NYSE launches a Bitcoin index
americasmarkets.usatoday.com
americasmarkets.usatoday.com
Methodology: https://www.nyse.com/publicdocs/nyse/indices/NYSE_Bitcoin_In...
It's apparently calculated once a day within two hours of 4 PM UK time (GMT +1) and relies on one source: Coinbase Exchange.
The methodology is scheduled to be reviewed four times a year.
If difficultly is stable then what matters is how efficiently you can mine, i.e. how many bitcoins you can mine relative to how much electricity you spend.
Well if you control say a third of the pool, then you can obviously capture a third of the bitcoins and spend a third of the electricity.
Or, you can mine alternate difficultly periods.
When you mine, the next period the difficulty will be 1. Then you chose not to mine and the pool loses 1/3 of the hashing power, so next round the difficulty will be 2/3. Then it adjusts back and it will be 1 again.
The result is that you get to mine at a lower difficulty than the rest of the population. The difficulty increases from your hashing is paid for by everyone else and not by you, then you get the enjoy the reduced difficulty from others not mining as fast.
This becomes de-stabilising because the rational thing when faced with this is to join you on only mining the easier periods which further makes the problem worse.
This effect starts happening with any amount of hashing power, even with 1% hashing rate you would see a small efficiency improvement by mining alternate difficulty periods.
Plenty of systems work fine like this in nature - it's pretty much a textbook predator/prey dynamic, and yet carnivorous life has been going on for several hundred million years on Earth. It would be a problem if the dynamic was for the number of miners to drop to zero or explode to infinity instead, but this is a negative-feedback cycle, not a positive-feedback one.
You are wrong as characterising this as negative-feedback, this is positive feedback because if you are presented with a situation where in even "weeks" (which now last 6 days) the difficulty is 10% less than odd weeks (which now last 8 days), then you will join mining only the easy weeks which further feedsback to more distortion.
edit to add: I realise the adjustment period is not aimed to be 7 days, this is for easier illustration.
The question is what is the "activation energy" required to initiate the oscillations. Is a large miner (how large?) likely to attempt this knowing the ultimate outcome?
And more importantly, can it be fixed? The protocol isn't set in stone.
This attack can be pulled off in economically satisfying way only then your electricity costs dominate your overall costs, i.e. you do not pay rent, wages etc. And this is false.
Given miner's situation (he pays wages and rent) to use this attack effectively miner needs to represent significant part of hashing power of network. This means that his stakes are high and engaging in destructive behavior may undermine reputation of Bitcoin as network, BTC price and ultimately miner's own business.
In case lower scale attack (manipulation of hashing power of a pool) pool and his operators are there to punish such behavior.
EDIT: language
Do you mean alternate difficulty periods, as opposed to alternate blocks (whch would mean switching on/off every 10 minutes and would not affect the difficulty significantly.
You can't rapidly jump between difficulties like that.
It's about the fact that you mine more efficiently not suddenly mining a lot more bitcoin. (You actually mine fewer blocks overall but at a larger reduction in running time costs than the reduction in mining.)
Mining "more bitcoin" or mining "more efficiently" don't matter. What matters is the speed at which 2016 blocks are produced network-wide.
What happens is that in higher difficulty periods your competitors who keep running constantly are making 1800 coins each. When the hash rate drops and you come on everyone gets 1200 coins each. Your expected revenue becomes 600 coins/period. The result of your strategy relative to just running constantly is halving revenue.
The only variance introduced is the speed at which new blocks are generated in each period.
The important point is that an attacker could use this just to wreck the cryptocurrency in question, although they may simply buy more coins at the lower price and profit from any rebound.
Everyone mines at the same difficulty. If you choose not to mine for a period (and the difficulty adjusts to a lower level), you're just encouraging more miners to fill your void - your absence represents new opportunity for miners who might not have been profitable at the higher/original difficulty.
Even if new mining doesn't increase difficulty to the original level, you're always mining at the same difficulty as the rest of the population, so your supposed gain is everyone else's gain, meaning it's effectively non-existent.
In other words, just because you can affect difficulty by temporarily choosing not to mine, your absence (and lower difficulty) does not decrease participation of other miners; if anything, it will encourage more mining and ultimately cause the difficulty to increase for everyone.
It's one of the quirks of capitalism that markets remain efficient only to the extent that people believe that they're inefficient, and liquid only to the extent that people are misinformed about an asset's value. To see why, imagine a perfectly efficient asset market with perfect information, where the goal of every participant is to maximize their financial returns.
In such a market, all participants know everything that all other participants do, they know that all other participants know everything they do, and they can transact instantaneously without cost. Prices in this market converge instantly upon the "true" value, which can be agreed upon by all market partipants because of their omniscience.
Such a market has zero liquidity. Why would anyone transact if they know that a security already has the correct value? For there to be profit potential, the person who sells to you must be misinformed about the security's true value, which contradicts the assumption of omniscience.
The interesting thing is that the more market participants believe in the market's efficiency, the more inefficient it becomes. With little incentive to do their own research (why bother, when the current price reflects more information than they could possibly amass?), the underlying fundamental value of the asset can drift further from the consensus price without anyone noticing. This increases the profit potential for people who assume that they know better than everyone else. Eventually, a few of them get rich, the consensus breaks down, lots of people lose their shirts, and the market becomes efficient again.
The result is the business cycle. Periods where people believe in the market's efficiency are bubbles (when the consensus price is above the true value) and panics (when the consensus price is below the true value). Periods when they don't are crises, where the prevailing momentum swings but this change in opinion is unevenly distributed.
Lots of things fundamental to the modern world are unstable. The whole concept of a financial asset is one of them. I can think of a number of individual industries that have an unstable dynamic, but I'm not going to name them because I believe there's profit potential in them. Public opinion is yet another one.
Or is there something I'm missing?
It's an index from a company that maintains over 2200 indices at the moment.
Lets say I make 100 pieces of red paper but this time I say each piece of paper represents 1/100th of an index fund that tracks the cost of the blue paper. Also whoever buys a red paper from me has to pay me annual fund management fees.
You're telling me you want to buy these pieces of paper that ALREADY track a "currency" that is quite sketchy in nature? If you want to gamble your money, gamble the right way, buy the blue paper, or in other words just buy bitcoin straight up.
It's also debatable if you've stopped beating your wife or are in a loving marriage with her. Hopefully you see what we both did there.
Context: http://en.wikipedia.org/wiki/Mu_%28negative%29
Personally, I don't consider Bitcoin a currency. It's more than that.
I'm curious to hear why you think it's more then "currency." Personally I think you can't even call it a currency yet.... Though this may change down the road.
Bitcoin provides features of currency, but does so with a nod to identity management as access is limited to those with the keys. This means cryptocurrencies could give way to federation, which is payments + identity + some standard. The problem cloud continues to disrupt everything in sight - including traditional 'currency'.
You just described fiat currency. Just change blue to green. (in the US - others than many other colors, so pretty). Bitcoin is backed by a cryptographic standard. The USD is backed by the government and a military force. Both are seen as valuable by someone. Both have little or no true valuable items behind them, other than confidence. One, the government and the guns, the other, the anti-counterfeit nature and provability via the global ledger.
Bitcoin is still new and thus still speculative. Being backed by cryptography doesn't mean shit. It just means you can't copy it. So what? It still holds zero intrinsic value. Sure the dollar holds no intrinsic value either. But why the dollar vs bitcoin vs some other cryptographic currency I pull out of my ass? The difference is culture and tradition, the dollar has tons, bitcoin... not as much. This is why the price of bitcoin fluctuates so wildly. Most people don't buy bitcoin to use as currency... the entire BC market is like a gambling house where people try to buy and sell paper from each other.
Don't get me wrong, I'm not saying don't buy bitcoin or don't support it... I'm just saying to be aware of what it currently is, and what it may transform into in the future...
The government has control through the legal system which is the ultimate recourse for dispute over payment of goods, and it exercises this control by assessing damages, when a dispute is resolved through the courts, in US dollars.
The main difference is inflating the money supply. The government cannot control the supply of bitcoin the way they do with green dollars.
Bitcoin is currency.
What it is not is legal tender.
Courts in the US have the legal power to enforce payment in bitcoin or Euros or chickens or hours of service or any other form now. They also have well-established rules that they only do so in manners other than the legal-tender currency established by the government in certain exceptional cases.
Most people will not accept bitcoin as a medium of exchange. I cannot go to my local grocery store and buy something with bitcoin. I can, however by something with dollars. Thus bitcoin is not yet a currency.
Decades of culture and tradition have molded the dollar into something different from people just selling paper. Bitcoin is not yet such a thing.