Some folks 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 scenario.
That doesn’t appear affordable to me. We’ve got seen doublespends on different networks and people networks persevering with to function later. It could 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 might not settle for cost related to the double spender. If his identification was publicly identified, no person would settle for his Bitcoins as a result of they know they’re liable to be double spent. If his identification was not publicly identified, his Bitcoins are nonetheless tied to the assault, and no person ought to just accept them for a similar motive.
Relying on how the attacker chosen transactions of their blocks, there could be one thing on the order of 24 000 transactions that develop into unconfirmed if the attacker merely doesn’t embrace any transactions within the substitute blocks. Whereas it might be potential to discover a single or few transactions with excessive worth that resolve in another way, it might be fuzzy and non-obvious for a quantity extra. I’m not satisfied it is a sensible strategy.
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 consists of their very own transactions, the senders of ~24 000 transactions can be within the place of with the ability to reissue their very own transactions. It’s not clear in any respect to me why somebody attacking the blockchain offers extra confidence to the actions of different customers.
Would this create a scenario the place the attacker has successfully burnt his personal cash whereas concurrently rising the trustworthiness of all different cash?
No, in no way.
Or mentioned one other approach: is it legitimate that we do not need to imagine a 51% assault would undermine your complete community’s worth to conclude that it might nonetheless be self-undermining for the attacker?
No, by all probability, the attacker would instantly commerce out of Bitcoin in the event that they have been anxious concerning the assault severely impacting Bitcoin’s worth. They may not be capable of commerce a few of the cash that have been concerned within the assault, however they may brief Bitcoin in a future commerce or not less than commerce all their different Bitcoin holdings. The attacker might then even commerce again in on the dip attributable to their assault’s harm to Bitcoin’s worth and earn extra worth on the restoration. I don’t suppose this argument stands as much as scrutiny.
