Some individuals have expressed the opinion {that a} profitable double-spend assault would invalidate Bitcoin as a expertise, and thus undermine the worth of all Bitcoins (together with the attacker’s), making an assault an unwinnable state of affairs.
That doesn’t appear cheap to me. We have now seen doublespends on different networks and people networks persevering with to function later. It might absolutely influence the worth of Bitcoin, nevertheless it appears absurd that the brand new worth would instantly be zero. Most individuals wouldn’t even catch on to the occasions for hours or days.
My thought is that if my node detected a big re-org and double spend inside that re-org, I’d not settle for fee related to the double spender. If his identification was publicly recognized, no one would settle for his Bitcoins as a result of they know they’re liable to be double spent. If his identification was not publicly recognized, his Bitcoins are nonetheless tied to the assault, and no one ought to simply accept them for a similar cause.
Relying on how the attacker chosen transactions of their blocks, there is perhaps one thing on the order of 24 000 transactions in six blocks that turn out to be unconfirmed if the attacker merely doesn’t embrace any transactions within the alternative blocks. Whereas it could be doable to discover a single or few transactions with excessive worth that resolve otherwise, it could be fuzzy and non-obvious for a quantity extra. I’m not satisfied this can be a sensible method.
However on the opposite facet of the coin… Now, I do know for a reality that every one different Bitcoins not related to the attacker can’t be double-spent, as a result of by definition just one entity can have greater than 50% of the hash energy at a given time.
Assuming that the attacker solely contains their very own transactions, the senders of ~24 000 transactions can be within the place of having the ability to reissue their very own transactions. It’s not clear in any respect to me why somebody attacking the blockchain gives extra confidence to the actions of different customers.
Would this create a state of affairs the place the attacker has successfully burnt his personal cash whereas concurrently growing the trustworthiness of all different cash?
No, by no means.
Or mentioned one other approach: is it legitimate that we don’t have to imagine a 51% assault would undermine your entire community’s worth to conclude that it could nonetheless be self-undermining for the attacker?
No, by all chance, the attacker would instantly commerce out of Bitcoin in the event that they have been fearful in regards to the assault severely impacting Bitcoin’s worth. They may not be capable to commerce a few of the cash that have been concerned within the assault, however they might brief Bitcoin in a future commerce or a minimum of commerce all their different Bitcoin holdings. The attacker may then even commerce again in on the dip brought on by their assault’s injury to Bitcoin’s worth and earn extra worth on the restoration. I don’t suppose this argument stands as much as scrutiny.
