Participatory Sensing through Social Networks: The Tension between Participation and Privacy


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This paper corresponds to publication:
I. Krontiris, F.C. Freiling, "Urban Sensing through Social Networks: The Tension between Participation and Privacy", International Tyrrhenian Workshop on Digital Communications (ITWDC), Island of Ponza, Italy, September 2010.

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Participatory Sensing through Social Networks: The Tension between Participation and Privacy

  1. 1. Participatory Sensing through Social NetworksThe tension between Participation and Privacy<br />ITWDC6-8 September, 2010<br />I. Krontiris, <br />Chair of Mobile Business<br />Goethe University Frankfurt<br /><br />F.C. Freiling, <br />LehrstuhlPraktischeInformatik I<br />University of Mannheim<br />
  2. 2. Paper outline<br />What are the benefits and drawbacks of connecting social network with participatory sensing? <br />We study this relation in 2 dimensions that conflict with each other:  Social translucence (visibility) and Privacy<br />Goal: Identify and discuss research challenges that arise in this new setting.<br />
  3. 3. Available Sensors Today<br />
  4. 4. Available Sensors Tomorrow<br />
  5. 5. External Sensors<br />
  6. 6. NoiseTube<br />
  7. 7. Architecture Overview<br />
  8. 8. Research Questions<br />Share – How will collected data be shared? What practices of individual ownership will be appropriate and how will privacy be addressed? How can data best be shared with non-experts, urban planers, decision and policy makers, etc.?<br />Change – What tools or frameworks best invite and encourage active participation? What tools and techniques will facilitate the most productive debate and ultimate positive social benefit?<br />
  9. 9. Utilizing Social Networks<br />Benefit 1: Recruitment (getting people to join)<br />identify and reach well-suited participants for data collections based on their geographic availability as well as their interests and habits.<br />allow existing participants to invite their friends to join a group, or see what their friends are doing (which group they joined, in which groups they are most active), etc.<br />
  10. 10. Utilizing Social Networks<br />Benefit 2: Participation (getting people to participate)<br />No direct benefits for participants. Why should those who can produce the sensing data take the time to engage in such interactions? Why should they wish to?<br />Sense of Community<br />Sense of efficacy: a sense that they have had some effect on the group.<br />
  11. 11. Utilizing Social Networks<br />RecognitionReputation Points<br />a user, after submitting a report from his mobile phone, is given a reputation point. <br />reputation points are public and appear on the public profile of that user.<br />
  12. 12. Utilizing Social Networks<br />Benefit 3: Acting on the data<br />Not all data are equally useful / important<br />People could also intentionally submit fault data<br /> Pre-evaluation by the users<br />Example: A system that allows users to submit images of potholes on the street<br />
  13. 13. location privacy<br />
  14. 14. Privacy vs. Visibility<br />Knowing when a particular person was at a particular point in time can be used to infer a lot of personal information<br />Allow users to make their contributions visible to the online community<br />Anonymity<br />Social Translucence<br />
  15. 15. Research question<br />System model: Users submitting data are anonymous, but at the same time they maintain a public profile in the social network, where they provide details about themselves (e.g. reputation, etc.)<br />Is it possible to offer anonymity to the user, who submits sensing data from the physical environment, while at the same time we maintain properties connected with his public profile, like <br />Reputation and<br />User revocation?<br />
  16. 16. <br /> Anonymity<br />Let’s assume we provide anonymity to protect user’s privacy<br />Data are anonymized<br />Hide network identifiers<br />
  17. 17. Reputation<br />Giving reputation points to an anonymous user is not possible<br />Need two independent processes:<br />A pseudonymous user acquires reputation points (one-time pseudonym)<br />A known user updates its reputation in his public profile<br />Solution direction: Use e-cash systems<br />A pseudonymous user obtains e-coins from the bank for a report submission, which corresponds to a reputation point<br />At a later point in time, the user logs-in using his public profile and redeems the e-coin to increase his reputation.<br />Hard: Repetitions of this process should not be linkable!<br />
  18. 18. User revocation<br />Before submit, user authenticates anonymously to the service provider <br />This encourages user misbehavior need for user revocation<br />Revocation depends on anonymous authentication mechanism:<br />If use group signatures: A Trusted-Third-Party manages user accounts and has the ability to revoke user’s anonymity at any time. No assurances that TTP is reliable!<br />If use e-cash: Anonymity is revoked if spent an e-coin twice<br />If use k-Times Anonymous Authentication: Anonymity is revoked if user authenticates more than k times. <br />None of this appropriate. Need a d-strikes-out revocation system<br />When users are judged to have misbehaved d times, they are revoked by the system<br />Some protocols exist, but very expensive for power-limited mobile phones<br />
  19. 19. Conclusions<br />Utilization of social networks could provide many benefits in urban sensing<br />recruit more citizens in campaigns and boost their active participation. Example: use of reputation systems<br />It is also important to preserve the anonymity of the users submitting data<br />Anonymity makes it hard to revoke misbehaving users or compute their accumulated reputation points<br />Acknowledgment: Thanks to Nicolas Maisonneuve for the inspiring conversations<br />