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Topic: Security analysis of PoW/PoS hybrids with low PoW reward (Read 13280 times)

member
Activity: 65
Merit: 10
Just read through this thread. Lots of good info. Any updates to these security flaws?
legendary
Activity: 1946
Merit: 1012
vertex output parameter not completely initialized
Hi

Is a classic standart non-POS sCrypt (end of POW) easily attackable ?
sr. member
Activity: 393
Merit: 250
I am trying to qualify the claim made by the OP, that MintCoin had no PoS block in a hour.

What is the proof that this was because of the "attack", or there was just nothing to stake during that hour?

Also, how would an PoS block in a hybrid coin "invalidate many PoW blocks"? The PoW and PoS chains are pretty much independent, no?
hero member
Activity: 868
Merit: 1000
I'm a MINT investor and want to thank you guys for exposing the issue. and no destroying the coin


 i never bash people and dont know why MINT people did.


thanks again.




sr. member
Activity: 364
Merit: 250
Quote
Or, do not allow two PoW blocks in a row.

What about this idea? Can it be implemented? And is it worth doing?

Wouldn't this be the same as raising the PoW difficulty to the level that only one PoW would be generated in the time one PoS block gets generated? I don't really see the difference.

it wouldn't require that minors participate for a low block reward, yet you receive the same result
sr. member
Activity: 248
Merit: 250
Quote
Or, do not allow two PoW blocks in a row.

What about this idea? Can it be implemented? And is it worth doing?

Wouldn't this be the same as raising the PoW difficulty to the level that only one PoW would be generated in the time one PoS block gets generated? I don't really see the difference.
legendary
Activity: 2044
Merit: 1005
Were not there other ways to fix this issue?

For example, if the problem is PoW difficulty gets too low, why not set a minimum difficulty for PoW mining?

Or, do not allow two PoW blocks in a row.  Enforce that a least one PoS block is between each PoW block?

I think those fixes might be better than to just eliminating PoW altogether.  Just trying to understand this better.

If you set a lower bound to the difficulty that is much larger than the actual difficulty level then it is absolutely not profitable for any miner to generate PoW blocks anymore which basically leads to the same problem.
Most of the premined pos coins are not profitable to mine pow anyway.. 1 coin per block at 20 sats.

I figure the devs were either lazy or dont understand the code enough to fully remove pow thus they just set the reward to the minimum so its quick and dirty. In reality if the pow is not helping with block authentication it
should be removed... surely devs knew if a hybrid approach was beneficial or not to the security against attacks that are common sense with both pow and pos?
sr. member
Activity: 364
Merit: 250
Quote
Or, do not allow two PoW blocks in a row.

What about this idea? Can it be implemented? And is it worth doing?
sr. member
Activity: 248
Merit: 250
Were not there other ways to fix this issue?

For example, if the problem is PoW difficulty gets too low, why not set a minimum difficulty for PoW mining?

Or, do not allow two PoW blocks in a row.  Enforce that a least one PoS block is between each PoW block?

I think those fixes might be better than to just eliminating PoW altogether.  Just trying to understand this better.

If you set a lower bound to the difficulty that is much larger than the actual difficulty level then it is absolutely not profitable for any miner to generate PoW blocks anymore which basically leads to the same problem.
newbie
Activity: 23
Merit: 0
Were not there other ways to fix this issue?

For example, if the problem is PoW difficulty gets too low, why not set a minimum difficulty for PoW mining?

Or, do not allow two PoW blocks in a row.  Enforce that a least one PoS block is between each PoW block?

I think those fixes might be better than to just eliminating PoW altogether.  Just trying to understand this better.
legendary
Activity: 1246
Merit: 1000
103 days, 21 hours and 10 minutes.
Hmm I know what I'm trying out tomorrow morning

 Roll Eyes
hero member
Activity: 868
Merit: 1000
Not really a big deal, if it is an issue just fork it to not accept any more POW blocks.

Looks like I called it on the first page. Thanks rat4 for exposing the flaw and not leaving anybody with a bag of unconfirmed mints. Good guy dev makes competing coin more secure.

+1. And sorry for being rude and assumptious with my initial post of this thread, it was uncalled for.
legendary
Activity: 980
Merit: 1004
Not really a big deal, if it is an issue just fork it to not accept any more POW blocks.

Looks like I called it on the first page. Thanks rat4 for exposing the flaw and not leaving anybody with a bag of unconfirmed mints. Good guy dev makes competing coin more secure.
hero member
Activity: 868
Merit: 1000
Thank you for your help Blackcoin community, you know which people you are (rat4, Soepkip, etc). Perhaps now we can put our differences aside and work together or at the very least coexists as pure PoS coins.

Update on the potential security issues mentioned earlier.

As a cautionary measure and since MINT does not really need PoW, we have decided to get rid of the PoW. We don't want to take any security risk.
And since our ego is less important than your hard earned money, we won't have any problem to be thankful to another coin dev if it appears he has helped to increase MintCoin's security.

For now, a new wallet is available and this is a mandatory update!
https://mega.co.nz/#!YI4DETrC!0Cy_PFqWkLF52Ic_Hoo-5v_oyUGWa2R4dcIvlX1S2H0
hero member
Activity: 700
Merit: 500
Sheesh. Wish I saw this thread when it was first posted. For someone running around MINT & BC thread, I'm still missing info.  Undecided
sr. member
Activity: 364
Merit: 250
Is there a projected release date or is it totally experimental? 

Hopefully testnet within 2-5 months or so, then mainchain launch after the testnet seems stable.

Interesting. Thanks for the info!!! Cool
legendary
Activity: 1484
Merit: 1005
Is there a projected release date or is it totally experimental? 

Hopefully testnet within 2-5 months or so, then mainchain launch after the testnet seems stable.
sr. member
Activity: 364
Merit: 250
Hi Tacotime, thanks for the information! I notice you have an ad in your signature that describes a PoS/PoW hybrid.

Have you been able to resolve the issue with that coin?

It's a very different system; basically PoS miners vote on every PoW block to verify the contents, and PoW blocks are validated one block at a time.  PoS miners are given complete control over the contents of PoW blocks and whether or not the PoW miner gets rewards.

This is a *really* experimental incentives system and it might do crazy things yet.  The Bitcoin core devs I've talked to are wary of it doing things I haven't predicted.  Additionally, it relies heavily on PoW (which I think is a good and reasonably fair distribution system).  But it does not have the "nothing at stake" forking issue.

It's more comparable to a blockchain with "two factor authentication" for every PoW block, to ensure that miners aren't putting weird transactions into the network or are simply not including transactions.
Is there a projected release date or is it totally experimental? 
hero member
Activity: 868
Merit: 1000
I've been a MINT investor from the start. go most on my MINT at 8

today i told them I sold half my stake and keeping it BTC. first thing i thought was just stick it in blackcoin.

but from what ive seen fromthe exchanges market has become the last 2 months i'm just sticking with BTC.


i wished they was a bigger response from MINT people.



people know i never bash MINT, but we have to address issues like this.
legendary
Activity: 1484
Merit: 1005
Hi Tacotime, thanks for the information! I notice you have an ad in your signature that describes a PoS/PoW hybrid.

Have you been able to resolve the issue with that coin?

It's a very different system; basically PoS miners vote on every PoW block to verify the contents, and PoW blocks are validated one block at a time.  PoS miners are given complete control over the contents of PoW blocks and whether or not the PoW miner gets rewards.

This is a *really* experimental incentives system and it might do crazy things yet.  The Bitcoin core devs I've talked to are wary of it doing things I haven't predicted.  Additionally, it relies heavily on PoW (which I think is a good and reasonably fair distribution system).  But it does not have the "nothing at stake" forking issue.

It's more comparable to a blockchain with "two factor authentication" for every PoW block, to ensure that miners aren't putting weird transactions into the network or are simply not including transactions.
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