SCORAM: Oblivious RAM for Secure Computation.
Xiao Shaun Wang, Yan Huang, T-H. Hubert Chan, Abhi A. Shelat, Elaine Shi · 2014
Oblivious RAMs (ORAMs) have traditionally been mea-sured by their bandwidth overhead and client storage. We observe that when using ORAMs to build secure computa-tion protocols for RAM programs, the size of the ORAM circuits is more relevant to the performance. We therefore embark on a study of the circuit-complexity of several recently proposed ORAM constructions. Our care-ful implementation and experiments show that asymptotic analysis is not indicative of the true performance of ORAM in secure computation protocols with practical data sizes. We then present scoram, a heuristic compact ORAM de-sign optimized for secure computation protocols. Our new design is almost 10x smaller in circuit size and also faster than all other designs we have tested for realistic settings (i.e., memory sizes between 4MB and 2GB, constrained by 2−80 failure probability). scoram makes it feasible to per-form secure computations on gigabyte-sized data sets.