Presentation Outline Introduction Related Work System Architecture - - PDF document

1

Privacy Protected Query Processing Privacy Protected Query Processing Privacy Protected Query Processing

• n Spatial Networks
• n Spatial Networks
• n 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

2

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?

3

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

• ur approach through extensive simulations.

Presentation Outline

Introduction Related Work System Architecture Privacy Protected Query Algorithms Simulation Results Future Research Directions

4

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.

5

Presentation Outline

Introduction Related Work System Architecture Privacy Protected Query Algorithms Simulation Result Future Research Directions

System Architecture

6

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

7

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

8

Privacy Protected Range Query

Presentation Outline

Introduction Related Work System Architecture Privacy Protected Query Algorithms Simulation Results Future Research Directions

9

Simulation Parameter Sets

Simulation - Cloaked Region Size

10

Simulation – Number of POI

Simulation – Real World Parameters

11

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.

12

Questions & suggestions