Secure Graph Database Search with Oblivious Filter

With the emerging popularity of cloud computing, the problem of how to query over cryptographically-protected data has been widely studied. However, most existing works focus on querying protected relational databases, few work has shown interests in graph databases. In this paper, we first investigate and summarize two single-instruction queries, namely Graph Pattern Matching (GPM) and Graph Navigation (GN). Then we follow their design intuitions and leverage secure Multi-Party Computation (MPC) to implement their functionalities in a privacy-preserving manner. Moreover, we propose a general framework for processing multi-instruction query on secret-shared graph databases and present a novel cryptographic primitive Oblivious Filter (OF) as a core building block. Nevertheless, we formalize the problem of OF and present its constructions using homomorphic encryption. Finally, we conduct an empirical study to evaluate the efficiency of our proposed OF protocol.