BIP 54 mitigates the threat but does not provide sufficient protection.

It takes 1500s to verify a block down to 5s, which is still 500% worse than what most are used to in IBD so far.

We should be restricting scriptPubKey length. 520b was good, 34b is even better.

cryptoquick

I imagine the Great Consensus Cleanup (which also addresses many of these cases) could probably get more widespread support than BIP 110.

Given that BIP 110 has been mostly marketed as reducing arbitrary data, it feels like a strange way to go about dealing with quadratic hashing et al concerns.

Hunter Beast - Dev, Rust, Bitcoin

I imagine the Great Consensus Cleanup (which also addresses many of these cases) could probably get more widespread support than BIP 110. 

Given that BIP 110 has been mostly marketed as reducing arbitrary data, it feels like a strange way to go about dealing with quadratic hashing et al concerns.