Securing of Clouds Based on Lightweight Secure Multi-party Computation

To prevent leakage and misuse of data stored in the cloud, a secure computation method that can calculate encrypted data has been studied. Though early secure computations were not practical due to large computation times, secure multiparty computations having smaller computation times have been proposed in recent years. However, in the basic secure multiparty computation in which addition and subtraction, or multiplication and division coexist, cloud servers must return the intermediate result to the client once. Therefore, clients’ communication and computation costs become large. Moreover, the application of relatively complex calculations had not been sufficiently examined. In this paper, we introduce a mechanism to exchange the intermediate result between servers securely and to return only the final result to the client. Also, we apply the lightweight secure multi-party computation to a Fourier transformation, a range search, and detection of data outliers.