Presentation Outline Introduction Related Work System Architecture - PDF document

Privacy Protected Query Processing Privacy Protected Query Processing Privacy Protected Query Processing on Spatial Networks on Spatial Networks on Spatial Networks Wei-Shinn Ku Roger Zimmermann Wen-Chih Peng Sushama Shroff Third International Workshop on Privacy Data Management April 16, 2007 Presentation Outline � Introduction � Related Work � System Architecture � Privacy Protected Query Algorithms � Simulation Results � Future Research Directions 1

Introduction � Spatial Queries � Nearest neighbor queries � Window queries � Spatial join queries � Mobile Computing � PDAs � Cell and Smart phones � Laptops • The global sales volume of GPS devices, laptops, and PDAs were around 18 mil, 65 mil, and 7.5 mil respectively in 2006. IDC Research http://www.idc.com/home.jhtml Motivation � The proliferation of mobile devices � PDAs, cell phones, laptops, etc. � The popularity of positioning devices � GPS, GLONASS, GALILEO, etc. � Privacy threat from accessing Location-Based Services � e.g., “ Find my closest bank ” � How to protect mobile users’ identities? 2

Contributions � We propose a novel algorithm for solving privacy protected nearest neighbor queries on spatial networks. � We extend our nearest neighbor query solution to answer range queries with protection of privacy. � We demonstrate the feasibility and efficiency of our approach through extensive simulations. Presentation Outline � Introduction � Related Work � System Architecture � Privacy Protected Query Algorithms � Simulation Results � Future Research Directions 3

Spatial Queries - NN � Spatial network nearest neighbor algorithm – Incremental Network Expansion [Papadias et al. 2003] K -Anonymity � The mechanism to blur the identities of K users [Swe02]. � One trusted server (i.e., the location cloaker) is needed to cloak K users’ locations for protecting user privacy. 4

Presentation Outline � Introduction � Related Work � System Architecture � Privacy Protected Query Algorithms � Simulation Result � Future Research Directions System Architecture 5

System Architecture (Cont.) � Access Point � PDAs, cell phones, laptops, etc. � Location-based Service Providers � e.g., “ Find my nearest gas station ” - users have to reveal their identity. � Location Cloaker � A trusted server which implements K -Anonymity mechanisms and manages the location of users. � User privacy policies – K-anonymous and the minimum cloaked region size. � Need new query processing algorithms. Presentation Outline � Introduction � Related Work � System Architecture � Privacy Protected Query Algorithms � Simulation Results � Future Research Directions 6

Privacy Protected Nearest Neighbor Query - Preprocessing Privacy Protected Nearest Neighbor Query (k = 1) 7

Privacy Protected Range Query Presentation Outline � Introduction � Related Work � System Architecture � Privacy Protected Query Algorithms � Simulation Results � Future Research Directions 8

Simulation Parameter Sets Simulation - Cloaked Region Size 9

Simulation – Number of POI Simulation – Real World Parameters 10

Presentation Outline � Introduction � Related Work � System Architecture � Privacy Protected Query Algorithms � Simulation Results � Future Research Directions Future Research Directions � Cache management techniques for the location cloaker. � Cloaking by road segments. � Solution set size reduction. 11

Questions & suggestions 12