1. Enhancing Security and Privacy in Online Social Networks Sonia Jahid sjahid2@illinois.edu University of Illinois at Urbana-Champaign PhD Forum

2. Online Social Network (OSN)

3. Motivating Examples

4. Our Goal … A Private and Secure Online Social Network Shift the access enforcement point from the provider to the users 4

5. Decentralization Provider Trusted Party Myself Hybrid Untrusted Party Availability Access control by others Confidentiality/Integrity Malicious activities

6. Wall Status Comment Video Link Complicated OSN Data and Access Control

7. Access Control – Attribute-based encryption with efficient revocation Architecture Design – Distributed hash table – Object oriented data – Efficient algorithm for newsfeed Our Contribution 7 EASiER – ASIACCS 2011, DECENT – SESOC 2012, CACHET – CoNEXT 2012

8. Example ObjectDataPolicyAnnotation GHC Rocks! Friend|Alice|F riend ObjectLike! Friend or Colleague|Bob|Frien d Reference Alice’s Status Bob’s Comment Read Write/Delete Append

9. Application?

10. Our Goal Health Information Exchange – Patient-centric health data through a secure distributed storage service 10

11. Challenges Confidentiality, Integrity, Availability Private Audit Anonymous search Break the glass policy 11

12. Private Audit Properties – Authentication – Access Control – Auditing – Anonymity Concept – Revocable Anonymity Storage Data Access A0dan c*#- 3948s k3m4l ksfm p Logging Information 12 Doctor Nurse

13. Anonymous Search Properties – Anonymity – Efficiency – Correctness Concept – Public Key Encryption Keyword-based search – Private Information Retrieval Storage Alice, Lab 13

14. Break the Glass Policy Properties – Emergency access on data – Auditing Alice’s Data 14

15. Research Summary Techniques to enhance security and privacy of a social network Challenges and application of such techniques in healthcare domain Sonia Jahid http://www.soniajahid.com sjahid2@illinois.edu 15