FutORAMa: A Concretely Efficient Hierarchical Oblivious RAM

Oblivious RAM (ORAM) is a general-purpose technique for hiding memory access patterns. This is a fundamental task underlying many secure computation applications. While known ORAM schemes provide optimal asymptotic complexity, despite extensive efforts, their concrete costs remain prohibitively expensive for many interesting applications. The current state-of-the-art practical ORAM schemes are suitable only for somewhat small memories (Square-Root ORAM or Path ORAM).