Commutative encryption: an answer to privacy protected query processing of multi data sources

Abstract

This paper proposes a privacy-preserving collaborative query service by a service provider for customer's information on demand by secured processing of multi-source data. The customer and the data sources are unknown to each other. The service provider acts as a bridge between them for servicing the query while preserving privacy. The privacy of a query is determined by the constants associated with its predicates. Protecting the privacy of queries is an extremely important consideration for individuals/agencies that like to receive query results but do not want to reveal the query text. The data owners, on the other hand, are apprehensive about the privacy of their data and therefore hesitate to spare with their data. Moreover, the customer needs not to know who the contributors to the data are and the data owners should be anonymous to the customer as well. We have provided a solution to this problem. Secure data exchange by commutative encryption is the basic cryptographic approach considered in this work.