86 ◾ Secure Data Provenance and Inference Control
7.4 Secure Query Processing in a Cloud Environment
To illustrate how the various cloud computing tools can be utilized, we describe
a prototype system that we have developed. Our prototype is a Web-based secure
cloud query processing system. It enforces XACML-based policies for access control
during query processing. We have combined HDFS with Hive to provide a com-
mon storage area for participating organizations. Users of our system are divided
into groups based on the kinds of queries that they can run, such as SELECT and
INSERT. Our system provides a secure login feature to users based on a salted hash
technique. When a user logs into our system, he or she is provided with different
options ...