Security of Applications Involving Multiple Organizations and Order Preserving Encryption in Hybrid Cloud Environments

Security of data stored and processed on the public cloud is a major concern. In this paper we argue that hybrid clouds provide an ideal environment for applications which require cooperation of multiple organizations, each organization has to coordinate some aspects of its activity and share some data with several other organizations, yet has strict security requirements for its own private data. Such applications could benefit from a hybrid cloud environment. Ideally, "big data" should be encrypted and stored on the public cloud. Private data should be migrated and processed on the private cloud while non-confidential data should be processed on the public cloud. We apply Order Preserving Encryption (OPE) for the sensitive fields of a data record and argue that this solution balances security concerns with efficiency for some applications. To illustrate our approach we discuss an implementation of the OPE and present a hybrid cloud solution for the control of a smart power grid.