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> Isn't relying on IP diversity as a measure of attack difficulty a bad assumption in the first place? If an attacker has access to the cable outside my home, t

> Isn't relying on IP diversity as a measure of attack difficulty a bad assumption in the first place? If an attacker has access to the cable outside my home, then they can pretend to control as many IPs as they want. If an attacker has access to the cable outside your home they have already won, it's game over. >It seems to me that the most reliable defense against eclipse attacks is to just compare the block rate of the longest chain we know about to the historical average. If the block rate is roughly normal, then either we're seeing the real longest chain, or an attacker has acquired nearly 50% of hash power, which is unlikely. Block creation have high variance. Over short periods of time, say a few hours no blocks being announced is fairly common. Over long periods of time how do you know the mining power has not decreased or increased at a slow rate than your person prediction. >The same idea works with proof of stake -- if the participation rate drops substantially below the historical average, we're probably not seeing the main chain, and we shouldn't consider anything final until the participation rate return to normal. Interesting you can design PoS systems such that if not a quorum of stake is online, no new blocks are created. Algorand has some very neat properties in this regard.

dlubarov 9y ago
> If an attacker has access to the cable outside your home they have already won, it's game over. Not if I'm looking at the block times or PoS participation rates. The attacker can feed me their own fork while preventing me from seeing the actual highest-difficulty chain, but their fork will be suspiciously weak, so I'll know not to trust it. > Block creation have high variance. Over short periods of time, say a few hours no blocks being announced is fairly common. Over long periods of time how do you know the mining power has not decreased or increased at a slow rate than your person prediction. Yeah; with Bitcoin you would need to wait several hours to get a good estimate of hash power. With more granular blockchains like Ethereum you could get a good estimate more quickly.
- EthanHeilman 9y ago
  >Not if I'm looking at the block times or PoS participation rates. The attacker can feed me their own fork while preventing me from seeing the actual highest-difficulty chain, but their fork will be suspiciously weak, so I'll know not to trust it. Would be really interested to read a paper that invents a confirmation sureness metric based on distances between block times which takes into account eclipse attacks.

dlubarov 9y ago

> If an attacker has access to the cable outside your home they have already won, it's game over. Not if I'm looking at the block times or PoS participation rates. The attacker can feed me their own fork while preventing me from seeing the actual highest-difficulty chain, but their fork will be suspiciously weak, so I'll know not to trust it. > Block creation have high variance. Over short periods of time, say a few hours no blocks being announced is fairly common. Over long periods of time how do you know the mining power has not decreased or increased at a slow rate than your person prediction. Yeah; with Bitcoin you would need to wait several hours to get a good estimate of hash power. With more granular blockchains like Ethereum you could get a good estimate more quickly.

EthanHeilman 9y ago
>Not if I'm looking at the block times or PoS participation rates. The attacker can feed me their own fork while preventing me from seeing the actual highest-difficulty chain, but their fork will be suspiciously weak, so I'll know not to trust it. Would be really interested to read a paper that invents a confirmation sureness metric based on distances between block times which takes into account eclipse attacks.