1. Privacy for Location Based Community Services (LBCS)
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Georg Groh: Privacy for Location Based Community Services (LBCS)
Privacy for Location Based Community Services (LBCS)
(Georg Groh, Informatik, TUM)
LBCS vs. LBS
Consequences for Location Privacy
Original Rule-Based Concept
Original Concept Simplified
Still too complicated? (Latest Approach)
Prof. Dr. Dr. h.c. R. Reichwald
Prof. Dr. H. Krcmar
Prof. Dr. J. Schlichter
Prof. Dr. U. Baumgarten

2. LBCS vs. LBS LBCS LBS Examples Main Interaction Paradigm
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Georg Groh: Privacy for Location Based Community Services (LBCS)
LBCS vs. LBS
LBCS
LBS
Examples
Location based communication (Virtual Post It etc.), social navigation (FriendFinder, Ad-Hoc-Group Information Filtering etc.)
Location based Information Retrieval (Guides, Navigation, YellowPages etc.)
Main Interaction Paradigm
Push
Pull
Information Space
CIKS (Collaborative Information- and Knowledge Space)
determined by Provider
Location Update Paradigm
proactive, location up-to-date for all users at all times
on demand

3. Consequences for Location Privacy (I)
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Georg Groh: Privacy for Location Based Community Services (LBCS)
Consequences for Location Privacy (I)
General Paradim: Full Control about Location at all times
In LBS Location is usually revealed to provider only once. Information is not stored ->
Pro: Individual misuse potential is small.
Con: Trust in provider may be small if provider is unknown. LBCS: trust in community -> user may reveal more!
In LBCS Location is revealed to other community members (directly or indirectly via services) and kept up-to-date at all times -> User must
specify location privacy on a per-user-basis (Buddylists etc.)
have reasonably chosen granularity options.
User interface must be adapted to mobile use (ease of use)
Privacy configuration must be easily accesible and transparent
Prof. Dr. Dr. h.c. R. Reichwald
Prof. Dr. H. Krcmar
Prof. Dr. J. Schlichter
Prof. Dr. U. Baumgarten

4. Consequences for Location Privacy (II)
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Georg Groh: Privacy for Location Based Community Services (LBCS)
Consequences for Location Privacy (II)
General Paradim: Full Control about Location at all times
Proactiveness and Push paradigm -> User must
be able to control service context-sensitively (Reachability Management etc.) if desired.
be able to selectively block unwanted disturbances on a per-user-basis (Blacklists etc.)
Services must be designed to automatically respect privacy. Example: FriendAlert:
Original Design: „Inform me when a user on MY buddylist is near“
New Design: „Inform me, when a user is near who has ME on HIS buddylist“
Prof. Dr. Dr. h.c. R. Reichwald
Prof. Dr. H. Krcmar
Prof. Dr. J. Schlichter
Prof. Dr. U. Baumgarten

5. Consequences for Location Privacy (III)
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Georg Groh: Privacy for Location Based Community Services (LBCS)
Consequences for Location Privacy (III)
General Paradim: Full Control about Location at all times
LBCS: Location privacy is at least one order of magnitude more complicated than in case of LBS
Prof. Dr. Dr. h.c. R. Reichwald
Prof. Dr. H. Krcmar
Prof. Dr. J. Schlichter
Prof. Dr. U. Baumgarten

6. Original Rule-Based Concept (I)
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Georg Groh: Privacy for Location Based Community Services (LBCS)
Original Rule-Based Concept (I)
For every profile element (Location, Interests, Name etc.) configure a stack of rules
Rule: Condition (Profile A, Profile B) -> Result (Profile A, Profile B)
user A: asked user; user B: asking user (also via service).
Condition: Procedurally defined predicates over profile elements, AND, OR, NOT
Result: Procedurally defined functions oder profile elements
Example Rule Stack for Location Attribute:
isInBuddylist(B.name) > returnFull(A.location)
isNear(B.location, 100) > returnFull(A.location)
NOT equals(B.name, „BillGates“) > returnPartOfCity(A.location)
isSimilarVector(B.interests, A.interests) -> returnPartOfCity(A.location)
-> returnNothing
Prof. Dr. Dr. h.c. R. Reichwald
Prof. Dr. H. Krcmar
Prof. Dr. J. Schlichter
Prof. Dr. U. Baumgarten

7. Original Rule-Based Concept (II)
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Georg Groh: Privacy for Location Based Community Services (LBCS)
Original Rule-Based Concept (II)
Users choose for every Profile Element
A predefined standard Privacy Rule Stack (by name) OR
from a set of more special Privacy Rule Stacks (by name) OR
edit their own rules
Rule engine‘s condition processing unit was used to implement LBCS:
Virtual Post-It: <-> send Message to all users B that match
isNear(A.location, B.location) AND TimeFrame(begin, end)
Portable Message: <-> send Message to all users A that match
isNear(A.location, B.location)
etc.
Prof. Dr. Dr. h.c. R. Reichwald
Prof. Dr. H. Krcmar
Prof. Dr. J. Schlichter
Prof. Dr. U. Baumgarten

8. Original Concept Simplified (I)
8 / 10
Georg Groh: Privacy for Location Based Community Services (LBCS)
Original Concept Simplified (I)
Prof. Dr. Dr. h.c. R. Reichwald
Prof. Dr. H. Krcmar
Prof. Dr. J. Schlichter
Prof. Dr. U. Baumgarten

9. Original Concept Simplified (II)
9 / 10
Georg Groh: Privacy for Location Based Community Services (LBCS)
Original Concept Simplified (II)
Prof. Dr. Dr. h.c. R. Reichwald
Prof. Dr. H. Krcmar
Prof. Dr. J. Schlichter
Prof. Dr. U. Baumgarten

10. -> New Simplistic Prototype
10 / 10
Georg Groh: Privacy for Location Based Community Services (LBCS)
Still too complicated?!
Database analysis shows: only 43 of 72 participants made privacy settings. Most settings were „show all“
Online Survey shows: 40 of 57 participants claim to have made privacy settings. (consistent)
-> New Simplistic Prototype
...
exakte Position erlauben
Stadtteil Position erlauben
keine Position erlauben
Prof. Dr. Dr. h.c. R. Reichwald
Prof. Dr. H. Krcmar
Prof. Dr. J. Schlichter
Prof. Dr. U. Baumgarten