Topic: A Two-Round Proof of Work instead of PoW - page 3. (Read 718 times)

Yes it does. It makes half PoW and half of luck. If this is good, then make it 100% luck. does it work? No. Its not secure.
This propose just lower security for name of "economical".

Some of them are idle, some of them are not. You can release a software where the miner stops, but if it is open-source, then miners can decide they want to compute hashes all the time, because then they have a chance to produce another valid Proof of Work. Even if some old nodes will not accept that, still, there will be new nodes and new miners that will know nothing about the past events in that network and will have no way to check, which Proof of Work is the right one.

Doesn't this scheme compromise the security of the bitcoin network. I mean, the security aspect of it is based on the total hashrate at every moment in time. if at any moment it decreases...then there's a potential weakness.

Yes but Round one is only let's say 2min for the sake of argument. Once this 2min is over Only N2 miners will advance to Round 2 to work on the second puzzle. Let's assume Round 2 calculation time is 6min. We have N1 miners working for 2min and N2 miners working for (2+6)=8min. In Bitcoin we have all N1 working all 8min. We save energy on Round 2. N1-N2 miners are IDLE during 6min of Round 2. This is where we save energy. Now I do understand that miners can try to game the system and rent their machines to the winners of Round 2. But I don't know how practical it can be to do so.   

Please explain how a lower complexity reduces the amount of energy used when miners are encouraged to increase energy usage in order to be one of the first N2 miners. Whether it takes 1000000 tries on average or 10¹⁸ tries on average, miners are going to use as much energy as they can in order to be first.

The complexity in Round 1 is supposed to be small. Which means that most of honest miners will quickly find out if they need to move to Round 2 or not. Round 2 being limited to the fasted few N2. This will make most of miners idle / preparing for the next block which is not Energy-consuming. In Bitcoin today, most miners spend their time calculating the Hash puzzle most of the Block time (7 to 10min). So if we reduce Round 1 time to 1-4min or even more, it will be great. It is yet to be tested in grandeur nature.
        

I don't think it is possible to have a single N2 list. Each miner that completes round 1 will have a list that may be different from every other miner's list. Furthermore, there is no way to agree on which miners were the first miners to complete round 1 because there is no way to resolve the differences in the lists.

The energy saving comes from the fact that most of miners will spend a big part of their time on Round 1 that is not heavy-energy / CPU consuming. At least this is the target, the bet and the hope.  

wait, so you're saying that 2 blocks are going to be produced? one in round 1 and one in round 2? that's starting to get confusing. maybe we need someone to break this down and explain exactly what is going on so that it is understandable because the way you explained it right now makes it seem like there are going to need to be 2 blocks, one for each round. does that double the blockchain size?

The public key associated with the address 1KFHE7w8BhaENAswwryaoccDb6qcT6DbYY belongs to the mining pool f2pool. There are thousands (if not more) of miners who mine on f2pool, but all of f2pool's found blocks payout to the above address.

If f2pool makes it to the second round, any miner who is not participating in the second round will switch to mining on f2pool, or another pool that is participating in the second round. If a miner sits idle (or is not otherwise producing work that has the potential to find a block) during the second round, their equipment is losing out on potential value.

The difficulty of the first round could be "x", and the difficulty of the second round would be "10000x". Each of the miners who are "selected" during the first round could need to have their "block" include the hash of the previous block, and the first "block" in the first round would need to include the hash of block found in the second round. The found block in the second round would need to sign the hash of the last block of the first round. This is very similar to how bitcoin mining occurs today.

I don't think that's the issue. I think the real issue is a blockchain has no way of measuring "time". It doesn't know how to measure 8 minutes. But there has to be a way.

What is the probability of an honest longest chain be outside the N2 List (Or we can extend it a bit to N2 List of N2 miners because each miner who succeed Round 1 is broadcasting its List. But we don't need to as we can just merge the lists and put a cap at N2)? Anyway, this probabilistic problem is similar to the AT2 problem discussed by Rachid Guerraoui team in EPFL. I will share the Math later.  But it can be found in their AT2 paper (In fact they published 3 papers). Based on AT2 papers, N2 does not need to be big to achieve our purpose.

Where is the energy saving here, when the miner will have lower electricity bills, but there will be more miners?

And the statements that Bitcoin "waste" energy (and consequently imply that something needs to be done about it) haven't been debunked many times?

How is #1 enforced? What prevents a miner from executing #2 if it finds its own $nonce1$ after it has already received $N_2$ $nonce1$? A violation of #1 cannot be detected.


Nothing in your miner instructions ensures that every miner has the same list of $N_2$ miners. Therefore, #5 will cause a split that cannot be resolved by the longest chain because a block by a miner not in another miner's list for that block is not considered valid by that miner.

Even if you can successfully prevent that knowledge for 8 minutes, someone can still start working on some randomly chosen block and have hope it will give some boost on average, where other miners will be idle. Also, you need at least two candidates, in other case any obfuscation of the winner is pointless. Does it mean that nobody can start the chain alone by using the official miner?

Another thing is getting the right to mine: one miner can pretend to be N miners or can just own many mining machines and assign different keys to each of them. Then, if the list of participants is known, any miner can try to extend any block, just by checking each of them sequentially, or even assigning different threads to different blocks. Extending one of N blocks has the same probability as extending some chosen block. Because having a chance to mine the right block is better than having no chances by being idle, people will run their machines all the time.

No. But we don't need it. If there are different lists the network with go with the longest chain like in BTC.


Please Read instructions 1) and 5) below.
 
===========TRPoW miners will execute the following instructions============================

1- If a miner receive $N_2$ $nonce1$ or more broadcast from other miners before finding its own $nonce1$, it will broadcast the list of the first $N_2$ winners and drop the current block competition and move to the next block. In this case it failed the first round and the block reward.
2- If it finds its $nonce1$ before receiving $N_2 - 1$ solutions from other miners, it will broadcast its $nonce1$ with the list of all the miners that found the solution before it including itself. it will continue listening the network to build the full list of the first $N_2$ winners. And at the same time move to the next round competition. In this case it succeed the first round.
3- If it didn't find its $nonce1$ yet and did not receive yet the full list of $N_2$ winners, it will continue solving for its first round $nonce1$ and listening to the network broadcasting to build its list of $N_2$ winners. In this case it is still running the first round.
4- If it finds its $nonce2$ before receiving any valid $nonce2$, it will broadcast its $nonce2$ and update the ledger and register the block reward for itself. And move to the next block. In this case it won the current block reward.
5- If it receive an $nonce2$, it will verify the solution and verify that the miner is in its list of winners of the first round. If all is fine, it will move to the next block competition having failed the current block competition. If the miner is not in its list of winners of the first round, it will ignore what it received and continue solving for its own $nonce1$ or / and $nonce2$ and listening to the network.

You would need a way to prevent the knowledge of the winner for 8 minutes so that nobody can start on the next block before the 10 minutes have past.

This is true...

But I think miners need to have some skin in the game if we want to have long term serious players in the network. PoW is achieving this skin in the game by asking for CPU power and PoS is achieving the same by asking for stakes.

We can imagine that a lot of fastest miners will always be in the second Round 2. So those will win the race for the Block. In short the honest and fastest will win in the long run.

Those disqualified in the first Round will lag behind and the block they will create will be a fork and it will discounted by the network as most miners will always go with the longest chain. 

The first N2 solutions received by one miner could be different from the first N2 received by another. Do you have a way to achieve consensus on who is in the list? If there are different lists, then the network will split when miners don't agree on who is in the list.


If you don't accept a block by someone not in your list, then you can't follow the actual longest chain. If you allow a block from a miner not in your list then every miner can include themselves in their own list (as soon as they complete round 1), which you must accept in order to resolve a split.