Quote
If that's really the case, it seems to me that Chinese Bitcoin is unsustainable and what you really need is a China-specific alt coin that can run entirely within the Chinese internet.
http://sourceforge.net/p/bitcoin/mailman/message/34162353/
Topic: Hearn's Worst Case Scenario: Checkpoints in XT to "ignore the longest chain" - page 3. (Read 5232 times)
June 14, 2015, 02:20:57 PM
Hearn has a solution for all the Chinese miners stuck on the old chain, they can develop their own Chinese-specific altcoin.
http://sourceforge.net/p/bitcoin/mailman/message/34162353/
http://sourceforge.net/p/bitcoin/mailman/message/34162353/
June 13, 2015, 04:32:57 PM
This doesn't really sound good indeed... But fortunately it's the worst case scenario, and an improbable one.No miner will want things to get ruined 
Be careful about this. Anyone sitting on multiple millions of dollars worth of hardware is under threat. Miners will make the best choices for themselves in any particular scenario and that may or may not correspond to the long-term health of Bitcoin proper.
Bitcoin as a blockchain with embedded value is probably around for the duration baring some fundamental and unknown (to me) weakness in certain of the cryptography. Bitcoin as a viable method of wealth protection and transfer is subject to periods of hiatus. I'd actually be quite surprised to see it be healthy and accessible in a time of economic crisis impacting the USD. As a corollary, I'd be surprised if all of the factors used to simulate Bitcoin's natural collapse (absent a bloatfork) were equally communicated.
They are obviously under threat, that's why it's in their best interest to keep Bitcoin running smoothly and do everything for it's success... If Bitcoin is in good standing, so the miners are, I think. I'm not really seeing a situation where, for example, miners win and merchants loose. If merchants loose, miners will too in the long term, because Bitcoin will suffer... And it will suffer in price, and miners won't enjoy that, obviously
But I may be wrong. What kind of best choice for miners are you thinking in that doesn't correspond to the long term health of Bitcoin?
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June 13, 2015, 04:23:17 PM
but he is not the only person who will read and test the code. lets see what other devs say about that.
I think Hearn is the only person who decides what code is included in XT. I don't even think Gavin Andresen has commit access to XT.
June 13, 2015, 04:02:17 PM
This doesn't really sound good indeed... But fortunately it's the worst case scenario, and an improbable one.No miner will want things to get ruined
Be careful about this. Anyone sitting on multiple millions of dollars worth of hardware is under threat. Miners will make the best choices for themselves in any particular scenario and that may or may not correspond to the long-term health of Bitcoin proper.
Bitcoin as a blockchain with embedded value is probably around for the duration baring some fundamental and unknown (to me) weakness in certain of the cryptography. Bitcoin as a viable method of wealth protection and transfer is subject to periods of hiatus. I'd actually be quite surprised to see it be healthy and accessible in a time of economic crisis impacting the USD. As a corollary, I'd be surprised if all of the factors used to simulate Bitcoin's natural collapse (absent a bloatfork) were equally communicated.
June 13, 2015, 03:47:00 PM
This doesn't really sound good indeed... But fortunately it's the worst case scenario, and an improbable one.No miner will want things to get ruined
June 13, 2015, 03:37:02 PM
but he is not the only person who will read and test the code. lets see what other devs say about that.
June 13, 2015, 03:30:40 PM
The more I think about what Mike Hearn is saying in this clip, the more I'm inclined to switch sides. I was basically passively OK with 20MB, but I'm definitely not OK with a Bitcoin with centralized checkpoints. I'll be surprised if a majority of the Bitcoin community is OK with that.
Yep, increase the block size is an obvious yes. Hostile fork to achieve it? Nope. Especially not if any possibility for tragic outcomes for both forks exists at all.
(it also possibly needs some mechanism to smooth the transition to bigger blocks, and/or a target size with incentives to stay on target etc)
June 13, 2015, 03:15:50 PM
This is really disturbing. I might just forget about bitcoin for awhile.
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June 13, 2015, 03:02:04 PM
One of the most interesting take-aways is that Mike anticipates the need for continuous checkpoints. What I read into this is that he (like myself) is not anticipating a single chain as the competition but a stream of them. (The world will look morphologicaly more like a hydra than it does a slingshot.) If it were a simple 'Y' shape then a single blacklisting of a block in the 'wrong' chain would be sufficient to identify it.
Wow. I was just thinking about a simple 'Y' fork. What you're describing ... well, at least it would be interesting to watch.
The more I think about what Mike Hearn is saying in this clip, the more I'm inclined to switch sides. I was basically passively OK with 20MB, but I'm definitely not OK with a Bitcoin with centralized checkpoints. I'll be surprised if a majority of the Bitcoin community is OK with that.
June 13, 2015, 02:24:56 PM
Jeez I'm glad to see at least one person paying some attention.
I would have thought that at this point Hearn's best strategy would be to bluster over this issue. Perhaps he felt constrained by some of the interviews with the miners.
The idea of how to subvert the 'longest chain' is not new. It would be needed in some cases to overcome a 51% attack, and more recently in the context of a fork war which is basically the same principle. A guy who wins control of the MultiBitch client fleet has a leg-up on his competition, and I've for years felt that this was the driving force behind developing such a fleet.
In my own musings about the problem, I assumed that the chain I favored would not be the longest. Mike's admission that he may have the same problem is very heartening since it means that my favored chain might actually not have it!
One of the most interesting take-aways is that Mike anticipates the need for continuous checkpoints. What I read into this is that he (like myself) is not anticipating a single chain as the competition but a stream of them. (The world will look morphologicaly more like a hydra than it does a slingshot.) If it were a simple 'Y' shape then a single blacklisting of a block in the 'wrong' chain would be sufficient to identify it.
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June 13, 2015, 01:57:46 PM
There was part of the discussion with Mike Hearn on Epicenter Bitcoin last week that I haven't seen discussed. I cut out the relevant 2 or 3 minutes:
https://youtu.be/DB9goUDBAR0
Here is part of what he said:
I keep reading that the fork wouldn't take place until "90%" of nodes and/or miners have upgraded, but that doesn't sound like what Hearn is describing at all.
I'm not against lifting the hard block size limit from 1MB to 20MB (or some compromise like 8MB), but trying to do it without the miners in China sounds like a disaster. I'm strongly against putting checkpoints into the code to "ignore the longest chain." It's scary to think the idea even sounds reasonable.
https://youtu.be/DB9goUDBAR0
Here is part of what he said:
Quote
Do we really have the majority we think we do? ... There's nothing like measuring it for real. The worst case scenario is the majority ... the economic majority ... is in favor but the hash power, the mining majority is not. That would be a very messy situation for bitcoin.
There've been concerns raised by mining pools in China where a lot of mining has been going on that their connectivity has been extremely poor compared to the rest of the internet for a bunch of reasons. If the needs of the wider global bitcoin community start diverging from what miners in China want, then who wins? The answer is the economic majority wins, right, the wider community wins, but it would require a bit of a technical mess to sort everything out in that case.
... If we imagine this kind of worst case scenario happening, they would ignore the longest chain. Doesn't matter that it's the longest if it's ... um ... uh ... you know ... well, let me rephrase that.
... If miners were building a longer chain than the 20 Meg chain, then the client would keep switching back to it and keep ending up with this bigger and bigger backlog. At that point what we would have to do is like checkpoint blocks into both the full nodes and the SPV wallets. So that's a much larger and more complicated upgrade to force it onto the "larger" chain, right.
In the worst case scenario if the miners and the rest of the bitcoin community end up in some kind of full-fledged war, that would basically wreck bitcoin.
There've been concerns raised by mining pools in China where a lot of mining has been going on that their connectivity has been extremely poor compared to the rest of the internet for a bunch of reasons. If the needs of the wider global bitcoin community start diverging from what miners in China want, then who wins? The answer is the economic majority wins, right, the wider community wins, but it would require a bit of a technical mess to sort everything out in that case.
... If we imagine this kind of worst case scenario happening, they would ignore the longest chain. Doesn't matter that it's the longest if it's ... um ... uh ... you know ... well, let me rephrase that.
... If miners were building a longer chain than the 20 Meg chain, then the client would keep switching back to it and keep ending up with this bigger and bigger backlog. At that point what we would have to do is like checkpoint blocks into both the full nodes and the SPV wallets. So that's a much larger and more complicated upgrade to force it onto the "larger" chain, right.
In the worst case scenario if the miners and the rest of the bitcoin community end up in some kind of full-fledged war, that would basically wreck bitcoin.
I keep reading that the fork wouldn't take place until "90%" of nodes and/or miners have upgraded, but that doesn't sound like what Hearn is describing at all.
I'm not against lifting the hard block size limit from 1MB to 20MB (or some compromise like 8MB), but trying to do it without the miners in China sounds like a disaster. I'm strongly against putting checkpoints into the code to "ignore the longest chain." It's scary to think the idea even sounds reasonable.
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