Encrypted mempools are one of the cleanest ideas in MEV mitigation: hide transaction details until it’s too late to front-run them. If validators (or a threshold committee) can’t see the payload, they can’t easily: - copy a trade, - sandwich it, - sell the order flow, - or pre-position around it. In this case you’re replacing “everyone sees everything instantly” with “reveal happens later and must be coordinated.” The main costs show up as: ➤ latency / delay where some designs require a reveal phase, a decryption window, or preconfirmations. That can add time before execution certainty. ➤ coordination risk where someone has to decrypt (a validator set, a committee, or a mechanism). If they fail, stall, or collude, user experience degrades. ➤ new failure modes where key management, liveness assumptions, and “who learns what when” become part of your protocol surface area. So encrypted mempools aren’t a free lunch, instead they’re a conscious decision to pay a coordination cost to reduce visibility.