Ethereum Proof-of-Stake • Hacker News Board

Re: Ethereum Proof-of-Stake

#211

Post by olalonde » Thu, Jul 07, 2022, 3:55 PM UTC

webinvest wrote: post #206

olalonde wrote: post #116

Earlier quoted context omitted.

> Then the US government smash down your door and throw you in federal prison because you're actively working to help North Korea. Not a real issue because transactions are not associated with IPs. There's basically no way to know the country of a sender or recipient. Also, it was ruled that virtual currency miners are not subject to AML regulations[0]. [0] https://www.fincen.gov/sites/default/files/news_release/2014…

Not related to miners but to the best of my knowledge, every transaction is broadcasted to the network from an IP address. Therefore the IP can be traced back or hidden with TOR or proxies. Receiving cryptocurrency is by default anonymous because it requires no public action on the part of the receiver. Except, checking a transaction tx or wallet balance on blockchain.info could flag the IP checking that balance.

> Not related to miners but to the best of my knowledge, every transaction is broadcasted to the network from an IP address.

Right, but even if you banned North Korea IPs, you'd still get their transactions through the transaction relay mechanism (other peers outside North Korea relaying their transactions).

Re: Ethereum Proof-of-Stake

#212

Post by codechicago277 » Thu, Jul 07, 2022, 3:56 PM UTC

Barrera wrote: post #64

The article does not even mention long range attacks in which large portions of the block chain are rewritten. This is made extremely hard in Bitcoin through proof-of-work. To rewrite history you must re-do all of the work, which means you burn enough real-world energy to work faster than the entire rest of the network (aka majority hash rate attack). It's allowed, but expensive. In PoS, there was never any work, so…

That you’re getting downvoted speaks to the poor quality of discussion on this thread. To me this is the core issue with PoS. I don’t know enough about it to say if the Ethereum devs have solved it or not, but this is a much more interesting topic than misguided comparisons of PoS to crony capitalism, which is just uninformed.

Re: Ethereum Proof-of-Stake

#213

Post by camjohnson26 » Thu, Jul 07, 2022, 4:03 PM UTC

0xfoobar wrote: post #165

Barrera wrote: post #64

The article does not even mention long range attacks in which large portions of the block chain are rewritten. This is made extremely hard in Bitcoin through proof-of-work. To rewrite history you must re-do all of the work, which means you burn enough real-world energy to work faster than the entire rest of the network (aka majority hash rate attack). It's allowed, but expensive. In PoS, there was never any work, so…

Article author here. Supermajority attestations and block finalization, as well as withdrawal queues, prevent long-range attacks. To attempt to reorg a finalized block (blocks are generally finalized after 6 minutes) you have to commit to losing 1/3 of total staked ether, currently several billion dollars. The only participants who can equivocate (vote for two blocks at the same height) are active validators so there…

Theoretically, if somebody forked the Ethereum PoS blockchain and faked timestamps to catch up to the real chain’s height, would there be any way to know which was the original other than community agreement? Seems like PoW makes it impossible since duplicating the original chain is prohibitively expensive.

Not challenging the solution, just genuinely curious in how PoS works.

Re: Ethereum Proof-of-Stake

#214

Post by amluto » Thu, Jul 07, 2022, 4:04 PM UTC

redox99 wrote: post #182

amluto wrote: post #156

Following some links: https://notes.ethereum.org/@vbuterin/single_slot_finality > If 51% of validators start censoring, the victims and users can coordinate on a minority soft fork where they build on each other’s blocks and ignore the attacker. On the minority soft fork, the attacker’s deposits would lose millions of ETH to an inactivity leak, and after a few weeks the chain resumes finalizing. It seems that this co…

That's the social consensus, or "L0 consensus". It's a fork, so on only on this fork the attackers would lose the ETH. The social consensus means that actual humans, in front of these 2 forks of ETH , the original chain being attacked, and the one where all the attackers stake has been deleted so it's safe (and also non-attackers "richer"), humans would call the latter "Ethereum" and use that. And the former would fa…

Does that really work?

Suppose I stake enough ETH to create a fork that passes muster (which may include quite a bit of inactivity penalties for the honest folks, etc). Then I validate honestly, withdraw my stake, and launder those ETH for different ETH.

Now I make my anachronistic fork. I use those same private keys, invent inactivity penalties for everyone else, etc.

This fork is of dubious value. If I publicize it, anyone can prove that cheating happened, although I can’t actually be slashed because, on the real chain, I’ve already withdrawn and, on my chain, I won’t slash myself. Anyone who looks at (centralized!) websites will know my chain is fake. Anyone who sees both chains will clearly know that funny business happened.

But perhaps I can fool a node that was simply offline during the attack. As far as a regular node is concerned, both chains are a bit funny — slashable votes occurred. But I can probably fudge my chain so it wins over the real chain, and I can potentially attack my victim node.

The best part of this attack is that it cost essentially nothing. The computing resources I used are negligible. I spent 0 ETH, although I needed access to some private keys that required having money at some point to obtain.

At least with PoW, I need a lot of hashing to do this.

Sure, the L0 consensus means I’m unlikely to be able to double-withdraw $10bn from a pair of exchanges, but that’s a pretty weak argument for using Ethereum over a centralized system.

Re: Ethereum Proof-of-Stake

#215

Post by dqpb » Thu, Jul 07, 2022, 4:06 PM UTC

haarts wrote: post #66

bibabaloo wrote: post #46

Earlier quoted context omitted.

> the more you have of the capital the more you influence the system That's not how PoS works, though?

How does it work?

Silvio Micali (MIT professor and Turing award winner) describes a PoS implementation which addresses all the concerns in this thread:

https://youtu.be/NykZ-ZSKkxM

Re: Ethereum Proof-of-Stake

#216

Post by olalonde » Thu, Jul 07, 2022, 4:09 PM UTC

WJW wrote: post #201

olalonde wrote: post #139

Earlier quoted context omitted.

It was actually ruled in 2014 that virtual currency miners are not money transmitters[0]. [0] https://www.fincen.gov/sites/default/files/news_release/2014...

From the link you posted: > The first ruling states that, to the extent a user creates or “mines” a > convertible virtual currency solely for a user’s own purposes, the user > is not a money transmitter under the BSA. That seems to leave rather a lot of open space IMO. For example, does a POS validator create convertible virtual currency? Clearly. But is it solely for their own purposes? Do they become a money transm…

It probably seems unclear to you because you are not familiar with the industry and/or AML regulations. To answer your questions, cryptocurrency miners are not money transmitters, even if they sell their cryptocurrency and they can accept fees from any transactions.

Of course regulations can change, but in this case it seems unlikely unless the intention is to effectively "ban" cryptocurrency.

Re: Ethereum Proof-of-Stake

#217

Post by [deleted] » Thu, Jul 07, 2022, 4:10 PM UTC

syzygyhack wrote: post #82

drdrek wrote: post #31

Ahh proof of stake, the nail in the coffin of decentralization. What did you say? the more you have of the capital the more you influence the system? what a novel concept! Monterey and legal systems based on structures that are at least partially built to take care of the needs of people of similar culture and geographic area? YUCK! Machine enforced plutocratic system where early adopters and syndicates have absolute…

The decentralization of PoS depends entirely on initial token distribution.

[deleted]

Re: Ethereum Proof-of-Stake

#218

Post by 0xfoobar » Thu, Jul 07, 2022, 4:11 PM UTC

camjohnson26 wrote: post #213

0xfoobar wrote: post #165

Earlier quoted context omitted.

Article author here. Supermajority attestations and block finalization, as well as withdrawal queues, prevent long-range attacks. To attempt to reorg a finalized block (blocks are generally finalized after 6 minutes) you have to commit to losing 1/3 of total staked ether, currently several billion dollars. The only participants who can equivocate (vote for two blocks at the same height) are active validators so there…

Theoretically, if somebody forked the Ethereum PoS blockchain and faked timestamps to catch up to the real chain’s height, would there be any way to know which was the original other than community agreement? Seems like PoW makes it impossible since duplicating the original chain is prohibitively expensive. Not challenging the solution, just genuinely curious in how PoS works.

Great question, it's not timestamps but attestations (signed validator votes for pairs of checkpoint blocks) that determines the canonical chain head. This fork choice rule, known as LMD-GHOST, is different from PoW which has a "greatest difficulty" rule for determining the canonical chain.

There is some element of bootstrapping who the original validator set was, known as "weak subjectivity". There's a great post from Vitalik exploring this further at https://blog.ethereum.org/2014/11/25/proof-stake-learned-lov...

Re: Ethereum Proof-of-Stake

#219

Post by aeternum » Thu, Jul 07, 2022, 4:16 PM UTC

cowtools wrote: post #170

rglullis wrote: post #136

Earlier quoted context omitted.

"By large enough", you mean 67% to attempt to do it with some chance of success, and if it fails it gets slashed. Not to mention that no one would be interested in using any network where this level of centralization could pose a real threat, and the most likely outcome of such a scenario would be a loss of the value of the native token.

...but if it succeeds, then everyone else gets slashed. The network has no concept of "truth". PoS doesn't fix this, it just puts all your eggs in one basket. Who would be interested in using any network which exists only for the profit of the existing stakeholders? Why not just fork it?

Forking it is the real threat. If some entity does end up controlling 67% or doing something the community does not agree with, people will just stop using the chain.

This already happened once with Ethereum.

Re: Ethereum Proof-of-Stake

#220

Post by k2xl » Thu, Jul 07, 2022, 4:16 PM UTC

> To attempt to reorg a finalized block (blocks are generally finalized after 6 minutes) you have to commit to losing 1/3 of total staked ether, currently several billion dollars.

Hmm... Several billion dollars is not actually that much money for nation states. Am I misunderstanding something here? Shouldn't it be much more expensive than several billion?