Quote from: Brangdon on September 23, 2014, 07:07:11 PM

Quote from: hbadger on September 21, 2014, 01:44:40 AM

Quote from: SlipperySlope on September 14, 2014, 04:00:47 PM

To my knowledge, no proof-of-stake coin has been compromised in a 51% attack

Peercoin has been successfully attacked. The reason these PoS coins are still up and running today is because they either use checkpoints (which makes them 100% centralized and pointless, which is the case of Peercoin), or they are continually making changes which makes attacking them annoying or hard, but is just another form of centralization (they depend on the continuous updates that everyone must accept blindly, as opposed to a stable protocol that rarely changes. Someone compared this to the whack-a-mole game).

Nxt doesn't use checkpoints. Although it adds features fairly often, its core model doesn't change often and new features don't make it harder to attack. Even if they did, I don't see how that would affect mounting a 51% attack. Getting to control 51% of Nxt would be implausibly difficult because of the difficulty in acquiring that many coins.

So you have already forgotten that one time when a hacker stole 5% of all the coins, and with that, 5% of all the hashing power?

And I don't see what's so "implausible" about buying half of the coins when the market cap is so small. Did you know that you don't even need to own the coins to perform the attack? You just need to have owned them at some point, and begin your forks there. With PoW at least the attacker will have trouble recovering the costs of his mining gear which will become obsolete. With PoS that cost doesn't exist. The attacker can sell all his coins and then start the attack.

See what Gregory Maxwell (nullc) thinks about PoS:

https://www.reddit.com/r/Bitcoin/comments/1uoq6e/what_do_you_guys_think_of_proof_of_stake_mining/cek8epc?context=2

https://news.ycombinator.com/item?id=6798997