> In other words, a person using ethereum's POS will need to turn on their computer once every 4-6 months to sync to the network
That only works if you were already bootstrapped to the network. But if this is your first time joining the network, how can you tell?
Weak subjectivity more or less becomes a proxy for letting the major players decide. If your friend says that they've been on the chain for years and chain 'X' is the true chain, but blockchain.info is saying that chain 'Y' is the true chain, what happens? How can you tell if both seem valid? If a Proof-of-Stake system had an NYA-style agreement to perform a hardfork that benefits major players over individuals, would you be able to fight it?
I think it would be much harder in a Proof-of-Stake system than in a PoW system, because in PoW creating an alternate system costs hundreds of millions of dollars in electricity.
> an attacker's addresses will be known and the protocol will slash their funds for most types of attack
This only works if you can get a transaction through to prove on-chain that the attacker has been double signing. If you can't (which you won't be able to because the attacker has control), you can't slash their funds.
> If there was a successful 51% attack against bitcoin, the hashrate would drop precipitously
The hardware doesn't magically stop existing. It may turn off, but many miners have contracts with electrical companies that require them to use the electricity. But even with that aside, the hardware would merely turn off. Buy some more hardware, and then you can coordinate with the existing honest hardware to resume mining, now outnumbering the 51% attacker.
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Another issue with PoS systems: they traditionally have very low participation rates. A 51% attack in a PoS system is often more like a 10% attack, because only 20% of the people are actually staking their coins anyway.
In a market as volatile as modern cryptocurrency (remains to be seen if volatility would drop), it's very expensive to stake your coins for 6 months in a row because that means you can't be doing any trading on those coins, or deploying them as any other form of capital.
All good counterpoints- Actually, I mostly agree with all of these points and they portray the issues in a fair way, so I won't comment any more and let readers come to their own conclusions which side has the strongest argument.
That only works if you were already bootstrapped to the network. But if this is your first time joining the network, how can you tell?
Weak subjectivity more or less becomes a proxy for letting the major players decide. If your friend says that they've been on the chain for years and chain 'X' is the true chain, but blockchain.info is saying that chain 'Y' is the true chain, what happens? How can you tell if both seem valid? If a Proof-of-Stake system had an NYA-style agreement to perform a hardfork that benefits major players over individuals, would you be able to fight it?
I think it would be much harder in a Proof-of-Stake system than in a PoW system, because in PoW creating an alternate system costs hundreds of millions of dollars in electricity.
> an attacker's addresses will be known and the protocol will slash their funds for most types of attack
This only works if you can get a transaction through to prove on-chain that the attacker has been double signing. If you can't (which you won't be able to because the attacker has control), you can't slash their funds.
> If there was a successful 51% attack against bitcoin, the hashrate would drop precipitously
The hardware doesn't magically stop existing. It may turn off, but many miners have contracts with electrical companies that require them to use the electricity. But even with that aside, the hardware would merely turn off. Buy some more hardware, and then you can coordinate with the existing honest hardware to resume mining, now outnumbering the 51% attacker.
------------------
Another issue with PoS systems: they traditionally have very low participation rates. A 51% attack in a PoS system is often more like a 10% attack, because only 20% of the people are actually staking their coins anyway.
In a market as volatile as modern cryptocurrency (remains to be seen if volatility would drop), it's very expensive to stake your coins for 6 months in a row because that means you can't be doing any trading on those coins, or deploying them as any other form of capital.