[Dev] Kimoto gravity well integration - Feathercoind 0.8.5.1

chrisj

Is there any argument to make against?

slavco

This method gives protection from multi pools fast “attack”. But does this method protects the loyal miners from longer attack?

Scenario:

Huge scrypt farm come to the FTC network and stays for a period of time
diff. will go insane fast
loyal small miners would be there unprotected no chances to mine a block

My toughs:

1. multi pools could be defeated if we play their game by their rules
2. We need unique PoW

kris_davison

If its a long term move to mining FTC is it really a multicoin hopping attack? (unless you mean 51%)

slavco

Multi pools issue isn’t tech. issue but it’s financial issue ( Doesn’t harm the network but mines a coins and then convert them into another currency ). Multi pools would mine a coin until mining is most profitable ( there is tight connections with it’s price ) no matter how big/low is difficulty or block reward.

I’m not pointing out to 51% attack ( we have protection from it ) but I’m pointing out to situation where miner with 30% of hash power could cause 10% loyal miners to abandon the currency. ( We need to check the numbers and make correct simulation about all of the possible scenarios )

kris_davison

Other than the difficulty retarget issue I’m not sure if anything needs to be done.

If difficulty does up and price does not follow profit miners will disperse as its just a market but loyal members would likely stay and maintain the network resilience.

There has been talk already on this forum on people mining coins other than FTC and selling them for FTC to help increase the buy market for FTC.
So even if people did leave then this would be ok. The difficulty would adjust anyway if miners left possibly making the coin profitable to mine again. lol

its a vicious circle but a healthy one.

If we could make the multipool attack last only one block before a difficulty adjustment then loyal miners would be affected far less and I think this would solve the problem.

slavco

If we have a situation where all of multi pools are connected to the FTC network for a long time then we can expect multi pools for sha256 that will pay off the miners with FTC :)))

wrapper

[quote name=“kris_davison” post=“58692” timestamp=“1392213272”]
If we could make the multipool attack last only one block before a difficulty adjustment then loyal miners would be affected far less and I think this would solve the problem.
[/quote]

I agree, even the single block Difficulty adjustment isn’t the full answer, could be a problem. We already have some protection against difficulty drive up, single block might negate that.

wrapper

Heres a really good explaination of whats goin on in the Kimoto algorythm…

http://bitcoin.stackexchange.com/questions/21730/how-does-the-kimoto-gravity-well-regulate-difficulty

wrapper

Maxcoin has Kimoto, Dogecoin consider it.

http://www.benzinga.com/news/14/02/4283374/the-next-altcoin-to-hit-20-million

Yeah… I’m gonna follow this topic.

I’ll have a solid read when I get back from work.

wrapper

Orbits.

I am now starting to get a different picture of how the Kimoto Gravity well is suposed to work, and be understand weither the code actually does that.

The block time can be seen as an orbit around its required 2.5 min timeing for Feathercoin. If all is well, a block will appear at -1.25 and +1.25 mins.

The algorythm then loops back through a number of historical blocks to find the deviation of the orbit. The more deviation, the more gravity is applied.

The main action of the gravity well will be to adjust the Retarget more often, and take acount of “sudden variations” in Hash rate.

HopeStillFlies

Mooncoin has added it. FWIW.

MrWyrm

Orbits.

I am now starting to get a different picture of how the Kimoto Gravity well is suposed to work, and be understand weither the code actually does that.

The block time can be seen as an orbit around its required 2.5 min timeing for Feathercoin. If all is well, a block will appear at -1.25 and +1.25 mins.

The algorythm then loops back through a number of historical blocks to find the deviation of the orbit. The more deviation, the more gravity is applied.

The main action of the gravity well will be to adgust the Retarget more often, and take acount of “sudden variations” in Hash rate.

Thanks, that makes much more sense.

Just out of curiosity, aside from KGW (which is really popular right now, almost every new coin seems to be implementing it at the moment), what other ways could we protect against crazy difficulty traps?

In regards to KGW, I echo chrisj’s thoughts.

Is there any argument to make against?

Keeping ftc ahead of the game is always a +1.

So, are there any arguments against KGW?

I don’t understand it thoroughly enough to try find anything wrong with it.

Wellenreiter

At least it needs to be tuned and applied carefully.

The blockchain is a control loop (I hope the term is correct, got it from leo.org)

Basically it works like

Measure block spacing-> blockspacing lower 2.5 mins?-> if yes increase difficulty
-> if no decrease difficulty

The KGW represents a fast reacting algorithm to adjust difficulty.
Fast reacting control loop tend to oscillate and this could lead to unnecessary jumps in difficulty and make things worse.

It may take some time to find the best parameter to be applied to KGW to get it working even with extreme jumps in hashrate.

Also it will need more calculations to get the new difficulty as it recursively looks back to recent blocks.

With a max block lookback of 10 it’s already 2939328000 calculations ( 1*2*3*4*5*6*7*8*9*10 ).

+1 Wellenreiter

I understand KGW a lot better when you put it like that.

surfguy72

Thanks for this discussion. I believe a change is needed, and you’re all the ones to make it happen. I’m trying to understand the tech part, but I do understand the results, and I believe a change is needed. I really appreciate this discussion, and will pop back in.

Bona Fortuna

SerenaBic

The theme is interesting, I will take part in discussion.

The theme is interesting, I will take part in discussion.

What do you think of KGW?

We could implement it, but there is talk that it is not perfect… What is your take on the matter SerenaBic?

wrapper

There are varying elements to consider when modifying a fundemental protocol element, like difficulty calculation. One of which is energy consumption.

Can any one help with their analysis of the code? main.cpp

Is the next difficulty change calculated by each miner, then submitted when you win? Or, does the winning miner get to calculate the next difficulty on winning the Block?

The the former then, energy use consideration might apply and would be usefull to understand.