SURVEY ON PROTECTING PRIVACY AND SECURITY IN XML INFORMATION BROKERING?

In a federated information system with diverse participants (from different organizations) such as data producers, data consumers, or both, the need of cross-organizational information sharing naturally arises. However, different types of applications often need different forms of information sharing. In particular, while some applications (e.g., stock price updating) would need a publish-subscribe framework, the on-demand information access is more suitable for other applications. A number of information brokering systems have been developed to provide efficient and secure information sharing. Many existing information brokering systems adopt server side access control deployment and honest assumptions on brokers. However, little attention has been drawn on privacy of data and metadata stored and exchanged within Information Brokering System (IBS). We proposed an Information Brokering System (IBS) on the top of a peer-to-peer overlay to support information sharing among loosely federated data sources. It consists of diverse data servers and brokering components, which help client queries to locate the data servers. However, privacy of data location and data consumer can still be inferred from metadata (such as query and access control rules) exchanged within the IBS, but little attention has been put on its protection. We studied the problem of privacy protection in information brokering process. A formal presentation of the threat models with a focus on two attacks: attribute-correlation attack and inference attack is been performed. We propose a flexible and scalable system using a broker-coordinator overlay network. Through an innovative automaton segmentation scheme, distributed access control enforcement, and query segment encryption, proposed system integrates security enforcement and query forwarding while preserving system-wide privacy. We performed a comprehensive analysis on privacy, end-to-end performance, and scalability, the proposed system integrate security enforcement and query routing while preserving system-wide privacy with reasonable overhead.