51% Attacks and proof of stake

I know one shouldn’t read the trollbox on btc-e (and now cryptocoincharts.info has one too) but today they were talking about planning 51% attacks against several of the altcoins to destroy them. Will PPC and it’s clones be more resistant to this due to proof of stake blocks?

I have never seen a clear answer on this but after some research here is my conclusion:
First of let’s look at what such attack would allow us to do:
so in reference to the above we are trying to prevent others from spending, mining and we are double spending our coins. In order to make this happen we would need to ensure that we control PoW & PoS. On the PoW side we need to control 51% of the hashing rate (easy to do now) but on the PoS side we would have to ensure that we can continue to submit stakes that have coin age higher that anyone else on the network. So controlling 51% of the coins is not enough, you would have to have them spread over many accounts and each one would have to have coin age greater than anyone else on the network. So in conclusion I believe it is very hard or nearly impossible to do the 51% attack, but I would love for Sunny to explain the inner workings of the protocol so we would have a clear picture of how this works.

Well it looks like feathercoin has been attacked and they’re trying to figure out if there’s anything they can do about it after the fact. http://forum.feathercoin.com/index.php?topic=853.120

That is some VERY interesting reading and a caution to all the scrypt coin forks out there… Feathercoin had a BIG hashrate and now someone has more than 51% of it… I think this will be a sign of things to come… good thing PPC can not really be affected by this with its POS :slight_smile:

Controlling 51% of hashing power in ppcoin network does not get you direct control of block chain, as I explain in the recent weekly update. You need to control proof-of-stake in order to control block chain. Of course if you have that kind of hashing power you probably can accumulate quite a sum of coins but it still require some patience.

Currently block chain is further protected via checkpointing on top of proof-of-stake.

Just wanted to give the direct link to the weekly update since things get buried so quick on bitcointalk https://bitcointalk.org/index.php?topic=114994.msg2432795#msg2432795