The single distinction behind every MEV-protection product.
Public mempool: your transaction is broadcast to everyone and waits in the open, where bots can front-run or sandwich it — but it’s permissionless and maximally censorship-resistant. Private mempool: your transaction goes straight to builders, invisible to bots, usually with rebates — at the cost of a little centralization and inclusion delay.
Keeps the openness of a shared mempool but encrypts contents, aiming for protection without centralization.
Private mempools trade a little decentralization for strong protection and rebates; encrypted mempools (Shutter) try to give you both.