International Association for Cryptologic Research (IACR)
Abstract
Distributed Oblivious RAM (DORAM) protocols allow a group of participants to obliviously access a secret-shared array at a secret-shared index, and DORAM is the key tool for secure multiparty
computation (MPC) in the RAM model.
In this work, we present a novel 3-party semi-honest DORAM protocol with O((κ + D) log N) communication per access, where N is the size of the memory, κ is a security parameter and D is the block size. Our protocol performs polylogarithmic computation and does not require homomorphic encryption. Under natural parameter choices, this is the most communication-efficient DORAM with these properties.
To build this DORAM protocol, we first present an extremely efficient oblivious data structure for answering set membership queries. From this we build an oblivious hash table with asymptotically optimal memory usage and access cost and with negligible failure probability. We believe these are of independent interest
