A)
A single delegate can have at most 1 active feed. Only the last feed from each delegate matters if it is published in the last 24 hours.

Ok, so that reduces the discontinuity to when a new delegate gets voted in. Less serious than having discontinuities every block

How exactly do you envision this "counter attack" happening? They're going to bribe all stakeholders to only vote for delegates who don't create blocks?

Same way as you'd do it to them. Use buying power to buy a controlling voting stake - last I heard that was something like 13% of market cap. Then you just vote in a bunch of bad delegates and 'whoops wheres your blockchain'.

No, I think the actually used price feed is the median of all published ones.

Are you sure its not a median of all current feeds to the current delegate?

Yes.
And that is a good thing.

Doesn't that mean that the price feed will change abruptly every block?

Prior to yesterdays 'event', the orderbook on bitrex (the only exchange trading ethercoin) looked like this:


bids                       asks
0.00020    20              0.00030       15
0.00010    10              0.00035       20
0.00005    200             0.08          100

'Market cap' was 0.00030 BTC x 1000000 = 0.15 USD x 1,000,000 = $150,000

This figure is just the best price X coin supply and ignores the fact that the buy side of the book only contains 0.015 BTC.

Then, some fat fingered trader comes along and places a market buy order of value 0.0115 BTC, which eats into the sell side of the book, leaving it looking like this:

bids                       asks
0.00020    20              0.08             100
0.00010    10             
0.00005    200     

Now, the 'market cap' becomes 0.08 BTC X 1000000 = 30 USD x 1,000,000 = $30,000,000

So, 'market cap' increased by 200 times, and yet there was only a buy order of roughly $4.

The mistake here is the market cap valuation using the best price. In markets that are this lacking in liquidity (like all cryptocurrency markets are), it is totally meaningless to calculate the market cap like this. To do it right, you need to clear the available supply against the buy side of the orderbook, aggregated for all market places.

note: these orderbook examples and trade sizes were simplified for illustration purposes.

Cheers, Paul.

I was madly putting in sell orders at 4500 and rebuying at 4300 (which was still 5% above the btc38 price), and I was getting hit instantly on every order I put in on BOTH the buy and sell side, as fast as I could put them in!  It was literally free money, I made 4000 BTS in five minutes just being the market maker on both sides of the spread!  Then it calmed down again and the price went back to tracking btc38.

In my experience market making like that is great... until you get lumbered with a large holding of the wrong sort at the beginning of a strong trend and lose it all the profit again!

I still fail to see how any of this is possible without an outside investment large enough to buy all the mining power in whatever coin the attack is directed against.

You cannot just print currency to fund this, it doesn't make any sense.

You're partly right. I see it in trading, where they compare how 'correlated' two things are. And though I can't do the maths, I do see BTSX is highly correlated to BTC and then other 2.0 vs. just an independent price.

Here's the evidence, and this was a PITA to do, so hope you appreciate it!



These are the overlaid market caps from the last 30 days. NXT is red, BTS is green. Notice the massive positive correlation