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> it might be possible to achieve wide enough consensus among stakers in Western countries to punish China (for some reason), e.g. willingly losing part of thei

> it might be possible to achieve wide enough consensus among stakers in Western countries to punish China (for some reason), e.g. willingly losing part of their stakes to empty major Chinese wallets. According to Ethereum's PoS implementation, this would require more than 33% of all staked Ethereum coordinating with modified clients in order to pull off. Then, another percentage of the stake adding up to 66% would have to be complicit in the attack, rather than actively defending against it by refusing to finalize blocks. Compare this to PoW, where only 51% of hashrate needs to be participating/complicit to censor certain transactions, the other 49% have no way of fighting back, and the only tool the community has to fork away is to change the PoW algorithm. Because of this, I actually believe PoS is more resistant than PoW to these kinds of attacks.

fredfoobar 5y ago
> Compare this to PoW, where only 51% of hashrate needs to be participating/complicit to censor certain transactions, the other 49% have no way of fighting back, and the only tool the community has to fork away is to change the PoW algorithm. This is just such a small part of the whole equation. 1. They can't continuously attack with this, as you need to expend energy as long as you want to continue with the attack. 2. Even if you have majority hash-rate, you can't change the rules of the system (this has already happened)
- everfree 5y ago
  1. Under PoW, a 51% attacker can continuously attack profitably. All the energy they expend gets returned as mining rewards just like normal, and they can potentially even (up to) double their rewards if they censor the other 49%. The only way to stop this aside from changing the PoW algorithm is to physically locate and seize the mining rigs. 2. Majority stakers can't change the rules of the system either.
  - ByThyGrace 5y ago
    > All the energy they expend gets returned as mining rewards just like normal Is that because the mined blocks themselves are still valid (i.e. the hashes check out), regardless of the presence of an attacker? But then how does it help the attacker in an economical sense? Doesn't the rest of the network know that the new 51% blocks are tainted, so to speak?
    - everfree 5y ago
      >Is that because the mined blocks themselves are still valid (i.e. the hashes check out), regardless of the presence of an attacker? Yes. A censorship attack is just that - it's about mining valid blocks that ignore transactions from a certain party, and/or ignoring blocks from other block producers. > But then how does it help the attacker in an economical sense? If an attacker has 60% and censors all other block producers (40%), those other block producers won't be able to earn any mining rewards because teh 60% can continuously orphan the blocks they produce, putting them on non-longest-chain (invalid) forks. In writing my last reply I forgot that difficulty adjustment only happens every 14 days (I can't remember how long it is with Ethereum's PoW, but let's take Bitcoin's PoW as an example), so it's likely that the attacker wouldn't earn any more mining rewards than an honest miner at first. When that difficulty adjustment happens though, if the miner had been censoring for a good part of the past 14 days, the network would adjust to "consider their 60% the entire hashrate of the network", thus the attacker would start earning the other 40% of rewards for themselves in addition to the rewards they are supposed to earn. > Doesn't the rest of the network know that the new 51% blocks are tainted, so to speak? It becomes a very messy, subjective problem. For every block, you would have to prove whether the block producer is part of the censorship attack or just has an incomplete view of the network, which is an intractable computing problem without some sort of subjective heuristic requiring multiple network viewpoints and trusted parties.
Taek 5y ago
In practice a PoS network tends to have a participation rate of between 10% and 30%, and the 2-3 largest exchanges collectively tend to own between 10% and 50% of the total supply. And then also in practice most of the staking is performed by a small number of outsourced staking firms, which increases the power concentration even more. And it also makes hardforks more traumatic because your economy and your consensus builders are fundamentally intertwined. You can't fork an exchange off of the network without also disrupting every single user that parks funds on that exchange. The same concern doesn't exist with PoW mining.
- everfree 5y ago
  >You can't fork an exchange off of the network without also disrupting every single user that parks funds on that exchange. Anyone who willingly opts into staking on a shady exchange, agreeing to a contract saying that they might be slashed, needs to be prepared to be slashed. On the other hand, any exchange that automatically opts user deposits into staking without notifying them should be criminally liable. That's a big breach of user trust.
  - javitury 5y ago
    > On the other hand, any exchange that automatically opts user deposits into staking without notifying them should be criminally liable. One of the selling points of cryptocurrencies is that they make financial transactions and contracts possible without depending on a central authority.
  - irae 5y ago
    > On the other hand, any exchange that automatically opts user deposits into staking without notifying them should be criminally liable. I never realized this could even happen. And this is a HUGE problem for PoS if I am understanding this correctly. Because Exchanges don't even settle the transactions that often on chain, and could totally do this without user knowledge and then say they did with someone else's coins. You can't even prove it.
    - 5y ago

fredfoobar 5y ago

> Compare this to PoW, where only 51% of hashrate needs to be participating/complicit to censor certain transactions, the other 49% have no way of fighting back, and the only tool the community has to fork away is to change the PoW algorithm. This is just such a small part of the whole equation. 1. They can't continuously attack with this, as you need to expend energy as long as you want to continue with the attack. 2. Even if you have majority hash-rate, you can't change the rules of the system (this has already happened)

everfree 5y ago
1. Under PoW, a 51% attacker can continuously attack profitably. All the energy they expend gets returned as mining rewards just like normal, and they can potentially even (up to) double their rewards if they censor the other 49%. The only way to stop this aside from changing the PoW algorithm is to physically locate and seize the mining rigs. 2. Majority stakers can't change the rules of the system either.
- ByThyGrace 5y ago
  > All the energy they expend gets returned as mining rewards just like normal Is that because the mined blocks themselves are still valid (i.e. the hashes check out), regardless of the presence of an attacker? But then how does it help the attacker in an economical sense? Doesn't the rest of the network know that the new 51% blocks are tainted, so to speak?
  - everfree 5y ago
    >Is that because the mined blocks themselves are still valid (i.e. the hashes check out), regardless of the presence of an attacker? Yes. A censorship attack is just that - it's about mining valid blocks that ignore transactions from a certain party, and/or ignoring blocks from other block producers. > But then how does it help the attacker in an economical sense? If an attacker has 60% and censors all other block producers (40%), those other block producers won't be able to earn any mining rewards because teh 60% can continuously orphan the blocks they produce, putting them on non-longest-chain (invalid) forks. In writing my last reply I forgot that difficulty adjustment only happens every 14 days (I can't remember how long it is with Ethereum's PoW, but let's take Bitcoin's PoW as an example), so it's likely that the attacker wouldn't earn any more mining rewards than an honest miner at first. When that difficulty adjustment happens though, if the miner had been censoring for a good part of the past 14 days, the network would adjust to "consider their 60% the entire hashrate of the network", thus the attacker would start earning the other 40% of rewards for themselves in addition to the rewards they are supposed to earn. > Doesn't the rest of the network know that the new 51% blocks are tainted, so to speak? It becomes a very messy, subjective problem. For every block, you would have to prove whether the block producer is part of the censorship attack or just has an incomplete view of the network, which is an intractable computing problem without some sort of subjective heuristic requiring multiple network viewpoints and trusted parties.

Taek 5y ago

In practice a PoS network tends to have a participation rate of between 10% and 30%, and the 2-3 largest exchanges collectively tend to own between 10% and 50% of the total supply. And then also in practice most of the staking is performed by a small number of outsourced staking firms, which increases the power concentration even more. And it also makes hardforks more traumatic because your economy and your consensus builders are fundamentally intertwined. You can't fork an exchange off of the network without also disrupting every single user that parks funds on that exchange. The same concern doesn't exist with PoW mining.

everfree 5y ago
>You can't fork an exchange off of the network without also disrupting every single user that parks funds on that exchange. Anyone who willingly opts into staking on a shady exchange, agreeing to a contract saying that they might be slashed, needs to be prepared to be slashed. On the other hand, any exchange that automatically opts user deposits into staking without notifying them should be criminally liable. That's a big breach of user trust.
- javitury 5y ago
  > On the other hand, any exchange that automatically opts user deposits into staking without notifying them should be criminally liable. One of the selling points of cryptocurrencies is that they make financial transactions and contracts possible without depending on a central authority.
- irae 5y ago
  > On the other hand, any exchange that automatically opts user deposits into staking without notifying them should be criminally liable. I never realized this could even happen. And this is a HUGE problem for PoS if I am understanding this correctly. Because Exchanges don't even settle the transactions that often on chain, and could totally do this without user knowledge and then say they did with someone else's coins. You can't even prove it.
  - 5y ago