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Comment by awaythrowact | Hacker News Reader

My understanding is, proof of stake is not more secure than proof of work. Reason for PoS are efficiency, speed of transaction, lower gas fees, less environmental impact, etc. (Of course there can be secure PoS, insecure PoS, secure PoW, insecure PoW…)

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Polygon basically checkpoints a spreadsheet onto the eth chain on an interval, but there is no way to guarantee that there weren't any shenanigans between the checkpoints. This is a big improvement over say BSC which does no such thing, but it isn't the security of a true eth L2. Real L2's can prove that their output to L1 is legitimate either through zero knowledge cryptographic proofs (loopring, zksync) or through a game theory fraud check (optimism, arbitrum).

PoS is more secure in general, also PoS and BFT-based cryptocurrencies in periods of network partitions will rather come to a stop instead of allowing safety to be violated (double spending).

Once they stop, they don't start again without external intervention (so you're back to The DAO when it comes to which validators are not Byzantine). PoS is a bet that 1/3 of the staked tokens never, ever fall into the hands of Byzantine actors -- not by purchase, not by theft, and not by DeFi smart contract hacks. That's not a bet I would take.

That’s not true, a good bft protocol will resume once network conditions stabilize.

And how, exactly, will the "network conditions stabilize" if over 1/3 of the votes are malicious, and thus able to prevent the honest voters from ever agreeing on anything ever again? Are you betting that the attacker will just get bored and walk away?

Also, what a confusing choice of words. A distributed system is BFT (or not BFT) regardless of whether or not the underlying message broadcast medium is synchronous/asynchronous, or reliable/unreliable. The "network conditions" being "stable" have no bearing on the voters' ability to reach agreement -- that's solely a function of whether or not f or fewer votes are malicious out of 3f + 1 votes.

I was talking about network conditions, not a threshold of malicious participants (in which case yeah you will have liveness issues).

Your second paragraph is false also. Different BFT systems have different assumptions. Some work in asynchronous settings, some work in semi-synchronous settings, etc.

You should consider rereading Leslie Lamport's original paper. BFT is a property of corrupt votes, not the network. You keep trying to make it about the network. Like, if you want to have a conversation about how the network can influence the system's fault tolerance, you should instead consider the network topology -- as in, which routes between honest nodes include corrupt nodes. This is also considered by the paper, since corrupt nodes can censor or rewrite messages, and thus influence how many corrupt nodes the system can truly tolerate, given a network topology. But in no case does message delay give a BFT system's node an excuse to make forward progress without first verifying that at least 2f+1 replicas agree with its decision. Even voting on a view change to remove a presumed dead node requires a 2f+1 vote.

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