Topic: Proof of Work: Limit node hashrate to improve decentralisation? (Read 442 times)

Maybe they should but they are not required to in order to run a PoW farm.

A manufacturer attacking a coin where its own machines are neing used would be stupid. The would be shooting themselves in the HEAD. Hahaha!


But miners should care, and they really do. Failure of the network would mean a failure in there mining operation.

This topic is getting ways out of rail, by @mindphuq imo.

I am hardly trying to avoid engaging, but I think it is necessary to remind  that bitcoin has survived enough to prove the solidity of PoW and PoS is just an (both theoretically and practically) unproven alternative unlike what this guy is repeatedly insisting on.

Anyway I think it is not an appropriate practice to come to a topic that is simply about improving PoW this or that way, discussing PoS (weakly if not ridiculously) claimed PoS advantages over PoW and hijacking the thread.

Speaking of improving PoW, I have just started a topic, definitely related to what op has asked in the first post.  obviously, @mindphuq is not invited  

If you would manage to compromise 51%+ of ASICs, how would you maintain the full control over them? What would you try to 'destroy' the network?
Regardless of what you will do with those ASICs to attack the network, it will be WAY LESS profitable than just using them for mining (or destroying them to increase the actual percentage of 'own' hashrate) while you have control over them.




If bitcoin would suffer a 51% attack maintained over multiple hours, the whole cryptomarket would drop in value.
An attacker couldn't 'move on' to the next coin. They all would be worthless. The altcoins would be crashing first, followed by BTC.

This additionally assumes an attacker is able to cash out in a timeframe between the 51% attack and the markets reaction to such an attack, which does not necessarily apply.

The reason 51% are not tried right now is that it is just impossible for a single person to get the ~17 Exahash/s you'd need. That's said for a single person, but not for a pool and also not for a manufactor of a miner who everyone uses. And if you manage to attack the miner's firmware, you'd lose no money at all, same if a pool reaches 51% and you'd attack it.


See above. Also, as said, in PoW miners generally don't care in the coin's health after they cashed out their profit, because they don't need to care about that. They will just move on to the next profitable SHA256 coin and continue. That's because miners in PoW don't have to hold any share in the Blockchain's value. That is different with PoS or with a PoW where you'd have to put a bail on a coin for each block you submit. If miners would care about a coin's health, they wouldn't all just cluster up on the same pools.

In theory your risks are "0" if your only goal was to attack the network and did not mind losing the money spent on the attack. From what I learned, Bitcoin works because it embraces the possibility that it might be attacked, but risks always outweigh the reward.

Maybe the reason why Bitcoin is still standing is because it appeals to the interest of all the miners and the network to be in a state of equilibrium.


Ok.


Haha. But they will lose, everyone loses. The coins will be worthless, the exchanges might stop trading them, and the users will leave. The miners can sell their equipment but it would have been more profitable if they mined the coin honestly. Risks and rewards.

That is true when the foul spending is significantely smaller than the 12.5 BTC (or later on even less). That is a far smaller value you'd destroy than when you have to buy 51% of all coins in existence to attack PoS.


Well as for SHA256 there are plenty of coins to mine on, take alone all the BTC forks.

And both don't apply to governments and other that just want to harm cryptos in general. And please mind the fact that here it was also said that there is an issue with single manufactors having too much power over the mining industry with their firmware and that there are backdoors has been shown with "antbleed".

As for a discussion of security matters, I always found the motivation of a possible attacker not a valid argument. It's like when someone asks why someone should use a secure password for Facebook or their email since they have nothing to hide. You can never expect a reasonable motivation of an attacker.

The one of the biggest strenghts of Blockchains is the decentralisation of the ledger and a pure peer 2 peer network to maintain asset operations. This however doesn't exist if the Blockchain is not well decentralized at all.

Running a full-on 51% attack would likely severly devaluate the PoW coin in question though, which leads to the following:

1) Opportunity cost (ie. by destroying the value of the coin, you also destroy the value of the received block reward)

2) If the PoW coin runs on ASICs, finding a buyer for the mining hardware of the coin you just destroyed won't be easy. Especially at the scale required for a 51% attack.

Yes, there are risks but the risks are at 0% when you have 51% of the network weight. Anything below 51% can make your foul play fail, at 25% you have a 1% chance of success over 10 confirmations. But as soon as you pass 50% you have 100% of success for your foul play, no matter how many confirmations from the network (all full nodes) you get. The propability graph is expotential with reaching 100% at >50%



(see https://bitcoil.co.il/Doublespend.pdf).

BIP148 and NO2X don't fix the majority attack at all.

The "profit and greed" issue has a slightly different aspect. Attacking a PoW coin with 51% would make you lose no money other than what you have spend on energy cost. The mining rig you used for that attack (if it's yours at all) could be sold after the work is done and compensate a part of the energy cost. With PoW you don't need to have any value in the Blockchain, you can point your miners at any Blockchain you desire and the coins you earn will be spend for your profits. In other protocols you risk your own investment in the Blockchain when you attempt to attack it, or as Vitali put it: "Attacking proof of stake is like buying the biggest mining rig and set it on fire".

Maybe "fixed" is not the right word. But we already know that mining is more complicated than "profit" and "greed". There are risk and reward ratios at play if the miner or a group of miners do foul play.

The miners remember BIP148 and NO2X very well.

How does that fix the problem I described?


That's why I posted the link, it's explained there in detail. The code backdoor was fixed already but the problem remains, when a single manufactor basically has control over a large part of the hashrate. In "antbleed" there was a code in the firmware, that allowed Bitmain to shutdown miners, collected metadata about miner usage, expose miner users to government and also could be exploited by third parties due to vulnerability in the backdoor code.

With Bitmain's maschines providing most of the global hashrate, this is still an issue since there is still the possibility for more intended or unintended vulnerabilities in the firmwarecode.

I believe Bitcoin "fixed" that "problem" by embracing the miner' greed. The side effect of a mining "arms race" would be a more secure network.


Bit the miners don't have full control of the network. Read BIP148 and NO2X.


Before imtroducing "antbleed" give us a short explanation about it. But miners have always kept interest in their profit be it they are mining using GPU, CPU, or Asic.


POW change would be better in my opinion, but only as a last resort.

The miner's "arms race" has become the biggest issue for the Blockchain. It doesn't simply work as intended and changes are neccessary to fix this problem.

Yes, the problems are not immanent in the protocol or the design of the Blockchain but rather in the people who use it/respectively try to profit from it. That has allowed manufactors like Bitmain to literally take full control over Bitcoin. And while getblocktemplate was implemented against malintent pool owners or -attackers, the power of miner-manufactors over the blockchain remains unsolved.

Bitmain's own proprietary firmware controls 70% of the global hashrate in Bitcoin.

http://www.antbleed.com/

The mining industry doesn't give a damn for the coin or it's health, all they are interested in is their profit. And PoW enables them to operate and control the Blockchain without requiring them to hold any value in it. If things like "antbleed" continue to exist, PoW is to be considered broken.

Limitation of hashrate, as difficult as it might be to implement, would render all ASICs useless and require people to return to their GPUs and CPUs and thus diverse the hashrate again over a lage variety of firmwares and hardware implementations. If one'd require miners to put a bail on the blocks they create using their own coins they hold, they would be forced to have a value in the blockchain, hold a certain amount of coins for their daily mining business and also risk their bail when they attempt to manipulate the blocks they issue.

Although I am aware that changes like this will probably never be implemented due to the political power miners have over the Blockchain and a change like this would damage their mining business as all ASICs would become worthless over night. That is, unless a huge portion of the community puts pressure on the Chinese mining industry and forces them to comply.


This is true for a commonity like Gold but not for a currency. A currency needs to be stable and fluid.

OP, the miners "arms race" for more hash power is a beautiful thing as it illustrates that the higher the cost, the more scarce Bitcoin is, then the higher the value.

Bitcoin monetization should require high costs and low production if you want high value.

But how do you determine when someone's clock is running? You need to have entities verified and that verification needs to be based on something someone can not easily create out of thin air. You could use addresses to verify but each pool could for each block they issue create a new address. That's why I brought up coin ownership, because that's what PoS uses to limit the amount of blocks someone can create with something they can not create out of thin air. So if you would like to create a block also send a transaction of part of your coins to a stake and then these coins get market as "bail" for the block, this "bail" decays over time until you can use the same coins to issue a new block.

When uitilizing other things, my thoughts often went in the direction of lottery draws. Just make the protocol combine the blockhash with that and you will have to wait until saturday and wednesday before you can go on. So, that "clock" could be replaced by a second coin (complete system), so that the blockchain becomes a hybrid, but then, there's the next thing, the clock, that you can attack, it's infinite regress. I would rather wait for the lottery draws myself if they were each hour, but nobody else would trust it. Some people argue about nuclear war and shooting blockchain data into space. There's no way to convince them of a lottery not being rigged.

Yes, that's basically what Sybil attack means. This would have to be solved to have a hashrate-limit taking place.

Maybe you could tie the hashrate to coins you own. So let's say to issue a block you must prove ownership of a balance and that bail on these coins decays over time before you can use the same coins again to issue a new block. You can not limit nodes but you can utilize other limits everyone has like coin ownership.

Well Monero at least aimed at the CPU miners and didn't cater to GPUs. That is, until ASICs for Monero appeared and all what Monero can do against this is frequently hardforking their coin to a new algorithm to prevent ASICs from taking over.

I wanted to do the same, I think, but for energy saving. The only way I found to be ok-ish was serially hashing in the protocol. Every (efficiently used) additional parrellel node has to wait, but also every user that just wants to verify transactions, so it gets really unusable if you don't have some other measures like trusting serial hashings that have already been done, as a pool would in effect do. https://bitcointalksearch.org/topic/m.34215094 And the other idea in the last post in that thread, higher rewards for waiting, is dangerous because there is of course no objectivity whether waiting took place.

That's not inherently true. The coins can be issued with another algorithm, including PoW, where as PoW-problems will not be such an issue, since in an early stage of a coin's existence there won't be ASICs (if it's using a new algorithm) or alone farms for the coin.

It is only true for premine coins, but it should be clear, that premining a PoS coin is a totally retarded thing to do, unless you provide a plan for a proper distribution before you activate PoS.

Blackcoin for instance started with a PoW/PoS hybride that ran for a week and then was designed to switch to 100% PoS. A few thousand nodes participated in the initial mining and before the first bigger pools adapted the coin, the PoW was closed. The developers of Blackcoin never owned a significant amount of coins.

Similar for coins that already exist like Ethereum, these are decentralized enough to run a PoS.

Also with PoS the richer don't get more rich than other. Everyone gets the same interest rate for their balance, no matter if they own 1 coin or 100k, so the distribution of coins remains roughly the same and doesn't cluster up on a few addresses that been rich from the beginning. In PoW the rich, these that can run mining farms, get everything and everyone else gets nothing.

Bitcoin currently has 3 pools that provide almost 55% of the hashrate and Bitmain miners frequently get over 51%. That means the manufactor of the miners could attempt an 51% attack on Bitcoin with a good chance of success.

As said, getblocktemplate-protocol, if implemented thoroughly, lowers the direct danger of pool centralisation but only to some extend. The big pools and mining farms still have a political power in the coin discussion and need to follow coin updates in order to prevent a fork and manufactors of miners could hide a remote control in their firmware to attack the network.


Every wallet has build in a solo mine function. That's unused for years now since pools and ASICs took over and no one bothers to mine on their CPU let alone solo-mine. The initial idea was to run a decentralized peer to peer currency where every participant can at anytime participate to provide support for the infrastructure. That idea is completely broken by now as Bitcoin, Ethereum and other significant PoW coins are almost entirely operated by big mining farms and manufactors in China, who don't have any other interest in the coin but their mere profit. With that motivation, they run the network and influence the coin politics. And that is a bad thing and everything else but a dencentralized peer to peer solution for assets.