Proof of stake is incapable of producing a consensus • Hacker News Board

Re: Proof of stake is incapable of producing a consensus

#71

Post by rich_sasha » Sun, Nov 28, 2021, 7:22 AM UTC

My general observation is that blockchains are, at best, secure in the same way https is secure. Yes I have padlock icon on the browser address bar, and my connection is secure, there’s a security certificate, but the whole thing can still be a scam.

Who personally verifies every contract they use? Wallet implementation? Cold wallets are closed-source, trust-me devices, maybe with a security certificate from a centralised, government-linked security org.

The strongest link in any security chain is not irrelevant, but the whole system is really not perfectly trustless anyway.

Re: Proof of stake is incapable of producing a consensus

#72

Post by betwixthewires » Sun, Nov 28, 2021, 7:22 AM UTC

mNovak wrote: post #44

Am I understanding this correctly; is the threat model that a block signer, some time later after liquidating their stake, can go and publish arbitrary versions of that older block?

Yes, but it is a little more than that: that future nodes will not be able to distinguish these two blocks without relying on some authoritative source for the canonical chain, thus introducing centralization to the game environment.

Re: Proof of stake is incapable of producing a consensus

#73

Post by yuliyp » Sun, Nov 28, 2021, 7:23 AM UTC

crazypython wrote: post #9

barbegal wrote: post #5

Proof of work has always had an economic flaw that you could theoretically temporarily rent enough mining power to perform double spends of more value than the cost of renting those devices. But this attack has never been performed because the reality of all these cryptocurrencies is that the security depends only relatively weakly on proof of work. Instead it relies on trust between the main stakeholders: miners, bi…

https://www.crypto51.app/ To execute a double spend, you the one sending the transaction and the miner must coordinate. For large transactions, it is recommended to wait for six confirmations. (six blocks that agree with the transaction and have not been 51%ed.) The 1 hour 51% cost of Bitcoin is 1.9m$. However, you would need much more time than that to find six consecutive blocks alone, without the help of the netwo…

I don't see how more confirmations makes it exponenrially harder to mount a 51% attack: you just need to be mining faster privately than the remaining community until you (a) have a lead, and (b) have maintained that lead for the confirmation window.

Re: Proof of stake is incapable of producing a consensus

#74

Post by betwixthewires » Sun, Nov 28, 2021, 7:24 AM UTC

EGreg wrote: post #69

This is like two homeless people arguing who is richer. Yes both PoW, PoS solve the double-spend problem, but in a brute-force way. And they never really get rid of the ambiguity of which chain is the one to go by. They just aggregate all the little ambiguities into one or another consistent version of history (a chain) and let them duke it out by massive electricity or stake or whatever. But at any moment, someone c…

> LMAO

I don't get your criticism. Why does requiring gossip to every node cause centralization? Why does everyone having the current state of everything cause centralization?

Re: Proof of stake is incapable of producing a consensus

#75

Post by anonporridge » Sun, Nov 28, 2021, 7:24 AM UTC

pshc wrote: post #34

Is this FUD from Bitcoin maximalists? > That key is valid to sign any number of versions of, let’s say, block #200, and there is no objective, system-internal standard for which version is legitimate, other than “the one that was published first”. The real block #200 will have hundreds of attestations courtesy of randomly-selected validators, each of those signatures attesting to its validity and finality.

Attestations don't have a real world economic cost that can be validated trustlessly within the system. If you compromise or coerce enough validators, you can rewrite the history for no cost.

That's what PoW provides that PoS just doesn't. Immutability.

In fact, I would argue that one of the most important products of bitcoin, is providing the hardest, most immutable database human civilization has ever created. We could theoretically lose it and we could control and manipulate what goes into it going forward, but once a piece of data gets confirmed and buried under a few days worth of bitcoin's PoW, it can never be changed or removed from the blockchain. This is a severely undervalued use case in my mind.

I suspect that most PoS coins will eventually decide to periodically peg themselves into bitcoin's blockchain to timelock their blockchains and provide some immutability to their users.

Having said that, humanity probably only needs one PoW blockchain. Bitcoin.

Re: Proof of stake is incapable of producing a consensus

#76

Post by Laforet » Sun, Nov 28, 2021, 7:25 AM UTC

comex wrote: post #60

ricardolopes wrote: post #49

Earlier quoted context omitted.

The Bitcoin Core client includes a hardcoded list of DNS servers that point to thousands of nodes. These lists get updated frequently by different people. Other clients may use other lists. What is the threat model you're suggesting here, exactly? Do you know any other way to bootstrap a peer to peer network without centralised authorities? All network participants are forced to verify the full chain from genesis. So…

> Do you know any other way to bootstrap a peer to peer network without centralised authorities? I’m not the parent, but – no, I don’t. But that’s exactly the point. The need to bootstrap from centralized authorities is what’s supposedly so bad about weak subjectivity in proof-of-stake. Yet in practice, it’s needed with proof-of-work as well.

Hi Nick, very well said and this is precisely my point as well.

Satoshi tried to convince us that we could decentralise trust by doing honest work instead of relying on authority. It turns out that doing work is actually pretty hard, people are lazy, and security is still the nemesis of efficiency.

Re: Proof of stake is incapable of producing a consensus

#77

Post by hanniabu » Sun, Nov 28, 2021, 7:25 AM UTC

_2d30 wrote: post #21

I'm blown away by how quickly this rose on HN and how unconvincing it is.

It's a fud piece by a bitcoin maxi and HN is anti-crypto so it resonates with them and gives the echo chamber some good confirmation bias kool aid.

Re: Proof of stake is incapable of producing a consensus

#78

Post by pshc » Sun, Nov 28, 2021, 7:26 AM UTC

ricardolopes wrote: post #57

pshc wrote: post #34

Is this FUD from Bitcoin maximalists? > That key is valid to sign any number of versions of, let’s say, block #200, and there is no objective, system-internal standard for which version is legitimate, other than “the one that was published first”. The real block #200 will have hundreds of attestations courtesy of randomly-selected validators, each of those signatures attesting to its validity and finality.

The block 200 will be adding validation to the previous blocks, and will be validated by the future ones. Without other types of checks, nothing stops you from rewriting the previous 199 blocks and using block 200 to validate them. This is not FUD, it's the most obvious PoS flaw, called long range attack, and the reason PoS chains often need more checks to be more trustworthy (e.g. keeping hardcoded checkpoints, choo…

Here’s a recent ETH2 block: https://beaconcha.in/block/2604970#votes

It was voted for by 8000+ validators. Many of them have been validating since beacon chain genesis a year ago. There are like 260k validators active right now.

I find it highly unlikely some entity is going to come along and try to pretend their alternate history, with a whole new set of hundreds of thousands of validators (which wouldn’t be supported by any ETH1 deposits) and millions of signatures signed by 260k freshly generated public keys, is in any way legitimate.

Re: Proof of stake is incapable of producing a consensus

#79

Post by hanniabu » Sun, Nov 28, 2021, 7:26 AM UTC

suikadayo wrote: post #67

sp332 wrote: post #26

Earlier quoted context omitted.

Well, how many times has it been delayed? Clearly it's not all sunshine and rainbows.

What’s delayed? Beacon chain has been running on mainnet since last December-ish. http://beaconcha.in

But-but-but! frustrated by facts

Re: Proof of stake is incapable of producing a consensus

#80

Post by adnzzzzZ » Sun, Nov 28, 2021, 7:27 AM UTC

CraftingLinks wrote: post #19

Can't wait for the day all PoW mining activities are declared illegal. To be honest, I don't understand why it hasn't been banned already. Sweden has recently called for a EU wide ban because it identified PoW mining as a threat to transition their economy to renewable energy. https://www.fi.se/en/published/presentations/2021/crypto-ass...

Doesn't seem like everyone in Sweden agrees with that opinion, especially not the people actually running energy companies: https://twitter.com/ercwl/status/1457114531314995206