If an attacker simulated an Ethereum network, with 1 million validators in it. He has keys to all validators, because the entire thing is his simulation. He simulates several decades, which in real time is probably several hours.
Then he broadcasts his simulated network to the real Ethereum network, and claim his is the real one. All his 1 million validators start communicate with the real validators. Since his network history has more “total attestations”, his network should be the real one according to the chain selection rule.
This is impossible in PoW, because he would need more hash power than all the other miners combined to simulate a “heavier” history. But that is not the case in PoS. I am curious, how does PoS solve this?
You’re essentially describing a long range attack. That is the tradeoff that PoS makes over PoW’s full objectivity, in that a node who comes online for the first time (or after being offline for a while) cannot fully-objectively distinguish between the real fork and an attacker’s fork who simulated years of attestations.
It’s where the term “weak subjectivity” comes into play, you just need a recent state root from a node you trust (be it a friend running a node or a block explorer or whatever) and that’s what will tell your node which fork is the real one, and from there you can just keep following attestations from real validators and the long-range attackers can’t hurt you
Perfect response. Learnt something good today.