International Journal of Computer Science and Mobile Computing (IJCSMC)
Information sharing among organizations has been increased these days. To connect large scale loosely-federated data sources, Information Brokering System (IBSs) have been introduced. In this paper, the brokers make routing decisions to direct the client queries to the requested data servers. Many existing IBSs assume that brokers are trusted and thus only adopt server-side access control for data confidentiality. Yet, 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 concentration has been set on its protection.