Metadata management in encrypted outsourced databases

Database outsourcing is becoming increasingly popular introducinga new paradigm, called database-as-a-service, where a client’sdatabase is stored at an external service provider. Outsourcing databasesto external providers promises higher availability and more effective disasterprotection than in-house operations. This scenario presents newresearch challenges on which the usability of the system is based. In particular,one important aspect is the metadata that must be provided tosupport the proper working of the system.In this paper, we illustrate the metadata that are needed, at the clientand server, to store and retrieve mapping information for processing aquery issued by a client application to the server storing the outsourceddatabase. We also present an approach to develop an efficient accesscontrol technique and the corresponding metadata needed for its enforcement.