Quote from: iamnotback on March 31, 2017, 01:25:41 AM

Decred is based on PoA which is a research paper written by 4 respected computer scientists including Meni Rosenfeld. However, the security has a major flaw which they admit in their equation.

Notice in their example if a whale had 20% of the stake, then assuming 50% of the stake is online and participating then that whale would need more than 8 times the honest hashrate in order to double-spend, i.e. 88.8% of the hashrate (because 8 x 11.2 > 88.8%), where N = 3 is the number of stakeholders that sign each block.

((1/0.2 - 1) × 0.5)³ = 2³ = 8

But notice as a whales' (or colluding whales) percent of the stake climbs towards 50%, the design goes pear shaped and the security collapses:

((1/0.5 - 1) × 0.5)³ = 0.125

Which means you'd only need 12.5% of the hashrate to double-spend. The reason this is so, is because with the control over stake, the attacker can deny to respond to blocks found by the honest miners.

The problem is that to increase the leverage on the side of higher security at low levels of dishonest stake, by increasing N to 3 or greater, this causes the leverage to bite you back at higher levels of dishonest stake as shown above. And it is also damn bad at even lower levels of dishonest stake:

((1/0.33 - 1) × 0.5)³ = 1

Okay that is standard 51% attack but that assumes 50% of the stakeholders are participating in mining! Which isn't going to be likely for any mass adopted coin. Certain all the tokens on the exchanges aren't mining. At 33% participation it goes pear shaped again:

((1/0.33 - 1) × 0.33)³ = 0.29

Actually I am very disappointed that Meni would sign onto work like this. Because when you combine this with selfish-mining strategies on withholding PoW blocks and releasing them late, the security is just horrendous.

This shitcoin is currently seeing a huge rise in price because n00bs don't know how to read a white paper. And thus they don't realize they are buying insecure shit that has no chance whatsoever of being the next big thing.

Its sad actually. Because this shit might continuing going up in price even though it stinks real bad.

You know I am not the most technical person ever, just confirming something, so you need 50% of the tickets, so assuming roughly 50% of the total coin supply is tied up in tickets you need roughly 1/4 of the total coin supply and then you need 12.5% of the hashing power to pull of the attack, is that right?

If so then I don't see it as an issue right now, however, when it becomes less valuable to hold tickets (due to the coin emission rate lowering) resulting in less people staking then maybe I see an issue? Or do you see it as a clear and present danger right now?