In-broker access control: A new access control deployment strategy towards optimal end-to-end performance of information brokerage systems

An XML brokerage system is a distributed XML database system that comprises of data sources and brokers which, respectively, hold XML documents and document distribution information. Databases can be queried through brokers with no schema-relevant or geographical difference being noticed. However, all existing information brokerage systems view or handle query brokering and access control as two orthogonal issues: query brokering is a system issue that concerns costs and performance, while access control is a security issue that concerns information confidentiality. As a result, access control deployment strategies (in terms of where and when to do access control) and the impact of such strategies on end-to-end system performance are (in general) neglected by existing information brokerage systems; and data source side access control deployment is taken-for-granted as the “right” thing to do. In this paper, we challenge this traditional, taken-for-granted access control deployment methodology, and we show that query brokering and access control are not two orthogonal issues because access control deployment strategies can have significant impact on the “whole” system’s end-to-end performance. We propose the first in-broker access control deployment strategy where access control is “pushed” from the boundary of an information brokerage system into the “heart” of the system. We design and evaluate the fist in-broker access control scheme for information brokerage systems. Our experimental results indicate that information brokerage system builders should treat access control as a system issue as well.