QUERY OPTIMIZATION IN ENCRYPTED DATABASE SYSTEMS

A client-server relational database system includes a client computer connected to a server computer via a network. Data from the client computer is encrypted by the client computer and hosted by the server computer. The encrypted data is operated upon by the server computer to produce an intermediate results set. The intermediate results set is sent from the server computer to the client computer where it is operated upon by the client computer and then returned to the server computer where it is further operated upon by the server computer before being sent again from the server computer to the client computer in order to produce actual results.