Published: Dec 2011

Presented byIrfan Ullah

Department of Information and Communication Engineering Myongji university, Yongin, South Korea

uSafe: A Privacy-aware and Participative Mobile Application for

Citizen Safety in Urban Environments

Copyright © solarlits.com

• Objective• Introduction• Features• uSafe Architecture• Evaluation• Issues• Conclusions

Content

• Citizen’s safety• Privacy-aware application• Safety map• Involving 183 users

Objective

• Urban sensing• Collect and share sensed data• Applications• Personal environmental impact

report• Ear-phone• Traffic and road conditions

• Citizen’s safety?• 6 million crimes, Germany (2009)

• 92,500 pickpocketing• 370,000 bodily injuries• 48,000 robberies

Introduction

PEIR, lookup weather and traffic.

Signal processing to detect noise pollution

Traffic and road conditions through accelerometer, GPS, and microphone.

Introduction cont’d..

GarbageWatch project

1.9 million reviews in QypeRestaurants, doctors, or other available services.

Share experiences using foursquare

Qulaity of surroundings RateMyArea.com

Similar with uSafe Ushahidi.com

• uSafe• Participation

• Measuring safety level• Building maps by the server• For public to view safety area

• Privacy awareness• Protecting user’s privacy• Participate or refuse• Pseudonyms with blind

signatures

Introduction cont’d..

uSafe map

• Participative application• Maps to all users• Safe area rating with reason

• Location privacy of users• Periodic pseudonyms or

privacy zones• Identification of users• Delay reporting process

• Rewards for contribution

Features

uSafe map

• Alice moved to a new city• Registered uSafe• Phone vibrates in danger zone

• Invited by Bob for dinner• uSafe: Time, distance, and safety• Suddenly, phone vibrates• Then ?

Example

Path statistics Privacy settingsMap of safety ratingReached safely at home

• After few weeks• Alice decide to contribute to

the uSafe with privacy• Periodic pseudonyms instead of

unique ID• Clocked position instead of exact

• Reward• Discount for public swimming

pool

Example cont’d..

Path statistics Privacy settingsMap of safety rating

“Periodic pseudonyms breaks the link with successive contributions”

“Clocked position: 100 meters as clocking parameter”

• Overview• Client

• Report (real time or past)• Real identity or pseudonym

• Application server• Report processing

• Reward and pseudonym manager (RPM)

Architecture

Architecture of the uSaif

1) Report creation2) Report transmission3) Report processing4) Report visualization and

utilization

Reporting Mechanism

1) Report creation• Real time or retrospective• Continuous or discrete• Continuous: automatically

updating location and reason unless you change

Reporting Mechanism cont’d..

Selection of perceived safety level

Selection of reason for safety report

Example of privacy zones

2) Report Transmission• Wi-Fi/3G using HTTPS• Each user has

• Permanent identifier ID• Private key (cclient,nclient)• Public key (eclient,nclient)

• RPM produces keys for each period of time (T)• Private key (dsign,nsign)• Public key (esign,nsign)

Reporting Mechanism cont’d..

Generation process of both pseudonyms and RTs

• Each client has• Private key (dp,np)• Public key (ep,np)

• Client generates sp• Prepare message mp using np

• Public key (esign,nsign) valid for T• Blinding factor r modulo np

• Signature with permanent private key

• To get P (pseudonym)• Client transmits (mp, Smp, ID, and T) to RPM

Reporting Mechanism cont’d..

IncogniSense frameworkAfter verification, blind signature

Pseudonym signature for blind signature

3) Report Processing• Construct map• Attribute reward scores• Feelings into numeric values• Cloaks: to find sector• Average value for sector to define

colors• Rewards by identifying

pseudonyms• Live report: 20• Past report: 10

Reporting Mechanism cont’d..

Sector size of 100 m Sector size of 500 m Sector size of 5 km

Rewards15 10 5100 m 500 m 2,000 m

Numeric valuesI am feeling safe: 1I am worried: -50I am feeling unsafe: -100

3) Report Processing• Reward from previous pseudonym

• Reward token (RT)• Random bit stream IDRT

• Message for blind signature from public transfer key

• Signature using private key (dpcurrent, npcurrent) with current pseudonym (Pcurrent)

• Client transmits (mRT, SmRT, Pcurrent, and Rscore) to RPM• After verification, blind signature• Blind signature to generate final signature for RT

Reporting Mechanism cont’d..

4) Report visualization and utilization• For safety aware navigation

• Google Map API

• Safety hint• Average degree of safety

Reporting Mechanism cont’d..

Google Map API

1) Demographics• Male = 122• Age = 18-50• Total = 183

2) Personal experience• Irregular basis : 68%• Once: 9%• Daily: 3%• Monthly: 12%• Yearly: 8%

Evaluation

Demographics of the participants

Periods of the day at which the participants felt unsafe

Reasons given by the participants to explain their feeling of unsafeness

3) Interest in using uSafe• I would appriatiate using uSafe

application• 48 participants agreed to give

score

Evaluation cont’d..

Distribution of the answers by genderSituations in which the participants would like to use the uSafe

Distribution of the answers by safety experience

4) Safety hints• Would like being alerted by

mobile when about to enter in unsafe

• Dislike: 45%• Would like: 46%• 56% like to alert by phone

vibration

Evaluation cont’d..

Distribution of the answers by safety experience

Distribution of the answers by gender

5) Contributor’s propective• I would be ready to contribute to

the uSafe application (by reporting my safety feelings and giving the reasons of such feelings).

• Agreed: 44%• Disagreed: 36%• Realtime reporting: 34%• With delay: 24%• Neutral: 24%• Report about

• dark streets (21), drinking/drunken people (11), aggressive people (9), areas where drugs are usually sold/consumed (8), deserted places (3).

• Personal information: 20%• Would not give: 63%

Evaluation cont’d..

Distribution of the answers by safety experience

Distribution of the answers by gender

6) Privacy Concerns• By the participants

• I like your idea!• It can be a pretty handy application• This whole uSafe thing seems really

interesting to me• Great approach!• I strongly recommend you to carry on

this project

Evaluation cont’d..

On the importance of privacy for the participants and their preferences in term of anonymity and location cloaking

• Trustworthiness and Reliability• Issue: Difficult to distinguish honest from

falsified reports• Solution: From police databases or local

newspapers to improve the reliability

• Impacts of the Rating• Real discrimination between areas

• Issue: But, naturally avoid it afterwards• Solution: provide a wealth of

information to social workers, urban conflict managers, police, etc.

• Issue: people can become more afraid• Solution: using uSafe more

Discussion

• For citizen safety in urban environments• Participative application

• User gathered reports

• Privacy-aware• Unique identity or multiple pseudonyms• Cloak their location• Not real-time information• Delaying to transmit

• Future work• Integrate with other application

Conclusions

Thanks ?