Re:Bitcoin Gold Hit by Double Spend Attack, Exchanges Lose M...
by Jommi on Wednesday May 23, 2018 @11:11PM
(#17140784)
You're looking at this as a static _binary_ model, while actually, the 51% attack is heavily dynamic. The profitability of the attack heavily depends on factors that are absolutely dynamic and not publicly available:
- The exchange/betting website not catching onto your scheme
- The volume of the coin being enough to mass sell it and not majorly affect the price
- How fast the community can act in unison against you
Why would you think an enormous amount of hashing power helps? Even with Bitcoin, the actual marginal cost of a 51% attack is quite low. The difficulty is the capital expense of actually connecting to a couple GW of power and finding enough rentable ASICs.
I think this is fundamental. In a proof-of-work scheme, if the mining rewards in whatever time frame is considered a full confirmation are less than the amount of gain available using a 51% attack, then a 51% attack is economical.
ASIC mining during boom time helps mitigate the issue a bit, since the ASICs are worth more if the currency isn’t devalued by 51% attacks, but even Bitcoin will be vulnerable of older, less efficient ASICs start flooding the market, which seems inevitable if the price of BTC stagnates enough.