Quote from: valarmg on January 17, 2015, 11:01:47 AM

This attack requires a large % of a coin's stakeholders to be stupid enough to trust 'Pirate S+T'. Why don't you call your bank cryptodouble instead of Pirate S+T? I think cryptodouble is a catchier name, might get more suckers. In the accumulation phase, you are 100% operating a ponzi. How do you convince people to invest in the ponzi (I know, tell them it's not a ponzi, you instead intend to attack the currency)?

Explain why you can't do the same with a PoW coin? Just needs the added measure where you buy hashrate with your accumulated funds, but you would require much less funds. What % of bitcoin, what % of litecoin would it take to buy enough hashrate to attack? What % of a PoS coin would it take for you to attack that

What happens if your attack doesn't reduce the value of the coin to zero? Does your attack merely consist of double spending?

All these questions have been answered in the previous page. Additionally, convincing people to invest in a ponzi is just one variation of an attack, other variations include convincing 10 % to deposit their stake in your exchange / bank, or taking 10% loans with many profiles , or simply being a large whale that already has 10% or more as is possible with NxT. Why do you act incredulous when these scenario's are commonplace within the crypto ecosystem?

The wastefulness of PoW is also a form of security because it incentivizes users to merely profit off of a bear raid and other market manipulation tactics rather than attacking the currency with a 51% attack. The difference with PoS you can attack the currency and profit in doing so and with PoW you have to take a large gamble and spend a lot of resources in order to perform a 51% attack.

Quote from: ThomasVeil on January 17, 2015, 11:06:52 AM

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In my attack there is no additional purchase required,

You don't understand your own text. I give up man.

You can start by first educating yourself from what researchers are discussing who are sympathetic towards PoS:

https://github.com/ConsensusResearch/articles-papers/blob/master/multistrategy/multistrategy.pdf

https://blog.ethereum.org/2014/11/25/proof-stake-learned-love-weak-subjectivity/
https://blog.ethereum.org/2014/10/03/slasher-ghost-developments-proof-stake/
https://blog.ethereum.org/2014/07/05/stake/

After you have done this research come back and join the conversation.

Quote from: ThomasVeil on January 17, 2015, 01:34:58 AM

Secondly ... come on guys: I buy 51% of a POS, then I buy again 51% of the value as shorts (well, more - as I want to make profit).

You understand that one doesn't need to invest in any of the currency , or control 51% stake when performing a N@S right?

Quote from: kushti on December 18, 2014, 05:12:37 PM

- we have formally defined nothing-at-stake attack(again, using Buterin's informal definition) and made initial simulations. We haven't included their results in paper as they are seems to be too raw, but I can reveal them here: N@S attack could happens only in short-range, e.g. for within 20 blocks for 10% stake, so with 30 confirmations we haven't observed the successful attack. Also please note the attack has pretty unpredictable nature for attacker, so he can hardly enforce it, even in theory(in practice it's even harder to get it done properly). The correlation with stake size is still the open question, but it's nearly impossible to attack a proof-of-stake currency with "1% stake even" as stated by Buterin

The above applies to NxT and other variations of TaPoS only . Other variations of PoS are susceptible to long-range attacks as well.