Quote from: DaveJones on September 02, 2016, 09:09:18 AM

Sybil attacks can happen in many different ways.

Like rigging the voting on the monthly budgets. If you have, say 600 Masternodes, which one or more of the DASH shills do, then you can just vote for what you want. Or you can just co-ordinate how you want a vote to go with a core group.

Is DASH Sybil resistant? No.

Game over. Close the thread.

First things first : you dont need 600 masternodes to vote for what you want, you just need 1 masternode to vote for what you want.

Secondly : each masternode owner gets 1 vote to cast a yes or no with on budget proposals and the masternode owner can change that vote at anytime to show either approval or disapproval
for that specific budget proposal. There is no rigging of votes possible, if masternodes are not active or unresponsive or do not have their collateral of 1000 Dash anymore, it will not get acknowledged
as masternode anymore by the Dash network and the masternode payments and the ability to vote will stop. There is definetely no vote rigging possible there as it is all formulated in the code.

It is true that the more masternodes people have, the more votes they can cast on budget proposals. Our biggest whale otoh for example has something like 450 masternodes, all bought openly on the market
and can use those votes to either : support the dev team / support desirable proposals / cast down undesirable proposals. That gives this person a lot of power but in the end his votes are still only part of a larger anonymous masternode owners group (450 of 4076), that will decide the outcome of a budget proposal. The combined effort of both Otoh and dev team to push a budget proposal up or down are limited as can been seen in the voting figures :

Most of these budget proposals are from the dev team (babygiraffe, eduffield, kot) and there is 1 from Amanda for her YouTube video as well.
All these budget proposals where dev team and likely otoh himself voted on, have between 20% and 43% support (% of vote). Which means that more then 50% of the masternodes could potentially
further downvote or upvote a budget proposal, this means that dev-team & Otoh combined or each seperately have a limited voting impact. Reach the 50% of the masternode owners
that are currently not voing on budget proposals and you will see the full voting force at work.

Now to get back to Sybil Attacks and Dash resistance to it, it basicly involves two factors : costs and profitability

costs

* buying up enough masternodes (up to 51%) to control any budget proposal is impossible with Dash as there is not enough Dash available anymore to buy that much up as more then 4,079,000 Dash (number of masternodes x 1000 Dash) of 6,706,308 Dash (available supply) is already locked up as collateral for running masternodes and is therefore not available on the market. Leaving only 2,627,308 Dash availabe on the market for buy-up (2627 masternodes).

* each buying up of masternodes to reach a sizeable % (lets say 10% or 20%), will directly impact the price of Dash, shooting it upwards and further increasing the costs for the attacker and has a very very
limited satisfactory outcome for the attacker (see page 1 post 2)

profitability

It will be far more profitable for the attacker to work with the system then against it, it could either :

Buy-up Dash, make the price go up exponentially, still have a very limited damage outcome (see page 1, post 2), massively dump Dash to put temperary down pressure on the price, watch the price self correct at some point (it always does)

or

Buy-up Dash, make the price go up exponentially, still have a very limited damage outcome (see page 1, post 2), enjoy the steady masternode payments (which by the way will rise with any price rise, making it for whales with lot of masternodes actually profitable to focus on making the price rise).