Quote from: yj1190590 on January 29, 2019, 04:18:07 AM

Quote from: monsterer2 on January 28, 2019, 07:42:59 PM

Don't forget about bootstrapping nodes - this attack is also a bootstrap poisoning attack, as well as an attack against already up to date nodes and bootstrapping nodes cannot use your re-org depth limit.

Bootsrap attack may be a common problem of all chains with finalization. Let's talk about the difficulty and the impact of launching a successful history bootsrap-poinsoning attack in our system.

First, you have to find a history point where there are enough empty accounts that had more stakes than the average total online stakes after that history point.

That isn't true for bootstrap poisoning - as far as any bootstrapping node knows, there is no history available *after* their currently syncing block. A bootstrapping node will accept any valid data as canon, whereas an online node would be able to discard old forks because it has a memory of the real chain.

Moreover, I would say bootstrap poisoning is a problem for all coins which have the NaS problem. 'Finalization' is not a well defined term.

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As the example I gave, the users who sold their empty accounts to the attacker are actually risking their assets (if the attacker succeeds ,their current assets A' and B' will become useless.) for a short-term profit which is the cost of the attack. And that risk cost should not be low enough for one to bear. At least he can't attack constantly, that makes the influence of the bootstrap poisoning attack limited (maybe a fork with a few victims, which won't last long).

The users who sold their now empty private keys to the attacker risk nothing. They have long since profited by cashing out.