RPM: Robust Anonymity at Scale

This work presents RPM, a scalable anonymous communication protocol suite using secure multiparty computation (MPC) with the offline-online model. We generate random, unknown permutation matrices in secret-shared fashion and achieve improved (online) performance lightest overhead for clients compared to state of art robust protocols. Using square-lattice shuffling, we make our scale well as number increases. provide three variants, each targeting different input volumes MPC frameworks/libraries. Besides, due modular design, protocols can be easily generalized support more functionalities security properties they get developed. also illustrate how generalize two-way sorting. have implemented MP-SPDZ library suit benchmark illustrates that unprecedented online phase practical offline phases.