Topic: A Two-Round Proof of Work instead of PoW - page 4. (Read 834 times)

Say round 1 only takes 2 minutes to get 100 miners. Then you just wait 8 minutes to select the "winner".  That's a 10 minute block time. So it saves 8 minutes of hashing. Less global warming.

There is an upper limit for N2 otherwise, the whole thing will be worthless. The idea is to limit the electricity consumption
so N2  <<< N1 = number of all miners.


Thank you for your great sharing and ideas. Much appreciated.

This is a good point, but slightly incomplete: it's the total of resource consumption that depends on the value of the block reward. So if the energy consumption goes down, competing miners would buy more hardware, which moves the pollution to a different location.

What's stopping the remaining miners from doing a "51% attack", trying to beat the select few by creating their own new Round 1 followed by their own Round 2?

Again like in Bitcoin, we take the longest chain. No difference with Bitcoin. The honest and fastest miner will always win in the long run.

you can pretend, but if you don't follow the TRPoW instructions, you will be ignored by the network. Keep in mind that in order to win a block reward, you need to be in the list of N2 miners of other miners.

You can pretend and create a fork. but your block will be ignored in similar fashion like in Bitcoin. No difference here with Bitcoin.

Did you see these instructions ?

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 comeptition. 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.

Thank you very much Bro. I tried this morning on Way back machine but I did not find it.
Thank you for taking time to share it here. Much Appreciated.


Yea. I can see its use for mining pools.


You can't game because of the public key in the hash. Plus in order to move to Round 2 you will need to announce it to the network by broadcasting your nonce1. So if you are a bit late your name won't on the list of N2 miners in other miners lists.

In the second round you hash the following: Hash(Block Head + Public Key + Nonce1 + Nonce). So if you cheat, other miners will detect you and ignore your block. Exactly like Bitcoin.



I do think that TRPoW is doing something different from Luck. We are not solving the same problems. I did not read all the Luck whitepaper, but from what I saw, we are already different.  


Yes. But like in Bitcoin, You can cheat and not follow the rules. But the network will simply ignore you by using the longest chain. You will be served better by following the rules.


The N2 number of miners of the second Round is also adjustable like the complexity algorithm in PoW that is adjusted every 2016 Block.
Plus In Round 1 we are hashing Hash(Block Head + PublicKey + Nonce). So I don't know how this is going to force miners to organize in big pools. The Public Key of a miner has the benefit of limiting the formation of pools. In BTC PoW there is no public key in the hash. In TRPoW, the hash result is public key dependent

But you can pretend that you were. How it is decided who were in the first round? By Proof of Work, right? So if you have some higher Proof of Work, you can pretend that the miner with the lower work came later. And if the total Proof of Work is used to decide who tells the truth, then miners with more power always win.

So each group of 100 miners can pretend that they were first. When you join the network after they are formed in some groups, how are you going to choose the right chain? You can see 100 honest miners with some Proof of Work and 100 dishonest miners with another Proof of Work. If the most Proof of Work after two phases dictates the truth, then people are encouraged to kick other players from top100 by creating their own lists of top100. You cannot assume that all miners are online 24/7, you have to assume that someone can be offline for a while and then there should be some way to know which chain is the right one. The same is true for new miners, they know nothing about the network, they connect for the first time and they see some groups of top100 miners from the first phase. They have to know somehow, which group is the right one.

Also, Luck coin encountered the same problem in the early stage. When the difficulty was low, everyone could pretend to be a true winner in the first phase. There were some alternative chains, the official block explorer showed block 500-something, but people were stuck at 200-something or 300-something. Then, when difficulty raised to some higher levels, everyone received the right chain, but then small miners were kicked and mined one block per week or so.

If there is no upper limit for the N2 number of miners, then it will grow exponentially ad infinitum, people will spam the chain by pretending there are millions of miners, even if there will really be only 10 or 20. But if there will be some limit, for example there will be max 5000 miners, then you will reach that maximum and then the second phase will behave exactly as any other single-phase Proof of Work.

The N2 number of miners of the second Round is also adjustable like the complexity algorithm in PoW that is adjusted every 2016 Block.
Plus In Round 1 we are hashing Hash(Block Head + PublicKey + Nonce). So I don't know how this is going to force miners to organize in big pools. The Public Key of a miner has the benefit of limiting the formation of pools. In BTC PoW there is no public key in the hash. In TRPoW, the hash result is public key dependent.    

 

The PoW job is also to maintain the Block Time at 10min. We can achieve that by just making everyone wait for that 10min minus delay/network broadcasting time etc.

I think you need to have some skin in the game if you 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.

Could you please explain to me how you are going to attack by kicking someone from Top100 ?

Keep in mind that in order to move to Round 2 you need to Announce it to the network by Broadcasting your solution of Nonce1 and your list of N2** miners up to the moment you found your nonce1. For the round 2 you hash the following:

Hash(BlockHead + PublicKey + Nonce1 + RandomNonce)

So you will always need to show that you were in Round 1 at some points. And if you are late, the network will have already formed its lists of N2 and you will be outside of it.

And your block will be accepted ONLY if your name was in the List of N2 of other miners.

Thank you

In a real world with TRPoW, most miners will spend their time working on Block Round 1, because the round 2 is limited only to the fastest few N2 miners, so attacking by kicking someone from that top100 and taking its place is more profitable than honestly waiting for the next block. Because kicking other miners from top100 is more profitable than doing nothing, everything can be reduced just to phase one, then phase two is the easiest part, needed only because consensus rules says so.

Also read this: https://www.truthcoin.info/blog/pow-cheapest/#nonproductive-investments-are-wasteful. Not only it explains why other solutions like Proof of Stake or Proof of Capacity are worse, but it also explains why any two-phases or N-phases solutions are pointless (and can be reduced to the old, plain, unobscured version of single-phase Proof of Work). The reason is the same: you have some simple economic rules, miners are trying to maximize their income, and making some official version that is "honest" is not enough to stop the coin from attacks. Even if your version is eco-friendly and stops mining when you didn't get into the second phase, other nodes may still keep mining, then an alternative version can be more popular, as it happened in many successful coins (including Bitcoin, because mining pools have their own optimized versions, they are not mining with their CPU's by using Bitcoin Core's default mining implementation).

It does not matter what is your goal. If you use the same tools to reach it, you will encounter the same problems. Even source code for Luck is still on GitHub, so you can still download it, see how they splitted the whole process into two phases and why it does not work as expected. Also you can see their Discord channel and watch some charts showing how some parameters of each phase changed in time, and how one huge mining pool reached 51% by gaming the first phase with his own software. Also I described it here, how they calculate their parameters: https://www.publish0x.com/vjudeu/two-phase-proof-of-work-as-a-solution-to-mining-pools-xrommel

I think there will be only a few miners in the testnet (assuming testnet coins will be worthless or destroyed after testing), a lot of miners in the first seconds after releasing the software (so that if it will be published on centralized servers, they could reach Error 500 because of too much traffic), then the difficulty will skyrocket and the coin will be worth a lot in some Discord-based P2P trades. And then it will enter some exchange, everyone will cash out and the price will go from All Time High to All Time Low.

But it happened in many altcoins, including Luck, when they splitted mining into two phases, many people were mining with the original software, and one mining pool gamed the whole system and reached 51% quite quickly. Also some FPGA miners gamed the system, they competed with CPU's, so they win, because mining algorithm was not resistant to that. Also, the question is: which hash function you are going to use? If you use just sha256d as Bitcoin, the competition will eat you one minute after release.

No. The miners have incentives to not 51% attack the network. If they try this, the value of their equipment to drop >99% overnight.

Miners engaging in activity similar to what I described is similar to miners attempting to keeping their equipment that has a limited shelf life working as much as possible.

This is similar to say that miners will organize themselves in big pools to organize a 51% attack on Bitcoin network. It did not happen so far.

You could but if I'm understanding the OP proposal correctly is that he will only allow a certain # of miners into round 2, such as 100. How those would get chosen he said it is based on the first 100 that solve the puzzle. So in that sense, if you increased your hash rate then it would increase your chances of getting into round 2. So your question is valid. The answer is you would use as much power as is necessary to be in the top 100 but no more.

Not sure on that. But why not just have a single round 1 and just select the winner at random without eliminating anyone? Why wouldn't that work?

In an ideal world with TRPoW, most miners will spend their time moving from one Block Round 1 to another Block Round 1 because the round 2 is limited only to the fastest few N2 miners. And hence we will able to reduce the electricity from not involving everyone to go on a spree of CPU intensive hashing all the time.

So the idea is not to advice for LESS CPU power but to create a system that do the same thing like BTC with less electricity consumption.

So then, why would miners use less power?

You state "In the first round, we run a similar Bitcoin PoW..." If the first round is similar to Bitcoin PoW, then it has the same economic incentives, in which the cost of mining is limited only by the value of the block reward, regardless of the complexity. It seems to me (I may be wrong) that you may be succumbing to a fallacy similar to the belief that more efficient miners (in terms of J/hash) in the future will cause the overall power consumption of mining to fall.

If you use more CPU power, you have always better chance to advance to Round 2. However, because Round 1 is not CPU computing, small players will be able to advance to Round 2 too. It is like we are giving more chances to small players to earn.

About your second point, let's me reflect on it.

I'm sure the miners wouldn't be supporting such a thing because it just makes it even harder for them to get a reward.


I wonder if the people that wrote that paper realized that. that's thinking ahead! the bitcoin mining system is really hard to make changes to without causing things to get "out of whack"

Wayback Machine still has it, as well as some lucknet.club pages: http://web.archive.org/web/20201201172513/https://lucknet.club/doc/luck.pdf

But you know that Bitcoin blocks are produced in a similar way? Small miners include public keys for mining pools, so even if all blocks will be signed by miner's keys, it won't change anything. You can have one phase, two phases or N phases, it doesn't matter. Pools are going to download your client and behave like any other network participants. Then, they will be connected with hundreds of nodes and rewarding them "per share", no matter how complex that single share will be and how many phases will be needed to get it.

If you have something that is not computing-intensive, then the energy consumption is reduced, but along with security. I guess the same thing could happen as in Luck: if you have two phases and they are not equally hard, then miners can game the system by dividing it differently between those two phases than you did in the original software. For example, your official client can mine the first phase for a short time and spend the most of the time on the second phase. But some optimized version could do the opposite: spend a lot of time on the first phase to pretend there are millions of miners, and then quickly solve the easiest blocks by completing the second phase.

Or maybe they will find an equillibrium somewhere in between, maybe with the same amount of time for each phase, maybe 2/3 for the first and 1/3 for the second one, it really depends on your network parameters. In Luck it reached the highest limits they chose, as far as I remember their "alpha" value exponentially increased to the maximum value and stayed there, because that case was the most profitable for huge miners. In their first version there was no such limit, so without their first hard-fork, the network would be dominated by the biggest miners forever.

You cannot assume that all miners will follow the rules, just because you placed them in your client. Rules have to be wired in the protocol to be followed, if some rule is only client-specific, it can be bypassed. For every successful coin you can find custom miner software, where miners optimize things far beyond what you gave them in the official version.

Also, if there are millions of miners and you randomly select 100 of them, you encourage the rest of the miners to form mining pools. Then, you will end up in a situation where 100 miners are selected as before, but there are only 100 huge mining pools, they always get everything and distribute that to smaller miners. Almost no solo miner will follow your system if that miner will be rewarded once per month, because the risk of price drop after entering exchange is higher than the potential reward from solo mining.