Necessary Conditions in Multi-Server Differential Privacy. (arXiv:2208.08540v1 [cs.CR])

We consider protocols where users communicate with multiple servers to
perform a computation on the users' data. An adversary exerts semi-honest
control over many of the parties but its view is differentially private with
respect to honest users. Prior work described protocols that required multiple
rounds of interaction or offered privacy against a computationally bounded
adversary. Our work presents limitations of non-interactive protocols that
offer privacy against unbounded adversaries. We show these protocols demand
exponentially more samples for some learning …

conditions differential privacy privacy server