There are tons and tons of much smaller coins, that can be attacked for very cheap, and yet attacks are still very rare.
IMO, this is because double spends just aren't a very good idea. If you tried to steal money from an exchange, everyone would know it was you doing the attack, and then they wouldn't accept your money in the future, or maybe you'd just go to jail instead.
Also, the network is not static. If there is lots of hashpower sitting unused, maybe that hashpower would turn in to defend against an attack.
More people have something to lose from a successful attack, and thus could be motivated to defend when an attack happens.
So either PoW has a security hole related to dormant ASICs or it’s useless. Either way it’s not a good look.
If someone owns 10s of millions of dollars worth of miners that are temporarily turned off, do you think this entity would want an attack to succeed?
No. They'd want to protect their future investment in mining equipment. They might just turn that hashpower back in, if an attack was in progress, and take a temporary loss to fight off a temporary attack.
Even the threat of a big player coming in to prevent an attack would make the risk of attacking way to high.
We saw this happen recently when someone tried to attack the Bitcoin Cash network. Defending miners temporarily turned on their hashpower to stop any attacks. And it worked.
Well that depends on how much they're holding and how deep they are in the hole at the given time.
> No. They'd want to protect their future investment in mining equipment.
Unless they were in financial trouble and an attack would get them some cash, fast. The sort of financial trouble that can happen when a company invests, say, millions and millions of dollars into now-unprofitable hardware.
The network is not static. It doesn't matter if one miner wants to make a quick buck, because the defenders have more to lose, and would spin up defending POW if needed.
It absolutely can be in the rational self interest of such players. Relying on other dormant capacity to come up in defence seems fanciful at best.
PoW provides some amount of security but in order to pull off a double-spend you have to not only gain majority hashrate, but also somehow actually spend/cash-out both 'copies' of your coins. This carries substantial risk as you first have to be long those coins (not smart when you are attacking the network). Then convince exchanges to convert both 'copies' while hoping they don't have systems that notice the massive increase in hash-rate nor the unexpected fork you are creating.
Simply shorting a coin, then attacking as more of a DoS may be more feasible but still carries risk as a successful defense could positively affect price.
If they can be attacked cheaply, then by definition there's not much money to gain from doing that.
If you try raiding a market the trade will dry up as traders won't want to come where they may be attacked and trading with people who attack traders is bad for business given the precedents it establish for property rights. Essentially even if you could seize it all it would be worth a fraction of the value because nobody wants to give their goods/money to 'dicks who steal stuff from traders' for the same reason you don't go to barbecues with cannibals. This is one way that markets and trade help promote peace - war becomes a losing move and ones who anger others less are better resourced
If they want to take everything by force you need to seize the goods and means of production themselves - which also highlights why communist countries have had terrible economies - in addition to all of the economic fallacies. Expropriation scares people off.
Come to think of it this is something that has bitten Haiti with its history and highlights the amorality of the effect. Slaves suffered under conditions so brutal that the slave population was sustained through importation instead of reproduction, greed and economic forces caused slaves to vastly outnumber the masters, and machetes were indispensable tools for sugar plantations. While their grievance was justified they were pretty much embargoed pariahs as a result.
The point being that these phenomenon aren't moral or immoral in themselves and are something that should be kept in mind by all actors.
That's a relevant threat to every coin that can use the Bitcoin ASICs. And probably will even happen to others before hitting BTC itself.
If you can flip a switch and 10x the hashrate of a network, all under your control, and you don’t care about killing the chain in your attack, it may be a perfect exit for you if you no longer want to play the mining game.
There’s actually a mining pool doing something like this on smaller PoW bitcoins https://sharkpool.cash (not associated, just think it’s interesting)
> In sum, we strongly believe that it's beneficial to preserve our ASIC resistance. Therefore, we will perform an emergency hard fork to curb any potential threat from ASICs if needed. Furthermore, in order to maintain its goal of decentralization and to provide a deterrent for ASIC development and to protect against unknown or undetectable ASIC development, the Monero team proposes modifying the Cryptonight PoW hash every scheduled fork, twice a year.
[1] https://ww.getmonero.org/2018/02/11/PoW-change-and-key-reuse...
In practice bitcoin is somewhat resistant to large changes or forks, most anyone who would consider any type of alteration to the existing implementation forked off with bitcoin cash for a relatively minor change (block size). That self selection has left a staunchly "traditionalist" majority in the remaining bitcoin community.