Bitcoin Forum

https://medium.com/@vcorem/lesson-learned-from-the-classic-coup-attempt-or-why-core-needs-to-prepare-a-gpu-only-pow-6a9afe18e4b0

So, as I write these words, it seems that Classic has a good chance of meeting its activation Threshold. Jonathan is aiming for Classic to be activated when 75% of the last 2,016 (currently coded 1,000 but he said in the interview that he might increase to 2,016) mined blocks indicate support of the Classic fork, meaning the miners that mined them are ready to do a 2MB Hard Fork and leave behind everyone on Core.
What will happen to Core chain if Classic will be activated?

Will Classic activation mean the end to the Core chain ?
Not necessarily; Careful planning on behalf of Core will allow it survive.

I believe that Core developers will split into three camps: Some will join Classic Chain (and fork), some will quit Bitcoin altogether, and some will continue development on Core Chain (and fork).

I tend to believe that most Core developers will remain and implement the Core scalability road-map as planned. I simply don’t see Core following Classic’s governance model in which the users vote on issues.

Mainly, Core needs to replace its PoW function, preferably to a function which make any effort to create ASIC for it economically nonviable. I’ll discuss such a proposal below.
The other thing Core needs to do is to change the Transaction ID, in order to create a complete split of coins.

By implementing the above, upon Classic activation, each Bitcoin will be split to ClassicCoin and CoreCoin. Each coin will be transact-able separately and will have a different market value. Most of the exchanges will probably support both Chains, hence each Coin will have different market value based on supply and demand.

From the user perspective, she will needs to install both wallets (Core and Classic) and import the old private key into both wallets. It makes sense that multi chains wallets will be created, so the user will be able to transact easily with wallets on both Coins. These wallets may even present the following arithmetic: 1 CoreCoin + 1 ClassicCoin = 1 BTC, so if you have 80 CoreCoins and 73 ClassicCoins it would show up as 73 BTC + 7 CoreCoins. It might be able to transact in that way as well, sending CoreCoins and ClassicCoins with one wallet “Send” action to the receiver.

....


Suggestion for GPU only PoW change for Core

In order to survive, Core needs to change its PoW or else Core miners won’t be able to mine at all or Core chain will be susceptible to 51% attacks from Classic miners. I purpose the following, in order to prevent mining centralization, and prevent the possibility of such a governance coup in the future:

    Core will prepare a large set of cryptographic hash functions, at least 100 or more initially. Any simple (not memory hard) function will do

    Every 3 months (12,096 blocks), the PoW change automatically, by random data hashed from the last block before the change

    A selection of 10 or more functions is made from the large set, selected deterministically from last block data

    If the functions have tunable parameters and or constants then those are also selected deterministically from the last block data

    Those 10 or more functions are constructed in a stack (e.g. X11)

    The Stack of functions with their new constants and parameters (all selected deterministically by hashing last block data) is the NewPoW

    In order to prevent Hash-Rate oscillation (very bad…), The OldPoW and the NewPoW coexist for one month (4,032 blocks)

    Each PoW function actually serves for 5 months:

    - One month of Phase In period in which it co-exists with it’s predecessor

    - Three months in which it serves alone as the only PoW

    - One month of Phase Out period in which it co-exists with it’s successor

    During the Phase In period, the NewPoW difficulty is set initially to a very low value, to incentivize miners to mine it.

    However, During the first 252 blocks (1/16 of the phase in period), only one block with the NewPoW is allowed every 16 blocks. If more then one block with the NewPoW is mined during this period, the rest will be discarded.

    There will be a lot of miners trying to mine the new PoW since its difficulty was set to a low value, there will be a lot of soft forks. To avoid it, the block with NewPoW with minimum BlockHash is accepted as the winner, all the rest are discarded.

    In the next 252 blocks (second 1/16 of the phase in period), only two blocks with the NewPoW are allowed every 16 blocks.

    Every subsequent 252 blocks of the phase-in period, one more block with NewPoW will be allowed.

    After each 252 blocks of the phase-in period, the difficulty of the NewPoW will be adjusted based on the time it took to create blocks with NewPoW from the beginning of each 16 blocks period.

    By the end of the phase-in period, the OldPoW will be retired and the only acceptable blocks will be blocks with the NewPoW


This proposal if implemented correctly, will bring a never ending GPU mining on Core chain. It will also reduce the hash-rate oscillation between each PoW change. In order to make sure an ASIC effort will be uneconomic, the initial set of functions needs to be large enough. In addition, on every future Hard Fork of Core Chain, additional hash functions need to be added to this set (assuming CoreCoin price increase).

....

Thanks goes to:

    Adlai Chandrasekhar for suggesting the automatic method of replacing PoW parameters using Blockchain data
    Benny Gorlick for suggesting to select the next PoW from a large set of predefined functions
    Emin Gün Sirer for suggesting the mechanism to prevent hash-rate oscillation after each PoW change
    James Hilliard for creating a tool that generates a transcript from the WeChat group “MinerInWorld”
    Vitalik Buterin for reviewing the proposal
    Luke-Jr for reviewing the proposal

Seems to me that GPU mining is centralisation in one form. Ideally, you want a branching-hard PoW which cannot easily be ported to GPU (or baked into an ASIC) with any performance increase over plain CPU.

wonderful changes ,looking forward for that, i liked to concept of GPU mining ,which everyone can participate rather than big mongers who owns huge number of ASICS  ;)

10 stacked hash functions, randomized from a set of 100? Rotated every 3 months? Lol plan delivers



And the most well motivated to come up with algorithmic shortcuts (==moreMiningBTC) for the latest hash-stack monster will always be the most deserving; young, bright, hungry and
with loads of time to spare (day-to-day and long term). The Blockchain "Alliance" can stick that in their respective crackpipes.

I'm not sold on super-complex functions with Byzantine rules (despite the fact when I tried to write one, it looked a lot like what Guy came up with)!   :D

More complexity just raises the barrier to entry for ASIC manufacturers, exacerbating the centralization we already see with fairly simple SHA-256.  Not that working at 16nm is simple...but still, buying proprietary IP for up to all 100 isn't going to be cheap!   :(

Since we can't defeat all ASICs, perhaps we should try to encourage as much competition as possible and KISS.

And even with ASIC designs for all 100 algorithms, they still can't outcompete thousands (or possibly even hundreds of thousands next wave) of GPUs and FPGAs, and certainly cannot be as quickly up-and-hashing. And what then happens when 100 becomes 101?  :D


Not convinced about that logic when current ASIC overlords are trying to act like they have a gun to Core's head, but we'll see to what extent the credibility of their threat unravels soon enough.

I don't understand. Whatever the algorithms are, there will always be specialized chips made with enough time. If a change allows regular GPU mining for now, I'm sure it won't be long until specialized GPU's that maximize mining efficiency will come out.

Mining cost is the baseline of coin value, if you change to GPU mining, coins value will drop to single digits thus abandoned by investors, better use litecoin in that case

I think you have it backwards.  The cost of mining does not define the value of the coin. The amount of money people will be willing to pour into mining the coin is, however, determined by the value of the coin.

Is that your case for "why bitcoin will appreciate forever", Jonny? In any case, your assertion doesn't withstand a basic reality test: if it were true, it's conceivable that mining costs would be way, way higher than at present. Seeing as it would provoke a 3rd (4th?) mining gold rush.

https://coin.dance/nodes


there's hardly any nodes running classic.. what do you mean it has a good chance?

The increasing number of people smoking some bad juju and coming up with this pipe-dream shit astounds me.

This is a nice website you submitted us. I think that it should be the nodes + the miners that should be able to decide to fork or not, not only the miners.

oh i see now, there are no intentions in Classic to change the algo, it is strictly about block size increase from 1mb to 2mb.. OP was misleading..

Are you talking about XT/Classic style contentious hard forks, having a backup plan to change the PoW if necessary, both, or neither?

Do you know arbitraging? This has been discussed for years in the economy forum, I thought it is already a basic knowledge, just search for it there

Put it simply, if it cost $1 to mine one bitcoin and the market price is $400, everyone will mine and immediately sell, no one will buy; and those who want to hold coin will immediately sell their coins and mine it back at a much lower cost. That is $399 profit for every $1 spent, 399x return on investment. No matter how large the market demand is, the arbitraging will make sure the price keep dropping until it reaches the current mining cost

So, unless the mining cost quickly rise up to $400 overnight, a new pow coin with neglectable initial mining cost will just crash to zero in a very short time

Change PoW.

Contentious is not the same as absurd.

Note this is not a vote for anything in particular and should not be taken as such.

You are assuming no real demand for bitcoin except speculation, which I expect will not be the case forever.  If there is real demand, the demand will drive the price, and the cost of mining will rise to the value set by demand - not the other way around.  If, on the other hand, demand remains purely speculative, then you would probably be correct that the price will fall to the floor established by the mining cost.

That will be the case, the mining cost should always be close to bitcoin's market price, otherwise arbitraging will happen to make them equal

Due to that the block reward are less and less, you might be able to maintain the same cost while have price double every 4 years, in case block space are always plenty thus the fee income is always a small part of the block reward

Of course there is market demand, but if I need one bitcoin, and it takes $1 to mine but $400 to buy, should I mine or buy? Maybe I don't have the necessary tools to mine, but I'm quite sure there will be plenty of miners who are willing to sell to me at $10, which already bring them a 1000% profit immediately

Maybe there are many people who are so stupid that they blindly buy at $400 a coin because they don't know the PoW has changed. But if there is only one guy knows this, he will immediately borrow as much coin as possible and at the same time buy as much hash power as possible, and dump the coin on exchange and mine them back, and in a few days everyone knows how to get rich quick

I understand what you are saying...  I'm just trying to clarify that the price is not defined only by the cost of mining.  The cost of mining sets a floor for the price, and demand can potentially pull the price to any level at all above that floor - and the price of mining will be pulled up at the same time, as it will be profitable (and ultimately necessary) for miners to spend more money to mine, no matter what the mining mechanism is (CPU, GPU, ASIC, whatever).

Usually the serious demand always first go to mining, since that is the lowest cost and will give them freshly mined coins. Only in case there is a sure anticipation of huge jump in difficulty due to new mining technology, they will go to exchange

If you have so serious problem inside bitcoin that you even need to change PoW, the chance that the demand would still rise around the fork period is almost 0

IMO, changing the PoW is not something to be done except as a last resort to protect the blockchain from a ~51% attacker.

But in a doomsday scenario, with an ongoing contentious hard fork causing unacceptable risk of catastrophic consensus failure, I'd appreciate having some good 2nd strike options having been presciently filed away on the shelf for future consideration in exigent circumstances.

It's like having a fire hose behind glass.  Not a good idea to play with most of the time, but if there's a fire then it's time to break the glass and deploy emergency countermeasures.

In your opinion, is Bitcoin married to SHA-256 like it's married to other control variables like the 21e6 coin emission schedule, 10 minute block target, and 1MB blocks?

Is there a better way to resolve a (messy, scary, dangerous, mutually destructive) fork war than by one of the chains moving to another PoW?

I don't see Bitcoin as being defined by SHA-256; IMO the particular PoW (while carefully chosen as the best fit for the job) isn't an intrinsic feature of the Nakamoto Consensus protocol.

Is there something special about SHA-256 that other functions cannot do as well or better?

That's cute, equating limiting to 1MB blocks to being married to sha256. Don't try and take my one line comment as the opener for something completely unrelated on a completely different scale. This thread is about changing PoW, and I said clearly contentious is not the same as absurd.

Well of course changing PoW in anything but the most dire circumstances would be "absurd."  But that is the SHTF scenario a ToominCoin 51% attack forces us to confront.  So let's hope for the best while we plan for the worst.

Are you saying sha256 is a 'less arbitrary/more intrinsic' feature of Bitcoin than 1MB blocks?

I have no problem sacrificing sha256 in order to preserve 1MB blocks, unless you can demonstrate PoW change is more of a threat to our diverse/diffuse/defensible/resilient network than >1MB (2MB or whatever) blocks.

It seems you have reached the opposite conclusion, and say that 1MB blocks may be sacrificed in order to preserve sha256.

Is that correct, or was something lost in my translation from the Australian?   :P

Characterizing Guy Corem & Co's POV as "absurd" only tells the rest of us you disagree with it, while leaving your audience wondering what your exact points of contention are.

Changing the proof of work that secures the system from hundreds of millions of dollars worth of mining hardware (whatever you make of the degree of centralisation) for a multi-billion dollar economy into one that will start again from scratch in the hands of a few thousands of dollars worth of GPUs at peoples' homes is as disruptive as increasing the block size?

It's a shame that you make me spell it out like this, clearly baiting me. I get sick of these discussions very quickly for that exact reason. I'll go hide in my mining corner while everyone continues their endless debate on that note.

Well, this is the third time in this thread that you've made a very arrogant assertion of fact, in the actual expectation that the audience simply accept what you say due to your erudition. Not the case. It's possible you have a really good reason to make your statements, but no-one except you knows what it is. You have "spelled out" precisely zero.

Are you trying to tell me that a fork to Keccak (tomorrow) would be as disruptive as a fork to 1TB blocks, tomorrow? C'mon Con. Your superiority can't confer you the luxury of making generalised statements like that, and expecting to project a more specific meaning onto them, can it?

There's no trick question here or lurking 'gotcha' waiting to pounce on you bro.  I only asked you to spell it out because your highly-informed expert opinion is one of the most valuable to me.

I'm not sure you are getting what I'm saying, because you reference "hundreds of millions of dollars worth of mining hardware" that, in a contentious fork war, would have stopped being an asset to Bitcoin and started being a liability (or at least may have entered a grey zone where sha256's value is unclear and possibly zero or negative).

Catastrophic consensus failure would entail that Bitcoin must "start again from scratch."  And facing headwinds of terrible publicity to boot.

In a DEFCON ZERO situation, by switching PoW we would have little to lose (despite the intrinsic chaos involved in moving from one stable state to another), much to gain by defending the blockchain from adversity, and maybe even mitigate the ASIC centralization problem in the process.

Perhaps where we disagree is on the impact of increasing block size on Bitcoin's antifragile aspect.  IMO antifragility is an emergent property of the diverse/diffuse/defensible/resilient network, and anything over 1MB tx + SEGWIT blocks are too risky.

I know that's a controversial opinion, but being out on the fringe isn't so bad when I am in good company with the 'let's consider DECREASING max_block' crowd, to whom I am sympathetic in that I'd rather set max_block at too low a value than too high.

Thanks for stepping into the endless debate to LMK your POV.  I think I got it now, so you can go back to making Bitcoin more awesome!   :)

xpost:

A new challenger emerges.

TLDR: it's Wild Keccak modified to be even more ASIC resistant.  I'm calling it "Feral Keccak."   :P

Divisiveness won't do anything but harm Bitcoin.

Such process concerns belong at BitcoinObituaries.com.

Nothing harms Bitcoin, which always has and always will run on drama.

It's antifragile, so adversity like "divisiveness" only makes it stronger.

You are forgetting that nobody will be interested in doing "51% takeover" on worthless coin, just like today big farms or pools are not pointing their hashing power to mine sha alt coins, taking over their networks and double spend worthless coins.

They have invested a lot of capital into mining BTC,  time is money for them.  If they all agree on mining "classic coin" they will not waste time with "core coin".

If you have more miners mining 'classic' flavour, the longest chain wins.  Period.

The worst part of this whole saga is that "end users" will decide how to solve technical issues.  This does not bode well for long-term viability of bitcoin.

Miners, retailers, end users will all lose if that hard fork happens.  This hard fork is really dangerous now, especially when bitcoin community is already split BEFORE the hard fork.  So yes, I agree, we'll have two coins for a while.

I read most of this thread, and it seems to me that there are a few misconceptions. It is not the miners who determine the price, but the consumers. These are investors, speculators, traders and people who want a convenient money transfer system. If the price drops below the cost of mining, then miners start to sell up. One example of this is the oil industry at the moment. A fracking well in N. Dakota is having to pay to dispose of its oil - they won't be in business for long.

What will happen to Bitcoin? Well imho, it depends on the direction that the full nodes take. There is no point in mining blocks that will get chucked out by the consumers. Also, I haven't seen any comments on the block hijacking that seems to go on between miners. If a block is rejected by the nodes, will another miner be able to grab it, re-populate it, and submite to the core chain? I don't know enough about mining to know if that is feasible or likely, but it does seem as if opportunistic miners could benefit by staying with the core fork.

Except that economics would have to be the only consideration in order for that to happen: it isn't (in either North Dakota fracking wells or Bitcoin mines). That is, to some extent, why what you're talking about isn't happening either.


What fork? There is no fork, and the way things are going, there isn't likely to be a fork any more significant than the orphaned blocks we see every day.


But you seem to be basing alot of your present-day planning around an assumption that the blockchain will fork; to wit, your signature. You have a few misconceptions yourself about the overall picture, I would argue.

It was news a few days ago that a N. Dakota well had to pay for its oil to be removed. It's low grade, and the transport + refining costs made it uneconomic to process. I agree that it's not quite the same. A Bitcoin is a Bitcoin (ignoring ageing and unspent premiums), so there is no significant variation in price between coins.

re. my sig. I'll stay with Bitcoin whatever happens, but I support SegWit, and my sig is a puny attempt to support the true Bitcoin camp, rather thsn the usurpers. :)

I know.


No, I would disagree with your contention that it's "not quite the same"; the operative principles are the same. That's why you drew the analogy to begin with, and that's why I suggested an extension of your metaphor to encompass the full range of factors that affect propensity to sell in either market.


That's cool, but can you see how your sig actually undermines confidence unnecessarily? If people took you seriously they might assume:

• There is a serious risk that the blockchain will fork (there is only a small risk of that)
• 2MB hardfork is in serious contention amongst the devs (it isn't)

There is an unfortunate mob of forum hounds who spend all day, every day, spreading misinformation like the 2 bullet points above. The intention is to do a "Billie Jean": the lie becomes the truth, because everyone is so used to hearing the lie. Watch out for those people, and their rhetoric.

Well my intention wsas to nail my flag to SigWit. I really believe that it is essential to move Bitcoin into a mature phase (and some other changes of course). I know I'm not a significant voice, but multiply my voice a few hundred times, and it might have an effect. What would you suggest as a better sig?

well, I'm not suggesting I actually want you to change it to something else, but just to give it some more thought. I like what you said about multiplicity of voices, and it's more than welcome to get new people coming to bitcointalk, so don't be offended if I come across a bit didactic. But as I said, and as it seems you already know, we have a problem with very insidious bankster trolls over here.

A problem?... It's a downright infestation of bankster trolls up over here. Some have even been lying in hibernation for near half a decade, just shows you how super cereal our opponents are... A quick way to identify them is if they talk about "native scaling", or "outright suicide" if you have your head screwed on straight.

A PoW change may be necessary to shed the fleas for good, via decentralization and censorship resistance.

What block hijacking? If a miner changes something in a block,
he will have to compute a new proof-of-work.

I'm trying to find the discussion about this. It seems that a couple of miners are monitoring activity to see if a block has been partially completed, and then jumping in with a partially populated block to grab the reward before the finder can complete. Now I'm posting this from memory, and I don't understand the stages that miners go through to prove their blocks. Also, I gather that it's only careless miners that leave themselves open to this. If anybody recvognises this description, I'd be grateful for some keywords, so that I can find the article again.

I'm struggling to find this. I wonder if it was something in the discussions about "selfish mining"?

If you mean by partially completed block a one that has not been broadcast,
then that is impossible.. and no miner would broadcast a block that fails to meet
the PoW target.

There is a scenario where a miner can take a valid, broadcast block, stuff in it
some new transactions and start to mine on it, and if he succeeds, he effectively
"hijacks" the reward plus some extra fees. I don't know if that actually occurs, but it could
be seen as a variant of selfish mining (where a miner finds a valid block but does not
broadcast it, instead starts to mine on top of it)

Ah thanks! It was something like that. I'll keep an eye open, and see if it turns up again, It was reported that some miners were scanning activity to detect a vulnerability, and had succeeded a couple of times. Presumably miners will be aware of it, and take suitable precautions. Sorry to be a bit vague, but once again I'm out of my depth (but learning to swim). :)