1. 多媒體網路安全實驗室 A Security Framework of Group Location-Based Mobile Applications in Cloud Computing Date ： 2012.07.17 Reporter : Hong Ji Wei Authors : Yu-Jia Chen and Li-Chun Wang From:2011 International Conference on Parallel Processing Workshops

2. 多媒體網路安全實驗室 OUTLINE INTRODUCTION 1 SYSTEM MODEL AND PROBLEM 2 IMSI-BASE JOIN SECURE ALGORITHM 33 ANALYSIS AND DISCUSSION 44 SIMULATION RESULTS 35 CONCLUSIONS 46

3. 多媒體網路安全實驗室 INTRODUCTION  With rapid advances in mobile communications and location-aware mobile devices.  Location based services (LBS) are emerging as one of the killer applications for the next generation m- obile systems.  Traditional LBS of mobile applications focusing on emergency services.  The current LBS in mobile systems are much more versatile and consist of router planners.

4. 多媒體網路安全實驗室  The LBS can be categorized into two types: 1.Location-Tracking : Tracks users’ footprints by frequent updating users’ locations, such as GOOGLE LATITUTE. 2.Position-Aware : Relies on the nearby stores’ locations around the served user’s position, such as FOURSQURE.COM.  FACEBOOK announced a new service called PLACES, which provides LBS to users with both their friends’ and nearby stores’ locations. INTRODUCTION

5. 多媒體網路安全實驗室 INTRODUCTION  This paper focuses on the two security perspectives of LBS using Outsource Database: 1. Privacy Ensuring the security of location data of user and avoiding be stolen by hacker. 2. Authentication Ensuring only legal users can access and update location information.

6. 多媒體網路安全實驗室 SYSTEM MODEL AND PROBLEM  The ODB - the key element for database as a service (DaaS) in cloud computing.  The customers of DaaS can utilize huge storage cap- acity through the Internet.  The security of mobile users’ locations becomes an important issue when the ODB is adopted.  Trusted third party (TTP) was not considered in our model because JOIN.

7. 多媒體網路安全實驗室 SYSTEM MODEL AND PROBLEM 1 2 3 4 5 6 7 8 9 10

8. 多媒體網路安全實驗室 SYSTEM MODEL AND PROBLEM  Data security issues can be classified as 1.Security during data transmission It’s can be resolved by SSL 、 IPSec 2.Security in data storage It’s rarely studied by other researcher

9. 多媒體網路安全實驗室 SYSTEM MODEL AND PROBLEM  JOIN is a location-based group scheduling service with ODB model.

10. 多媒體網路安全實驗室 IMSI-BASE JOIN SECURE ALGORITHM  IMSI is a unique global number that stored in SIM card for identifying subscriber in each phone.  A mobile phone user rarely changes the IMSI.  This algorithm include two functions: 1.Key generation function 2.Encrytion function

11. 多媒體網路安全實驗室 IMSI-BASE JOIN SECURE ALGORITHM  This algorithm can be divided into four steps: 1. Register 2. Log in 3. Initiate 4. Store

12. 多媒體網路安全實驗室 IMSI-BASE JOIN SECURE ALGORITHM  Register ClientJOIN ServerCloud Database ID,PW,KeyA,Group {Alan,123,AA,Food} Compute KeyA from IMSI Compute KeyB from KeyA with ID Group,KeyB {Food,8w}

13. 多媒體網路安全實驗室 IMSI-BASE JOIN SECURE ALGORITHM  Login ClientJOIN ServerCloud Database ID,PW {Alan,123} After ID/PW passed Keep this thread

14. 多媒體網路安全實驗室 IMSI-BASE JOIN SECURE ALGORITHM  Initiate ClientJOIN ServerCloud Database KeyA,Location,Group {AA,{40.7,-74},Food } All other members in this group Request location KeyA,Location {XY,40.9,-73} {W7,42.3,-71.1}

15. 多媒體網路安全實驗室 IMSI-BASE JOIN SECURE ALGORITHM  Store ClientJOIN ServerCloud Database Save all {KeyA, Imprecise Location} to the cloud database.

16. 多媒體網路安全實驗室 ANALYSIS AND DISCUSSION  It is assumed that the adversary does not know users’ IMSI number.  There are no effective ways to get somebody’s IMSI except stealing their SIM cards or break into the dat- abase of their telecom operator.  Analysis can be divided to three parts 1. Privacy 2. Authentication 3. Continuity

17. 多媒體網路安全實驗室 ANALYSIS AND DISCUSSION  Privacy ClientJOIN ServerCloud Database KeyA,Location,Group {AA,{40.7,-74},Food } Save all {KeyA, Imprecise Location} to the cloud database. Initiate Store

18. 多媒體網路安全實驗室 ANALYSIS AND DISCUSSION  Authentication ClientJOIN ServerCloud Database {ID,PW} {Alan,123} Login Initiate KeyA,Location,Group {AA,{40.7,-74},Food } Authentication

19. 多媒體網路安全實驗室 ANALYSIS AND DISCUSSION  Continuity  We hope that user location records can still be pres- erved and continued.  The new location data can append to the same histo- ric records.  User identification in the location database does not need to change frequently.

20. 多媒體網路安全實驗室 SIMULATION RESULTS

21. 多媒體網路安全實驗室 CONCLUSIONS  The location-base service will become a popular service on the cell phone in the future.  The security of location data is an important issue.  The author proposed an IJS algorithm that can im- prove privacy, authentication and continuity.  In the future, author will propose more efficient m- echanisms and algorithms to mobile phone for loc- ation data security in cloud computing.

22. 多媒體網路安全實驗室