Towards practical RAM based secure computation

Abstract

Secure multi-party computation (MPC) protocols are powerful privacy enhancing technologies. Yet, their scalability is limited for data intensive applications due to the circuit computation model. Therefore, RAM based secure computation (RAM-SC) has been proposed, which combines MPC with Oblivious RAM (ORAM). Unfortunately, realizing efficient RAM-SC applications by hand is a tedious and error-prone task, which requires expert knowledge in both cryptographic primitives and circuit design. To make things worse, a multitude of ORAMs with different trade-offs has been proposed. To overcome this entry barrier to RAM-SC, we present a two-fold approach. First, we explore all cost dimensions of relevant ORAMs in various deployment scenarios. Second, we present a fully automatized compilation approach from ANSI-C to RAM-SC. The presented compiler analyzes the input source code and extracts relevant information about the usage patterns of all arrays in the code. The results of the analysis are then used to predict the runtime of suitable ORAMs and to identify the ORAM that achieves minimal runtime. Thus, for the first time, RAM-SC also becomes accessible to non-domain experts.