Multi user searchable encryption schemes using Trusted Proxy for cloud based Relational Databases

Use of cloud Database-as-a-Service (DaaS) is gradually increasing in private and government organizations. Organizations are now considering outsourcing of their local databases to cloud database servers to minimize their operational and maintenance expenses. At the same time, users are apprehensive about the confidentiality breach of their vital data in cloud database. To achieve complete confidentiality of such data in outsourced databases, it is required to keep data in always-encrypted form in its entire life cycle i.e. at rest, in transition and while in operation in premises of cloud database services. Searchable encryption is a scheme, which allows users to perform an encrypted keyword search on encrypted data stored in database server directly without decrypting it. In many applications, it requires to access the database by multiple users where data is written by different users using different encryption keys. In this paper, we propose schemes for Multi user multi-key Encryption Search for cloud Relational Databases (MES-RD). It supports search operation on data encrypted under different keys by multiple users using a Trusted Proxy. These data may be stored in a shared table under one or other column of database server. To the best of our knowledge, the proposed schemes MES-RD are practical and first time proposed for databases.