5 ms·
You only need to spend as much as the miners already are doing. With proof of work, if it is feasible to run, it is feasible to attack. And vice versa, if it is
by tveita 10y ago
You only need to spend as much as the miners already are doing. With proof of work, if it is feasible to run, it is feasible to attack. And vice versa, if it is not feasible to attack, it is probably not cost effective to run.
Bitcoin may be wasting enough electricity to put it out of reach of small-time attackers, but a nation adversary could outspend it for as long as necessary.
- smokeyj 10y agoBut what does the attack get you? Sure you could mine empty blocks and double spend, but that would hardly be worth the investment. Besides, if payment processors detect the hashing rate doubling overnight they can simply require more confirmations. If a nation state invested in permanently disabling bitcoin that would require a big investment in ASIC's, at which point I imagine a bitcoin fork would be introduced with a slightly different PoW, but that's just speculation.
- tveita 10y ago> a bitcoin fork would be introduced with a slightly different PoW And then what? Either you're falling back to mining on CPUs or GPUs, which the attacker would presumably have a large amount of, or you're manufacturing a new batch of ASICs, which is just as expensive for you as for an attacker. The point remains that an attacker can win by spending only slightly more money than the defender. Whether that's "worth the investment" is up to each individual actor, apparently it hasn't been yet.
- jerf 10y ago"The point remains that an attacker can win by spending only slightly more money than the defender." It's actually only slightly more than the sum of the defenders (assuming as we are for the sake of argument that everyone is buying efficiently). If what you said was true BitCoin wouldn't even have gotten to where it is now.