Quote from: casascius on December 24, 2011, 03:23:33 AM

The only people that would matter the most are those who are mining ....

what?

I think your understanding of block singing and network validation is flawed. In a 51% attacker miners are irrelivent. The attacker has more hashing power than all legit miners. It isn't an issue of good miners being "confused" and continuing the bad chain. Their actions are utterly irrelivent. The double spend will happen in a matter of seconds or minutes.

The attacker will build a private block chain and not release it until it is sufficiently longer than the good chain. Instantly clients will recognize the logner chain as valid.

The attacker wouldn't care what miners know or think they are irrelevant. What CLIENTS know and think is what matters. If clients are relying on your service attackers would only need to disrupt it (though finger nail pulling or large bank accounts in the Caymans) for seconds. The false chain will be PRE-MINED and bad blocks released in rapid succession which you will sign as valid. Clients accept it and double spends are confirmed as good transactions.

What happens AFTER that is also irrelevant. The damage is already done.

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I would need to BE the adversary, or under the control of the adversary, to sign the wrong block stream. And remember, no one would want or need to subscribe to my service during times of network peace - I'd only be a defensive countermeasure available to those who are actively fighting the attack. Assuming I did a good honest job, others would see the value of making my service redundant, and then the assumption that 11+ other people might be doing the same thing for the good of the network wouldn't seem so silly as someone suggested.

Exactly if necessary you would be under the control of the adversary or simply dead and your keys under their control. Also this concept of a heroic ongoing war between good and evil isn't factually valid. There will be absolutely no warning of a 51% attack until it has already happened. The entire bad chain will hit the network simultaneously and be propogated in a matter of seconds. There will be nothing to fight.