11 ms·

I don't get proof of stake. What's stopping anyone from presenting a new chain made up of thousands of fake transactions? And why wouldn't such chain be accepte

I don't get proof of stake. What's stopping anyone from presenting a new chain made up of thousands of fake transactions? And why wouldn't such chain be accepted by the network? Is it just "checkpoints" hardcoded in the software that don't allow this?

whoooooo123 4y ago
It's bullshit: https://yanmaani.github.io/proof-of-stake-is-a-scam-and-the-people-promoting-it-are-scammers/ https://yanmaani.github.io/proof-of-stake-is-a-scam-and-the-...
- 6c737133 4y ago
  A magnificently misinformed waste of bytes. Thanks for sharing.
  - papa-whisky 4y ago
    I can't tell if "waste of bytes" is referring to the blog post shared by GP, or to proof of stake as a whole. If the former; as someone with little knowledge of cryptocurrency the post read fairly convincingly to me. In what ways is it misinformed?
    - ikt 4y ago
      You can read more here when it was posted previously: https://news.ycombinator.com/item?id=29366310 https://news.ycombinator.com/item?id=29366310 Basically he built up a strawman and then burned it to the ground.
      - setr 4y ago
        I’m scouring through the comment chain but I’m not really finding such a definitive response. I’m assuming you’re referring to the first chain of comments, but that seems to boil down to “the attack exists but it’s fine because to successfully attack the network would destroy the network, and with it any profit you’ve made in the attack; thus you cannot profit” — but this is directly addressed by the “nothing at stake” section of the article; if I can attack the successfully attack the network, and liquidate my position before the network implodes, I win (which PoW mitigates by making the 51% attack itself prohibitively expensive). Which hardly seems unreasonable, because the network imploding is a feature of humans losing trust in the network and abandoning it — in compute-land, an eternity. In my skimming, I can’t find anything that addresses this — and especially not anything that merits describing TFA as a strawman.
        ChadNauseam 4y ago
        To execute that attack, you would need validators to sign blocks on your forked chain. Presumably they’ve already signed blocks on the main chain, so they’d be double-signing, which instantly costs them a very large amount of money on both chains (when you double sign, people can submit proofs of that on either chain, causing you to get your stake slashed.) That’s what makes the attack you’re imagining prohibitively expensive. If you’re still worried about that happening to some ETH you received, wait for the blocks to finalize. Once they have, they will never be reverted without a change to the protocol.
        everfree 4y ago
        The writer of the article supposes that it's a critical vulnerability that a validator can come up with an "equally valid" alternate history for Ethereum that stems from a fork several months prior, after the validator has already withdrawn their stake from the canonical chain to prevent slashing. In reality, everyone just ignores the attacker's chain, because it attempts to rewrite not seconds, minutes, or days of canonical history (periods of time short enough that the identity of the canonical chain might be in question), but many months of history that the entire world has already agreed on and that node software refuses to reorganize the chain past. This post by Vitalik in 2014, shortly before the launch of Ethereum, explains why this "weak subjectivity" property of PoS is not nearly as problematic as PoW proponents make it out to be. https://blog.ethereum.org/2014/11/25/proof-stake-learned-love-weak-subjectivity/ https://blog.ethereum.org/2014/11/25/proof-stake-learned-lov...
samkon 4y ago
Any node that did this would have their stake slashed by the rest of the network, because it would be easy to prove that the chain was invalid. The network finalizes the blocks that are added to the chain, there are no deep chain reorgs like in bitcoin - so any significant alternate history is easily identified.
pkulak 4y ago
Nothing. But nothing moves forward without consensus. So you'd need 51% of the network to agree with your made up chain, which would mean controlling about $100 billion in Eth. And then you've managed to destroy a network that you have $100 billion wrapped up in, so... good job? And if you try with less than 51% and the rest of the network slaps you down, you lose your stake (or some portion of it).
- giaour 4y ago
  > So you'd need 51% of the network to agree with your made up chain, which would mean controlling about $100 billion in Eth. Does that sum assume that every coin will be staked? As I understand it, coins staked for validation are held in escrow and can’t be used for transactions until the validator node unstakes the coins. Surely only a small percentage of coins will be staked at any given time.
  - ChadNauseam 4y ago
    There is $200B ETH staked already
    - myroon5 4y ago
      All ETH is worth slightly less than $200B: https://coinmarketcap.com/currencies/ethereum/ https://coinmarketcap.com/currencies/ethereum/ and most of it is not staked
bhaak 4y ago
All the nodes that have been online long enough will know that the fake chain is fake. Because it doesn't match the state that they have been observing all along. So as long as you have no extended downtime, your nodes know what the right chain has to look like. Ethereum dynamically adds checkpoints so that block reorgs can't reach too far into the past but that is mostly a convenience function as it alone couldn't solve this issue. Now, there is a problem if you are a new participant. Then you can't decide which chain is the right one. You could observe for a while and choose the one that has more validators but in theory, there's the possibility that there's a contentious hard fork going on. In this case you need to get the information which chain is the right one from outside sources. E.g. like your preferred exchange or the official subreddit. This is the most glaring difference between POS and POW. With POW, you don't need any outside information as you can just verify which chain needed more work to be created and this is by definition the correct one. POW leverages physics to be completely self contained for the price of energy consumption.
- betwixthewires 4y ago
  This problem is overstated IMO. Choosing the one with the most validators is closely analogous to choosing the chain with the most work i.e. the one with the most hash power. And with algorithmic difficulty adjustment in PoW, you don't pick the chain with the headers with the most 0s preceding, you pick the longest chain. A longer chain with a sudden difficulty adjustment is an obvious invalid chain, but I digress The bigger problems for me are the nothing st stake problem. Why pick one chain when you're new? Just pick both, it costs virtually nothing, and when you figure out which one is more profitable to you, just let the stake in the other one get slashed. Validators can help an attack on the network just in case it becomes profitable, and if it doesn't they lose nothing, because they incur no ongoing costs in the real world to do so.
  - doomroot 4y ago
    I’m not sure about Ethereum PoW, but in Bitcoin you absolutely pick the chain with the most work not the longest chain that’s a consensus rule. This is how bitcoin/PoW avoids weak subjectivity, the problem described by the parent comment.

whoooooo123 4y ago

It's bullshit: https://yanmaani.github.io/proof-of-stake-is-a-scam-and-the-people-promoting-it-are-scammers/ https://yanmaani.github.io/proof-of-stake-is-a-scam-and-the-...

6c737133 4y ago
A magnificently misinformed waste of bytes. Thanks for sharing.
- papa-whisky 4y ago
  I can't tell if "waste of bytes" is referring to the blog post shared by GP, or to proof of stake as a whole. If the former; as someone with little knowledge of cryptocurrency the post read fairly convincingly to me. In what ways is it misinformed?
  - ikt 4y ago
    You can read more here when it was posted previously: https://news.ycombinator.com/item?id=29366310 https://news.ycombinator.com/item?id=29366310 Basically he built up a strawman and then burned it to the ground.
    - setr 4y ago
      I’m scouring through the comment chain but I’m not really finding such a definitive response. I’m assuming you’re referring to the first chain of comments, but that seems to boil down to “the attack exists but it’s fine because to successfully attack the network would destroy the network, and with it any profit you’ve made in the attack; thus you cannot profit” — but this is directly addressed by the “nothing at stake” section of the article; if I can attack the successfully attack the network, and liquidate my position before the network implodes, I win (which PoW mitigates by making the 51% attack itself prohibitively expensive). Which hardly seems unreasonable, because the network imploding is a feature of humans losing trust in the network and abandoning it — in compute-land, an eternity. In my skimming, I can’t find anything that addresses this — and especially not anything that merits describing TFA as a strawman.
      - ChadNauseam 4y ago
        To execute that attack, you would need validators to sign blocks on your forked chain. Presumably they’ve already signed blocks on the main chain, so they’d be double-signing, which instantly costs them a very large amount of money on both chains (when you double sign, people can submit proofs of that on either chain, causing you to get your stake slashed.) That’s what makes the attack you’re imagining prohibitively expensive. If you’re still worried about that happening to some ETH you received, wait for the blocks to finalize. Once they have, they will never be reverted without a change to the protocol.
      - everfree 4y ago
        The writer of the article supposes that it's a critical vulnerability that a validator can come up with an "equally valid" alternate history for Ethereum that stems from a fork several months prior, after the validator has already withdrawn their stake from the canonical chain to prevent slashing. In reality, everyone just ignores the attacker's chain, because it attempts to rewrite not seconds, minutes, or days of canonical history (periods of time short enough that the identity of the canonical chain might be in question), but many months of history that the entire world has already agreed on and that node software refuses to reorganize the chain past. This post by Vitalik in 2014, shortly before the launch of Ethereum, explains why this "weak subjectivity" property of PoS is not nearly as problematic as PoW proponents make it out to be. https://blog.ethereum.org/2014/11/25/proof-stake-learned-love-weak-subjectivity/ https://blog.ethereum.org/2014/11/25/proof-stake-learned-lov...

samkon 4y ago

Any node that did this would have their stake slashed by the rest of the network, because it would be easy to prove that the chain was invalid. The network finalizes the blocks that are added to the chain, there are no deep chain reorgs like in bitcoin - so any significant alternate history is easily identified.

pkulak 4y ago

Nothing. But nothing moves forward without consensus. So you'd need 51% of the network to agree with your made up chain, which would mean controlling about $100 billion in Eth. And then you've managed to destroy a network that you have $100 billion wrapped up in, so... good job? And if you try with less than 51% and the rest of the network slaps you down, you lose your stake (or some portion of it).

giaour 4y ago
> So you'd need 51% of the network to agree with your made up chain, which would mean controlling about $100 billion in Eth. Does that sum assume that every coin will be staked? As I understand it, coins staked for validation are held in escrow and can’t be used for transactions until the validator node unstakes the coins. Surely only a small percentage of coins will be staked at any given time.
- ChadNauseam 4y ago
  There is $200B ETH staked already
  - myroon5 4y ago
    All ETH is worth slightly less than $200B: https://coinmarketcap.com/currencies/ethereum/ https://coinmarketcap.com/currencies/ethereum/ and most of it is not staked

bhaak 4y ago

All the nodes that have been online long enough will know that the fake chain is fake. Because it doesn't match the state that they have been observing all along. So as long as you have no extended downtime, your nodes know what the right chain has to look like. Ethereum dynamically adds checkpoints so that block reorgs can't reach too far into the past but that is mostly a convenience function as it alone couldn't solve this issue. Now, there is a problem if you are a new participant. Then you can't decide which chain is the right one. You could observe for a while and choose the one that has more validators but in theory, there's the possibility that there's a contentious hard fork going on. In this case you need to get the information which chain is the right one from outside sources. E.g. like your preferred exchange or the official subreddit. This is the most glaring difference between POS and POW. With POW, you don't need any outside information as you can just verify which chain needed more work to be created and this is by definition the correct one. POW leverages physics to be completely self contained for the price of energy consumption.

betwixthewires 4y ago
This problem is overstated IMO. Choosing the one with the most validators is closely analogous to choosing the chain with the most work i.e. the one with the most hash power. And with algorithmic difficulty adjustment in PoW, you don't pick the chain with the headers with the most 0s preceding, you pick the longest chain. A longer chain with a sudden difficulty adjustment is an obvious invalid chain, but I digress The bigger problems for me are the nothing st stake problem. Why pick one chain when you're new? Just pick both, it costs virtually nothing, and when you figure out which one is more profitable to you, just let the stake in the other one get slashed. Validators can help an attack on the network just in case it becomes profitable, and if it doesn't they lose nothing, because they incur no ongoing costs in the real world to do so.
- doomroot 4y ago
  I’m not sure about Ethereum PoW, but in Bitcoin you absolutely pick the chain with the most work not the longest chain that’s a consensus rule. This is how bitcoin/PoW avoids weak subjectivity, the problem described by the parent comment.