Some individuals have expressed the opinion {that a} profitable double-spend assault would invalidate Bitcoin as a know-how, and thus undermine the worth of all Bitcoins (together with the attacker’s), making an assault an unwinnable state of affairs.
The “assault undermines the community” assumption is commonly used to justify why a rational actor would by no means try an assault.
Bitcoin, being a public ledger, makes it very straightforward to detect if somebody carried out a double spend assault. And we’d know based mostly on the size of the re-org whether or not or not the attacker had over 50% of the hashpower (per the whitepaper, a >=6 block re-org signifies a 51% assault with excessive certainty.)
My thought is that if my node detected a big re-org and double spend inside that re-org, I might not settle for fee related to the double spender. If his id 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 id was not publicly recognized, his Bitcoins are nonetheless tied to the assault, and no one ought to just accept them for a similar motive.
However on the opposite aspect 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. I can really settle for Bitcoins from everybody apart from the attacker with an excellent larger degree of confidence than I may earlier than!
Would this create a state of affairs the place the attacker has successfully burnt his personal cash whereas concurrently rising the trustworthiness of all different cash?
Or stated one other manner: is it legitimate that we shouldn’t have to imagine a 51% assault would undermine your entire community’s worth to conclude that it might nonetheless be self-undermining for the attacker?