Quote from: coinsolidation on June 27, 2014, 05:19:45 PM

Quote from: ChuckOne on June 27, 2014, 05:01:39 PM

What are the costs of performing a 51%-attack in
1) PoW?
2) PoS?

Anyone?

1) Hundreds of Millions.
2) Theoretically nothing, if you discount checkpoints. with checkpoints it's hard.

But then there's the social 51% attack where a tiny majority hold a massive percentage of the currency. When this occurs the market is open to extensive manipulation for the benefit of the few, as with real world economics (the 1%).

NXT is a good example of the social 51% attack, the top 33 accounts hold 51% between them. The top 50 accounts hold 61.2%. I'm quite sure the top 1% of accounts (400 ish) hold almost everything, with the other 99% playing with spare change. source

I think that's why you see so many NXT shills trying to ram it down everybodies throats on this forum.

First of all, Nxt is somewhat resistant to 90% attack of the underlying system. Because in order to build the longest chain, a 90% attacker would have to perform a whole lot of hashes to figure out which chain was the longest one in advance, that also excluded the blocks of all other forgers.

We're talking 10^100 hashes or something in that range... probably much, much higher. Those would have to be done within about 12 hours time. Considering that it would take the entire Bitcoin network, by far the biggest source of hashing power, approximately 2^75 years to calculate that.. I'm not all that worried.

Certainly, the more decentralized the better when it comes to crashing the price but.. if you consider Nxt like a stock, it is much more decentralized than that of any big company out there that I know of.

In Bitcoin, 2 or 3 guys could gang up and take down Bitcoin or hold it hostage when it gets big enough.. imagine once Bitcoin grew to be US dollar sized and 3 guys could threaten to take down the network(or be hacked or a terrorist organization threatens them by saying they'll kill their kids, or whatever) in Nxt, you'd need 33 accounts to do so? And even then, you'd knock out some of Nxt's cooler features but the main network features could still continue to run even against that attack. And not only that but it is getting better distributed with time, I think the constant downward pressure on the price is proof of that as those with big accounts are continuing to cash out over time.

In Ripple's case, yeah I stayed away from Ripple once I heard that the company held onto 90+% of the stock.. but in Nxt's case, I just don't see it as that big of a risk.