A Geometric Stack for Location-Aware Networking. Marco Gruteser, Rich Martin WINLAB, Rutgers University

Transcription

1 A Geometric Stack for Location-Aware Networking Marco Gruteser, Rich Martin WINLAB, Rutgers University

2 Why Location-Aware Networking? The Revenge of Geography Low-cost localization Point-of-Interest Queries Finding nearby hotels, gas stations; travel guides, local entertainment Reverse 911 Emergency notifications to geographic area Navigation Navigation traffic-aware travel time optimization Improved information for traffic engineering Fleet management Tracking fleet of company vehicles Determining legal restrictions Automotive safety Extended electronic brake light Red-light warning Intersection collision avoidance Social Networking

3 Location Services Application Service Providers Location Service WLAN Positioning Subscribe to location updates Privacy Controls (Access Control) GPS coordinates Our Goals Location service to support network protocols location of infrastructure Components Location Service for applications using aggregate location data With privacy support through depersonalization

4 Novel use of location driven by new wireless technologies Example: Beamforming with Smart Array Antennas Internet

5 Directionality and Base station diversity Tradeoff Internet Internet? Base station diversity e.g. Soft Handoff [JSAC94], ViFi [SIGCOMM08] Directionality e.g. MobiSteer [MobiSys07] Challenge: Large search space (#[beam patterns] + #[rcvrs] + #[rates]) & high mobility

6 R2D2: Robust Rate with Directionality & Diversity Key Idea: Use location-based history for fast convergence pos -> ABSid, Angles, Erate P2 -> BS2, 90;135, 50.9 Location Registry Internet BS Backplane BS1 BS2 BS3 BS4 WWAN p0 p1 p2 p3 p4

7 Experimental Results

8 Other applications of Public AP Location Service Low-delay Vehicle-2- Infrastructure Communication Location-based Handoffs (Samir Das, Stony Brook) Localization (Placelab, Skyhook) Management? Location Service Signal Measurements Lat, Lon, APid, Bearing, SNR AP Locations Lat, Lon, APid

9 Geocoding can seed Location Registry Database can then be maintained through user contributed updates 6, Edith Place, Somerset NJ :02:23:34:23: Holland Drive, Princeton, NJ :AB:23:45:53:56 ISP Billing 00:02:23:34:23: :AB:23:45:53: BootStrapped Location Service Geocoding DB 6, Edith Place, Somerset NJ , Saw Mill Dr, Somerset, NJ Holland Drive, Princeton, NJ

10 Location Services Application Service Providers Location Service WLAN Positioning Subscribe to location updates Privacy Controls (Access Control) GPS coordinates Our Goals Location to support network protocols location of infrastructure Components) Location Service for applications using aggregate location data With privacy support through depersonalization

11 Applications using Aggregate Loation Data Anonymization GPS Satellite Cellular Service Provider Location Proxy Traffic Estimation Data mining and logging Access Control Probe Vehicles Vehicle ID timestamp Lon Lat Speed Heading ,18-oct :11:12, , ,42.18, ,18-oct :11:12, , ,63.72, ,18-oct :11:12, , ,50.15,75 254,18-oct :12:12, , ,45.18, ,18-oct :12:12, , ,60.01, ,18-oct :12:12, , ,45.88, ,18-oct :21:12, , ,45.67,135 Anonymous Trace log files

12 Inference/Insider Attacks Compromise Location Privacy Still insider breaches and remote break-ins possible..... Re-identification of traces through data analysis Tracking algorithms recover individual trace [Hoh05] (Median trip time only 15min) Anonymous Trace log files Home Identification [Hoh06] GPS often precise enough to identify home

13 Stronger De-identification for Location Traces: Filtering based on Tracking Model t=t 1 d 2 d 3 d 1 t=t 2 d 1 d 2 d 3 t=t 2 t=t 1 t=t 2 t=t 2 t=t 2 t=t 2 Low Entropy Low Uncertainty High Entropy High Uncertainty Uncertainty Normalization

14 Virtual Trip Lines (VTLs) - Sampling in Space Crossing Virtual Trip Lines trigger Location Updates, rather than periodic update Local VTLs stored in phone Allows generating (anonymous) updates only from key roads, presumably less sensitive areas!

15 Split-Secret VTL Architecture Ensure PRIVACY VTL Placement Restrictions VTL Generator VTL DataBase Satellite Sensing measurement Endto-end encryption VTL download ID Proxy VTL Caching VTL updates VTL Server VTL Update Log VTL Crossing Detection Secure HTTP Encrypted RPC Traffic monitoring service provider Cellular Networks Make Updates ANONYMOUS Strip IP/Phone ESN address Check right to use system Filter suspicious updates Ensure PRIVACY Aggregation Query Restrictions Traffic Estimation Data mining and logging Traffic estimation feedback through TMC

16 Cloaking Extensions and Secret Splitting Distributed VTL-Based Temporal Cloaking Traffic estimation is relatively immune to temporal error No single entity (except handset) has access to both location and time Entity Role Identity Location Time Handset Sensing Yes Accurate Accurate Location Verifier Distributing VTL ID updates Yes Coarse Accurate ID proxy Anonymizing and Cloaking Yes Not available Accurate Traffic Server Computing Traffic Congestion No Accurate Cloaked Virtual Trip Lines Temporal Cloaking

17 Experiment (20-cars, 1~2% penetration rate) Longer route Shorter route

18 Summary Location Service Signal Measurements Lat, Lon, APid, Bearing, SNR AP Locations Lat, Lon, APid

19 Thank you