MPOPE: Multi-provider Order-Preserving Encryption for Cloud Data Privacy

Order-preserving encryption (OPE) has been proposed as a privacy-preserving query method for cloud computing. Existing researches of OPE diverge into two groups. One group focuses on single data provider scenarios and achieves strong security notion such as indistinguishability under ordered chosen plaintext attack (IND-OCPA). Another group of research designs multi-provider schemes and provides weaker security guarantees than those of single provider schemes. In this paper, we propose a novel security notion for multi-provider scenario, indistinguishability under multi-provider ordered chosen plaintext attack (IND-MPOPCA), which guarantees equivalent security level as IND-OCPA while hiding the frequency of plaintexts and enabling multi-provider data submissions and queries. We develop a multi-provider randomized order technique to construct our MPOPE scheme to achieve the IND-MPOPCA security notion. We also conduct extensive experiments to prove the practicality and efficiency of our proposed scheme.