4 ms·

>Proof if work is a solution where you do not have to trust anyone, as the block is won by the person who finds the right math result, essentially a lottery. T

by 0x64 6y ago

>Proof if work is a solution where you do not have to trust anyone, as the block is won by the person who finds the right math result, essentially a lottery. The same applies to Eth2's PoS network, as block proposers are randomly selected with on-chain randomness. Block rewards are also not a major source of income for a staker on Eth2 — the majority of income (>90%) comes from simply attesting the chain correctly. This attesting occurs once an epoch for every validator, or every 32 blocks. >Proof if stake is either really proof of work that is less secure and obscured, or more often dimply giving the creators of the coin the power and your trust.... PoS vs. PoW is really only a matter of how you ensure your chain can't be attacked. For PoW it's equipment cost, burnt electricity, and opportunity cost for losing rewards due to attacking the chain. For PoS, the security is ensured through a high-enough buy-in cost (32 Eth), and penalizing attackers harshly through slashing. You can imagine how expensive it would be to accumulate enough Ether to attack the current PoS chain. There is 3.3 million Ether staked across over 100,000 validators, and one would need more than half of that total stake to have a chance at attacking the network, a failed attack resulting in massive slashings. This is made even harder as the attesting validators are shuffled continuously. I personally loathe the energy consumption of PoW, and believe PoS to be the future. The fact that hundreds of validators can be run on just 5 watts of power should say enough. If all validators on the current Eth2 PoS chain were run on individual machines, the energy consumption would be ≈4.4 GWh yearly vs. the current PoW chain's ≈25 TWh — a 5000-fold decrease. This is decrease is in reality probably even larger since pools, decentralized and centralized, will be running multiple validators on a single machine which affects resource usage very minimally.

hjorthjort 6y ago
> and one would need more than half of that total stake to have a chance at attacking the network Actually 1/3rd to disrupt consensus, and 2/3rds + 1 to take control of the chain like you could with a 51% attack on a PoW chain, only you'd get almost immediate and complete control over the consensus.
- throw_away_moth 6y ago
  The strength required to take control is probably 1/3 as it is with most Byzantine setups. (The 1/3 control attack against Bitcoin is selfish mining.)
  - hjorthjort 6y ago
    You can't control the network with 1/3 with BFT consensus, you need 2/3rds.
xorcist 6y ago
> really only a matter of how you ensure your chain can't be attacked The consensus mechanism serves two distinct purposes. The first is to keep global monotonic time (which is what you call "protect from attacks"). The second is as an inflation protocol. Any time you create value where there previously wasn't you have inflation. > a failed attack resulting in massive slashings That's not a good mental model for adverse actors in blockchain systems. Failed attacks are normally not published, so they won't exist unless the conditions are right.
- ryebit 6y ago
  What would a successful attack even look like? My understanding was that malicious validator has to publish votes for two different blocks in one round; which then can be used to slash them. Unlike PoW they can't "sit" on their second vote, because voters are known ahead of time, and once vote is done, opportunity is gone. They also can't choose transactions to go into block unless they're the proposer, so that's only time they can control whether attack will even benefit them. So they'll have to wait to get randomly assigned as proposer, in a committee where they control enough of the other randomly selected validators, and have pending txns at the ready to double spend (while receiving party has been sitting waiting for funds). And even then, won't that just create a fork where the minority of the validators recognize the double vote, and slash them anyways? And what users / services will stay w original fork given that proof?

by 0x64 6y ago

hjorthjort 6y ago

> and one would need more than half of that total stake to have a chance at attacking the network Actually 1/3rd to disrupt consensus, and 2/3rds + 1 to take control of the chain like you could with a 51% attack on a PoW chain, only you'd get almost immediate and complete control over the consensus.

throw_away_moth 6y ago
The strength required to take control is probably 1/3 as it is with most Byzantine setups. (The 1/3 control attack against Bitcoin is selfish mining.)
- hjorthjort 6y ago
  You can't control the network with 1/3 with BFT consensus, you need 2/3rds.

xorcist 6y ago

> really only a matter of how you ensure your chain can't be attacked The consensus mechanism serves two distinct purposes. The first is to keep global monotonic time (which is what you call "protect from attacks"). The second is as an inflation protocol. Any time you create value where there previously wasn't you have inflation. > a failed attack resulting in massive slashings That's not a good mental model for adverse actors in blockchain systems. Failed attacks are normally not published, so they won't exist unless the conditions are right.

ryebit 6y ago
What would a successful attack even look like? My understanding was that malicious validator has to publish votes for two different blocks in one round; which then can be used to slash them. Unlike PoW they can't "sit" on their second vote, because voters are known ahead of time, and once vote is done, opportunity is gone. They also can't choose transactions to go into block unless they're the proposer, so that's only time they can control whether attack will even benefit them. So they'll have to wait to get randomly assigned as proposer, in a committee where they control enough of the other randomly selected validators, and have pending txns at the ready to double spend (while receiving party has been sitting waiting for funds). And even then, won't that just create a fork where the minority of the validators recognize the double vote, and slash them anyways? And what users / services will stay w original fork given that proof?