1. 1 Privacy Aware Incentive Mechanism to Collect Mobile Data While Preventing Duplication Junggab Son*, Donghyun Kim*, Rasheed Hussain**, Sung-Sik Kwon*, Alade O. Tokuta*, and Jungtaek Seo*** *Department of Mathematics and Physics, North Carolina Central University, Durham, NC, USA **Department of Computer Science, Innopolis University, Kazan, Russia ***Department of Computer Science and Engineering, Hanyang University, South Korea

2. 22 Agenda Introduction System Model Problem Definition Adversary Models and Assumption Preliminaries Proposed Scheme Analysis of security and privacy Conclusion

3. 33 Introduction Mobile sensing environment –A service provider can provide better service using sensing data from users –Interestingly enough, many of the existing researches treat a user as volunteer –This may not be true for many reasons Rare valuable sensing data, battery life, system performance, etc. Incentive scheme to collect high-quality sensing data from users –The service provider gives a (undeniable and unforgeable) credit to a user who has completed a given sensing task –Privacy must be considered

4. 44 Introduction – cont’ Using a pseudonym based privacy preserving scheme –Preserve privacy –On the other hand, sensing report duplication attack becomes possible due to anonymity Makes lots of noise, causes more cost to operate an application Propose a privacy preserving incentive scheme with effective checking –Functional pseudonym can reveal attacker’s private key in case of misbehavior

5. 55 System Model Credit Authority Service Provider … Participants Data Consumer Task / Report Payment / Registration & Credit Request / Result Pay credit

6. 66 Problem Definition Service Provider Sensing Data Duplication Incentive

7. 77 Adversary Models and Assumption Adversary models –Attacks on incentive A user may try to earn more credit than expected for sensing task A service provider may try to pay less or 0 credit than assigned on sensing task –Attacks on privacy User privacy can be invaded by the service provider or the other malicious parties Assumption –The communication between users and the service provider is anonymized IP and MAC address recycling techniques or Mix networks

8. 88 Preliminaries

9. 99 Preliminaries – cont’

10. 10 Preliminaries – cont’

11. 11 Preliminaries – cont’

12. 12 Proposed Scheme

13. 13 Proposed Scheme – cont’

14. 14 Proposed Scheme – cont’

15. 15 Proposed Scheme – cont’

16. 16 Proposed Scheme – cont’

17. 17 Proposed Scheme – cont’

18. 18 Privacy Analysis

19. 19 Security Analysis Security on Incentives –Dishonest user sends multiple sensing data to SP The private key of the user will be revealed by our scheme –Dishonest user eavesdrops other credit and sends it to CA It cannot pass the verification process of CA –Dishonest user sends same credit to the CA repeatedly It will be easily detected due to the task number and actual ID of the credit

20. 20 Conclusion Privacy-aware incentive scheme in mobile sensing –It is hard to detect duplicated sensing data from pseudonym communication Service Provider can revoke the private key of attacker –If an attacker performs sensing data duplication attack –Without help of a revocation authority or a trusted entity –It gives an attacker strong punishment

21. 21 Thank you. Questions? 21