No network wide hashrate stat could ever be as accurate as a pool-wide hashrate.

You can't sum all pool hashrates to get the total because of solo miners, private pools, lucky cpu miners, etc.

As far as how you objectively define the right time in a way which is not controlled by a single entity: https://en.wikipedia.org/wiki/Coordinated_Universal_Time and https://en.wikipedia.org/wiki/International_Atomic_Time


So, 200 points of failure, and 50 trusted entities.  And I think we'd discover it pretty quickly if someone managed to hack into all the atomic clocks in the world and mess with their clocks.

As far as how you distribute that time, NTP does not have a single point of failure, nor is it controlled by a single trusted entity.

If two blocks arrive within 5 seconds of each other, choose the one with the more accurate time.  Where's the single point of failure?  Where's the single trusted entity?  What's the attack scenario in the first place?  Worst case scenario the fix is imperfect; it doesn't introduce any new vulnerabilities.  If the two blocks don't arrive within 5 seconds of each other, everything goes along as normally.

And yes, NTP isn't perfect.  There are security enhancements from the old days of NTP (including from the time when Satoshi mentioned it in the code as a future improvement), though, and even more that can be made.

When two blocks arrive within 2 seconds of each other, and one is timestamped 2 seconds ago, and the other is timestamped 2 minutes ago, you build on the one with the more accurate timestamp, because it's much less likely that that's the one which is employing "selfish mining" or whatever you want to call it.  It's not a perfect solution, but it's much better than what we have now.


That's a start, but NTP accuracy is much better than "a few minutes".  Hell, a clock synced via NTP once per day is almost certainly going to be a whole lot more accurate than "a few minutes".  We can't close the gap completely.  But being able to delay a block by only a few seconds makes an attack a lot less likely to be successful than if you can delay a block by a few minutes.

"Good faithed" miners should be able to agree on the current time within a few seconds.  There's no good excuse for a miner's clock being off by dozens of seconds.

I get your point. Still, it would be relying on data external to the blockchain; and I believe it would be difficult to convince the devs of that.

Also, there is a whole problem of it being "unveriefiable"; that is, in case of a blockchain reorg, nodes would have to accept new "old" blocks, and there is no way to prove that their timestamp is true. However, that is a minor problem, because what we want is a fix for otherwise equally valid topmost block.

Also, the current rules is essentially "undefined behavior"; it says to miners to mine on the first they recieved. However, miners may very well choose to accept the most accurate block, and it would not fork the chain, so they are totally free to choose what they want.

I never realized that. Thank you. I guess I assumed it was the block with the highest value (transactions) or some other tiebreak. So a miner may collect 2-3 blocks found at the same time, but will keep working on the one they heard about first. As soon as someone finds a 2nd block, the one they were working on becomes the "real" block since they have a longer chain and the other blocks are now orphaned.

If two miners working on different blocks also find 2nd blocks at the same time, they keep mining separate chains until someone first finds a 3rd block for one of those two chains?

Thanks for the education.

No, the current rule is really "You mine on the first topmost valid block you recieved", which means three things can happen:
a) You find another block, you broadcast it to the network; it becomes the longest chain.
b) Somebody else finds another block after the block you were working on, it becomes the longest chain and you start mining on that block.
c) Somebody else finds another block on top of another block as equally valid as the one you were working on, you discard your block and accept that chain as the new longest, and mine on top of it.

And yes, in the unlikely case another block was found simultaneously on both chains, both of them would continue to coexist.

But it must be noted that "simulteneaously" is relative here. Two blocks cannot be found at the exact same time. However, accounting network latency, it takes about 1 min for all the nodes to be aware of a new block, in that timeframe, if another block is found, some part of the network may hear about that other block first.

Finally, it must be be noted that work spent on those "alternate" chain is completely lost. Once a block is orphaned, nobody can claim it's reward. And since a potentially large fraction of the network spent time mining on blocks that were, ultimately, discarded, the apparent hashrate of the longest chain is diminished, which means, slower confirmations, and difficulty decrease.

My apologies for contributing to that. I hate it when it happens on other threads.

finally.

So, NMC payouts would be next?

SCNR 

Meh, use chicken blood, much cheaper and works, too ^^

But a guy on IRC was selling it super cheap... 10000 NMC per liter.