Vitalik: Client-side proof speed limits ZK-VM privacy applications

Ethereum co-founder Vitalik Buterin explains the limitations of ZK-VM (zero-knowledge virtual machine) for privacy use cases. One user pointed out that ZK-VM is better in almost every way, but ironically, the only use case they fail to cover is privacy. In response, Vitalik said: "The explanation is simple: privacy use cases require client-side proofs, and currently client-side provers are not fast enough to handle anything beyond Merkle branches." "To make matters worse, client use cases require each user to provide proofs, which means the proofs are small, and elliptic curve-based proof systems have slow proof times. You can solve this problem by having the client make a (ZK) STARK and send it to an intermediary. The intermediary will wrap it in an elliptic curve-based SNARK, but this is an additional base dependency, which brings other problems."