F. Li 05/15/06 Security & Privacy Preserved Information Brokerage System Fengjun Li College of IST, Penn State University

F. Li 05/15/ Introduction Information Brokerage Systems Security- preserved mechanism Privacy- preserved mechanism Conclusion and Q&A

F. Li 05/15/06 content/location discovery Universal Connectivity security & privacy risks poor usability …

F. Li 05/15/06 Data sources connected with the help of brokers User send query to local broker that help route it to targeted data sources Information Brokerage System Security & privacy?

F. Li 05/15/06 Security Enforcement – from the perspective of performance –Access Control –Traditional AC enforcement and IBS architecture –Any other choice

F. Li 05/15/06 If we could drag the AC out of DBMS … Or further

F. Li 05/15/06 Why dragging security check out of DBMS and pushing it to the brokers? – A performance based reason

F. Li 05/15/06 Preliminary –XML Access Control Model Role-based Access Control 5-tuple access control rules (ACR) –QFilter: enforcing AC via query written Using Non-deterministic Finite Automata (NFA) to hold ACR Query either rejected or accepted (w/o rewritten)

F. Li 05/15/06 QFilter Example

F. Li 05/15/06 Our Approach –Merge the QFilters of several roles to an integrated Multi-Role QFilter A naïve approach – QFilter Array –Use the similar NFA-based mechanism to represent the routing information (called index rules) –Merge index rules into Multi-Role QFilter for further performance improvement

F. Li 05/15/06 An Example of Multi-Role QFilterAn Example of Index Rules

F. Li 05/15/06 An Example of Indexed Multi-Role QFilter - Merging index rules into Multi-Role QFilter

F. Li 05/15/06 Why dragging security check out of DBMS and pushing it to the brokers? – Previous example re-visit

F. Li 05/15/06 Performance Metrics 1 - Memory Consumption Performance Metrics 2 – In-broker Query Response Time & Overall Query Response Time Performance Metrics 3 –Network Traffic - Save 87.5% (by analyzing)

F. Li 05/15/06 Privacy Preserving Mechanism –Possible privacy breaches: Privacy of the query location Privacy of the query content Privacy of the access control rule Privacy of the data location Privacy of the data content

F. Li 05/15/06 Information Brokerage System –New architecture

F. Li 05/15/06 Trust Relationship PrivacyUserBrokerCoordinatorData Server Query Location -Trust Hide Query Content -Hide Trust (Partially) Trust ACR Hide Trust (Partially) Trust (for double-checking) Data Location Hide (Partially) - Data Content With authorizationHide -

F. Li 05/15/06