Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Mainnet Merge Announcement

blog.ethereum.org

Post reply on HN
Print view View original

601–609 of 609 posts

Re: Mainnet Merge Announcement

#601

Post by 3np »

proto-n wrote: post #183
tboyd47 wrote: post #152

Earlier quoted context omitted.

That assumes the other 49% won't accept the bad guys' blocks in their chain. Those blocks are valid, so the 49% will accept them and build off of them. At any point there is still a 49% chance the next block will be mined by a good guy. If the bad guys decide not to accept the good guys' blocks, then they are hard forking Bitcoin and will end up just like Bitcoin Cash: irrelevant. This is the exact problem PoW was de…

They are not hard-forking, it will be compatible with the original chain and original rules. There will be two competing forks, one censored, one not censored, and the censored one is longer (because 51%). Consensus rules say longer chain is valid. So it _is_ the official "bitcoin", according to consensus rules. The 51% attack is not some made up thing.

> Consensus rules say longer chain is valid.

I will not go into depth here but it's a commonly held view that this changes under PoS. Just flying by so hopefully sources are easily located

Re: Mainnet Merge Announcement

#602

Post by 3np »

cesarb wrote: post #308
tboyd47 wrote: post #270

Earlier quoted context omitted.

So, now that I've obliterated the 51% attack idea, shall we move on to 66% attack? It doesn't matter if it's a 90% attack. The minority miners are constantly receiving and using the majority's blocks. So it is not 66% vs. 33%, or 90% vs. 10%; it is 60% vs. 100% and 90% vs. 100%. All it takes is for the less-restrictive minority to mine two blocks in a row and they've permanently outpaced the majority's more restricti…

> The minority miners are constantly receiving and using the majority's blocks. They can use the majority blocks at the cost of discarding their earlier blocks . Every time they accept a block from the majority, they undo all the work they had done earlier. > All it takes is for the less-restrictive minority to mine two blocks in a row and they've permanently outpaced the majority's more restrictive chain. All it tak…

All it takes then is for the majority to mine three blocks in a row at the precise right moment, consistently enough that there is lower gas available in minority blocks than demand from sanctioned transactions.

If that's what it comes down to (and there is reason to believe it won't), I imagine sanction addresses will still transact, just with higher latency and at higher cost than others.

Re: Mainnet Merge Announcement

#603

Post by gus_massa »

tboyd47 wrote: post #593
gus_massa wrote: post #499

Earlier quoted context omitted.

They are not block, they are chained blocks. Oversimplifiying, each block has 3 parts: 1) The hash of the old block. 2) The new transactions. 3) A number that must be bruteforced until you get a hash of all the block with a lot of zeros. If you try to copy one block in the other chain/fork, then the hash of the previos block is invalid. If you change just that part of the block, you must bruteforce a new number until…

I want to thank everyone who engaged with me instead of downvoting me. Okay, I think I see now where I was separately wrong and partially wrong in the previous comments. When I said there's a huge monetary upside to a 51% attack, that's wrong. There's not really any upside to speak of, especially considering the huge amount of computing resources you would need to do it. So it's not surprising it hasn't been tried ye…

In your scenario, you are using

  66% ..3..........2....1.3.....................2......2.X
  33% ..3..........2....1........1...1...................X
but that's closer to a 50%-50% split of the miners, not a 66%-33%.

The problem is that 2 and 3 will produce the double of blocks. For e while 1 may tie or get ahead, but after 30 blocks the the 23 fork will almost always be like 10 blocks ahead of the only 1 fork.

Ignoring most of the . to make the graph shorter

  66% 3213...223.3223..23.23.323..3.2223
  33% 321.11....1....11..1..1...11.1....
or looking at each chain

  66% 32132233223232332332223
  33% 3211111111111
After a while, 1 can

A) Give up and start mining censored blocks

B) Start a new fork, from the current 2-3 chain with many censored blocks

C) Declare that they are a fork and convince the exchanges to give them a new moniker, like ETC of BXC

D) Convince the exchanges that they are the real chain in spite they are shorter, and convince the exchanges to give the other chain a new moniker.

Re: Mainnet Merge Announcement

#604

Post by gus_massa »

3np wrote: post #602
cesarb wrote: post #308

Earlier quoted context omitted.

> The minority miners are constantly receiving and using the majority's blocks. They can use the majority blocks at the cost of discarding their earlier blocks . Every time they accept a block from the majority, they undo all the work they had done earlier. > All it takes is for the less-restrictive minority to mine two blocks in a row and they've permanently outpaced the majority's more restrictive chain. All it tak…

All it takes then is for the majority to mine three blocks in a row at the precise right moment, consistently enough that there is lower gas available in minority blocks than demand from sanctioned transactions . If that's what it comes down to (and there is reason to believe it won't), I imagine sanction addresses will still transact, just with higher latency and at higher cost than others.

The blocks with the "sactioned" transactions will be ignored by most of the people, so they will only live in forks that everyone will ignore.

Assuming enough hash rate and the exchanges (and the users) agree to ignore the "sactioned" transactions, then they will never be in the main chain, not even slowly.

Re: Mainnet Merge Announcement

#605

Post by 3np »

gus_massa wrote: post #604
3np wrote: post #602

Earlier quoted context omitted.

All it takes then is for the majority to mine three blocks in a row at the precise right moment, consistently enough that there is lower gas available in minority blocks than demand from sanctioned transactions . If that's what it comes down to (and there is reason to believe it won't), I imagine sanction addresses will still transact, just with higher latency and at higher cost than others.

The blocks with the "sactioned" transactions will be ignored by most of the people, so they will only live in forks that everyone will ignore. Assuming enough hash rate and the exchanges (and the users) agree to ignore the "sactioned" transactions, then they will never be in the main chain, not even slowly.

Which one is the "main" chain is entirely/ subjective. If users prefer the unsanctioned chain, it can very well be "main", regardless (see BCH/BSV debacle on "who's the real BTC", also ETC).

Also just noting that while the conversation here is about Ethereum, you are describing the fork rules of Bitcoin. Next month the concept "hash rate" won't exist on ETH mainnet (potentially depending on who you ask; looks like there might be an ETC2).

Re: Mainnet Merge Announcement

#606

Post by TheDudeMan »

josu wrote: post #488
hn_throwaway_99 wrote: post #330

Earlier quoted context omitted.

It's also fundamentally limits the growth potential of BTC. In a PoW system, the amount of work done must be proportional to the total value of all BTC (if not, it would make 51% attacks feasible). So if BTC uses an Argentina's worth of energy now, if the value of BTC grew 10X it would have to use on the order of 10 Argentina's worth of electricity. Obviously, that is not sustainable, and it ensures BTC can never gro…

If the hashrate can't keep up with the price increase because it has exhausted all sources of available electricity, then difficulty will adjust down. This doesn't limit the potential growth of Bitcoin, it only puts an upper bound on the security per block.

lmao, this would be apocalyptic.

Re: Mainnet Merge Announcement

#607

Post by TheDudeMan »

TheDudeMan wrote: post #345
hn_throwaway_99 wrote: post #330

Earlier quoted context omitted.

It's also fundamentally limits the growth potential of BTC. In a PoW system, the amount of work done must be proportional to the total value of all BTC (if not, it would make 51% attacks feasible). So if BTC uses an Argentina's worth of energy now, if the value of BTC grew 10X it would have to use on the order of 10 Argentina's worth of electricity. Obviously, that is not sustainable, and it ensures BTC can never gro…

Have you seen a graph of global energy use over time? It goes up.

Now I see that "throwaway" probably didn't mean "the amount of work done" but instead "the amount of money spent on work done".

Re: Mainnet Merge Announcement

#609

Post by jimmydorry »

simiones wrote: post #360
jimmydorry wrote: post #292

Earlier quoted context omitted.

It would depend on how close the attack is to 51/49%. If it's close, the 49% chain should be able to keep ahead, making the attack take a long time and thus be very expensive... but there would be constant block reorganisations. The 51% chain is mined with 51% of the total mining power, while the 49% chain will contain 100% of the mining power (as the 49% miners are more than happy to build off the 51% chain, while t…

Any block you are working on has a reference to the latest block in the network. So, every miner starts from scratch once a new block is added - the 49% pool doesn't have any advantage compared to the 51% pool. Each miner takes a bunch of transactions and chooses a previous block B1 to build on, then starts hashing. If some other minerB advertises a new block B2 based on B1 that includes different transactions before…

Except, that minerA can't build off block B1 because it has transactions in it that it doesn't agree with. minerB just has to keep trying to find blocks to put the censored transactions into, while minerA is fighting against the rest of the miners to outpace them. This only really becomes possible at much higher thresholds, e.g. 70/30. Meanwhile, the community will see what is happening and steps may be taken to either soft-fork or hard-fork the bad actors off the network.
Post reply on HN