[DennisP]

VISA is typically around 2000 tx/sec, so it'd only saturate at peak. And anyone with gigabit fiber won't be bothered even at peak. If we reach that traffic level, gigabit will probably be fairly widespread by then.

I don't see how those nefarious miners could succeed, unless they were powerful enough to carry out a 51% attack anyway. Otherwise their secret chain will soon fall behind the public chain.

[sp332]

The fewer miners there are, the easier it is to carry out a 51% attack. And the top miners have much more processing power than the average miner. Just a few of the top ones collaborating could carry it off.

[DennisP]

That's definitely a problem, and it's the reason other projects are working on ASIC-resistant proof-of-work. I just don't see how the method I described would make things any worse.

[sp332]

I'm just pointing out that limiting active miners to people with fast internet connections means there will be fewer of them.

[erok]

This used to be an issue with pools but I don't believe this to be a risk so much anymore.

[sp332]

Why not? Pools are still huge, and at least the "ethical" members of a pool could move their processing power to a different pool. If individuals are bigger than pools now, that means even fewer people have to collude to get 51%.

[darkmighty]

Are there plans/other networks which distribute blockchain storage and mining somehow?

[DennisP]

The Ethereum project has some ideas for making it so each node only has to see a subset of transactions, instead of all of them. It's not an easy problem.

They and a few other projects also hope to pull off a "proof-of-stake" system that mostly does away with mining. Done naively that can be attacked, but there appear to be ways to mitigate the problem. Initially, Ethereum is settling for a proof-of-work algorithm that's more resistant to specialized hardware, so big central miners can't get such an advantage.