Hi all, >>> A 51% attack under proof-of-work is only possible, in general, if some >>> singular entity were able to have physical control of almost 50%, or some >>> such close number, of the globe, simply due to the fact that energy >>> availability is somewhat distributed over the globe.
Mining is not only about the energy sources, individual miners spread around the globe can join big mining pools, and these mining pools could be hacked to participate in a 51% attack. Some governments (or other groups) could plan this type of attack if it's in their interest. If you look at this graph you will see that controlling 4 mining pools could be enough: https://www.blockchain.com/en/pools >>> Secondly: change of hashing algorithm is pointless in the highly unlikely >>> case of a 51% attack, because what matters is control of energy sources. As far as I know, if the PoW algorithm changes to an ASIC resistant algorithm that can only run in GPUs or CPUs, the hashing power would be much more distributed at least until someone creates a new ASIC for that algorithm. There are many GPUs around the globe, but not so many ASIC miners right? >>> Nothing can be more efficient than proof-of-work, and the proof-of-stake >>> delusion is simply a perpetual motion machine that attempts to get >>> something from nothing. As time passes and more PoS coins appears, including big projects like Ethereum, we will see if it's delusional or not 🙂 I forgot one, if you do a 51% attack to a PoS coin you know that all your staking funds will be burned. In a PoW coin you don't lose your miners and can use them to mine or attack another coin with the same algorithm. >>> You must understand that removing the chain tip puts the transactions in >>> that block back in the mempool, before we ever start following the longer >>> chain. Yep but it could make double spend attacks very easy. People would know what is happening and could send the money to themselves with a higher fee to recover it. Many people would lose money with that. To fix that problem with a PoS algorithm, some community-guided initiative could get all transactions of both chains and create a merged chain with a hard fork so double spends attacks would not be possible. This could be somewhat slow, maybe the network is stopped a few days, but in the end no one will see money disappear from their wallet, much better than pray that your payer doesn't send the money back ato himself. >>> Hard forks are very difficult to coordinate as the user set increases in >>> size. I don't think many people will vote against a hard fork if the network is clearly under a 51% attack or the blockchain has 2 branches longer than N due to an internet split. >>> This solution is worse than the problem, and speeds up the dominance of >>> large stakers over the coin, trivially letting someone with the largest >>> stake in the coin grow their stake even faster. I think it's very evident that the rich guy earn coins faster in both algorithms. In PoS if you have 51% of the coins and use them to stake, you make 51% of the blocks, I don't see any problem with that. If you decide to do a 51% attack, stopping doing blocks in the main chain to force the others to follow your "private" chain, well, you know for sure your funds will be burned in the next hard fork. >>> No, I think it will be very successful in ensuring that smart individuals >>> will spend their time actually doing things that benefit the economy and >>> technology instead of wasting their time being distracted with Ethereum and >>> proof-of-stake. Ok, we the PoS advocates will let the smart people to work in more difficult issues like finding reasons to justify the energy waste and heat generation of PoW when Bitcoin price reaches 1 million dollars 😉 Regards, ________________________________ From: ZmnSCPxj <zmnsc...@protonmail.com> Sent: Thursday, July 18, 2019 16:15 To: Kenshiro [] Cc: Eric Voskuil; Bitcoin Protocol Discussion Subject: Re: [bitcoin-dev] Secure Proof Of Stake implementation on Bitcoin Good morning, > I think there is some misunderstanding here. A single node can be isolated > from the rest of the network any time and when it reconnects it only has to > follow the longest chain as always. Checking with a block-explorer or a > friend's node is only required under the extreme situation of being under a > 51% attack, but that is also a problem for Proof Of Work. Both protocols > require manual intervention: > > -PoS: Burn the funds of the attacker with a hard fork > -PoW: Change the PoW algorithm with a hard fork Again: under proof-of-work, 51% attacks are a lot less feasible than under proof-of-stake. You really should have researched this by this point, but in any case. The primary source of energy on Earth is the formation of the solar system. Some areas were seeded with radioactive materials. Later on, some areas were seeded with carbohydrates from dying biological processes. Regardless, continuously the sun shines upon the just and unjust alike. Thus, while there is significant variance in energy availability, it is still reasonably spread out. A 51% attack under proof-of-work is only possible, in general, if some singular entity were able to have physical control of almost 50%, or some such close number, of the globe, simply due to the fact that energy availability is somewhat distributed over the globe. Looking into latest human political maps, I cannot find any singular entity that can claim this. Secondly: change of hashing algorithm is pointless in the highly unlikely case of a 51% attack, because what matters is control of energy sources. In case of hashing algorithm change, the exact same sources of energy can be utilized with whatever hardware is most efficient, and distribution of hashpower will still be the same. The fact that proof-of-work is strongly bound to physical limitations is a feature, not a bug. Economic incentives imply simply that market forces will move hashpower towards efficient usage. Nothing can be more efficient than proof-of-work, and the proof-of-stake delusion is simply a perpetual motion machine that attempts to get something from nothing. > > The other extreme situation would be if the network or internet itself is > splitted more than N blocks. If that happens, it should require manual > intervention to merge both chains. But in PoW it's much worse because the > longest chain wins and it erases all history of the losing chain. Are you > sure that's better? All transactions of one day (or more) could be erased > forever. Yes, that is better. You must understand that removing the chain tip puts the transactions in that block back in the mempool, before we ever start following the longer chain. Thus, transactions on the shorter chain will simply find themselves in the mempool waiting to be confirmed again. Of course, they are still subject to replacement since they become unconfirmed, and there is still some risk involved. > >>>To expand on this: by censoring ***all*** transactions one is able to > >>>prevent spending of all funds. > This will crash the value of the staked funds also, but note that the staker > could use techniques like short options to leverage this and potentially earn > more than the value of their staked funds, effectively stealing the entire > marketcap of the attacked coin. > > Yes but I think this can be solved in PoS, because there should be only 2 > possible cases: > > 1 - The attacker doesn't stop making blocks in the main chain an he only > censors transactions in his blocks: in this case, there is always some honest > block so he can only slow the network > 2 - The attacker does a 51% attack stopping doing blocks in the main chain, > so the longest chain is his "private" chain which only has his blocks: then > he can censor every transaction, but that attack is very evident and a hard > fork could burn his funds. Do note the comment of "political money". Hard forks are very difficult to coordinate as the user set increases in size. > > >>> Aside from that, this is possible to evade by running 10000 masternodes > >>> and splitting your staking funds among them. > > It's possible to give more staking weight to coins together in a single > address than splitted coins like with this formula (or some improved version) > > stakingWeight = numberOfCoins ^ 1000 This solution is worse than the problem, and speeds up the dominance of large stakers over the coin, trivially letting someone with the largest stake in the coin grow their stake even faster. > >>> Another thing is that Ethereum itself is going to PoS next year, but with > >>> a different implementation that I'm proposing here. > > >>>Just another nail in the coffin. > > Do you think Ethereum PoS will fail? > No, I think it will be very successful in ensuring that smart individuals will spend their time actually doing things that benefit the economy and technology instead of wasting their time being distracted with Ethereum and proof-of-stake. Regards, ZmnSCPxj
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