was designed to eliminate (more wealth -> more power in system) but also can only be made secure against a maximum of ⅓ byzantine actors, compared to Proof of Work's superior ½. As for using it for Layer 1 systems, Andrew Poelstra nailed it in his conclusion [0]: "We showed that by depending only on resources within the system, proof of stake cannot be…

What is your point? One wrote something 5-years ago, when Ouroborus was not even invented at all, does it mean is it still hold?

Or do you want to believe that's still true because it would be very inconvenient to your biases (we all have our own biases) otherwise?

Sorry, I really did not want to be rude, just tried to find out whether you're trying to seek for the truth or just want to be right.

Re: Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol [pdf] (2019)

#58

Post by vbuterin »

jude- wrote: post #39
vbuterin wrote: post #36

Earlier quoted context omitted.

There's a couple things wrong here: > Proof of Stake not only replicates the same dynamics that Bitcoin was designed to eliminate (more wealth -> more power in system) There is no legitimate sense in which PoS _is_ an instance of "rich have more power and get richer" but PoW is not. In fact, PoW is _worse_ than PoS in this regard, because PoW has economies of scale (if someone with a $100k investment earns $10k/year,…

> There is no legitimate sense in which PoS _is_ an instance of "rich have more power and get richer" but PoW is not. In PoW, miners must sell their tokens to buy capital-intensive mining equipment and power to stay competitive. In PoS, stakers have no incentive to sell enough tokens to anyone who could turn around and stake them as a competitor, since that would cut into the seller's future staking rewards. > The 1/…

> Second, any consensus protocol can only remain live as long as there are no more than f faults out of 3f+1 replicas. This is again irrespective of the network model

We actually know of consensus protocols that require synchrony including between participants and clients that go up to 99% fault tolerance for both liveness and safety; in fact Lamport himself described one in his original paper (remember that it's "written messages" and not "oral messages" in his vocab that's the relevant category; these days public key cryptography is cheap and uncontroversial so there's no need to care about the "oral" case). There's also a table on page 291 in the 1988 DLS paper (see https://groups.csail.mit.edu/tds/papers/Lynch/jacm88.pdf, the "authenticated byzantine" row and the "synchronous" column) that gives an overview of the fault tolerance levels in various different cases.

The original definition of consensus did not have a notion of passive clients needing to learn the result, so the "active participants synchronous, passive clients asynchronous" model common in blockchain land was not really analyzed well back then. It turns out that with a synchronous network, the passive client requirement is what brings safety and liveness down from 99% to 50%. And it also happens that the 50% fault tolerance protocols are less fragile in the case that the synchrony assumption breaks temporarily.

Re: Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol [pdf] (2019)

#59

Post by vbuterin »

tryptophan wrote: post #49
vbuterin wrote: post #36

Earlier quoted context omitted.

There's a couple things wrong here: > Proof of Stake not only replicates the same dynamics that Bitcoin was designed to eliminate (more wealth -> more power in system) There is no legitimate sense in which PoS _is_ an instance of "rich have more power and get richer" but PoW is not. In fact, PoW is _worse_ than PoS in this regard, because PoW has economies of scale (if someone with a $100k investment earns $10k/year,…

Oooh. Its the man himself! Curious about what you think about ourboros/cardano! Pros cons vs eth?

When I last looked at Ouroboros it still had the property that there's only "one confirmation per slot", so you need to wait ~log(n) slots before an attacker has a <1/n probability of reversing the chain. I personally think that a good PoS system should strive to have hundreds of confirmations per slot the way eth2's LMD GHOST does. That said, it's very possible that there's an improved version of Ouroboros that already does this and I just haven't caught up to it yet.

Re: Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol [pdf] (2019)

#60

Post by latchkey »

pmohun wrote: post #43
sp821543 wrote: post #21

Earlier quoted context omitted.

Aren't 65% of all bitcoin miners in China? Couldn't the CCP sabotage the network at any time? Say, a month before the launch of their digital currency? https://cbeci.org/mining_map

This specific visualization is limited to 37% of the hash power on the network. It's possible that it is a representative sample, but I don't think we can assume that.

Even better, it is limited to pools that primarily operate in China. I really wish someone would turn off that link. It is really awkwardly bad and mis-quoted a lot.
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