This document proposes a two-stage solution for secure location-based queries that improves performance. The first stage uses oblivious transfer to privately determine the user's location within a public grid. The second stage uses private information retrieval for the user to efficiently retrieve an appropriate data block from the private grid. The solution introduces a formal security model and analyzes the security of the novel protocol. It aims to achieve privacy protection for both the user and server in location-based services.

1. ANALYSIS THE SECURE CONTENT
PROTECTING LOCATION BASED ON
QUERIES
Guided by
Ms v.Anusuya M.E
AP/IT
Presented by
PR.Kavidha(912411205006)
C.Vasanthi(912411205010)

2. ABSTRACT
• A solution to one of the location-based query problems. user wants
to query a database of location data, known as Points Of Interest.
• The first step is based on Oblivious Transfer. The second step is
based on Private Information Retrieval, to achieve a secure solution
for both parties.
• The solution we present is efficiency of our protocol. We also
introduce a security model and analyse the security in the context of
novel protocol.

3. EXISTING SYSTEM
• The location server (LS),which offers somes LBS spends its
resources to compile information about various interestingPOI.
• LS’sdata is not accessed by any unauthorized user.
Disadvantage:
• Not protected for the user and server.
• privacy assurance is the major issue

4. MODEL OF EXISTING SYSTEM

5. PROPOSED SYSTEM
• Location based queries that as major performance improvement two
stages.
• First stage the user privately determines his/her location within a
public grid,using oblivioues transfer.
• Second stage ,the user execute a communicational efficient PIR,to
retrieve the appropriate block in the private grid.

6. ADVANTAGES
• Redesigned the key structure
• Added a formal security model
• Implemented the solution of mobile device and desktop machine

7. ARCHITECTURE DESIGN

8. OBLIVIOUS TRANSFER PHASE
• QueryGeneration1 (Client) (QG1): QueryGeneration1 (Client) takes
as input indices i, j, and the dimensions of the key matrix m, n, and
outputs a query Q1 and secret s1, denoted as (Q1, s1) = QG1 (i, j, m,
n).
• ResponseGeneration1 (Server) (RG1): ResponseGeneration1
(Server) takes as input the key matrix Km×n, and the query Q1, and
outputs a response R1, denoted as (R1) = RG1(Km×n,Q1).
• ResponseRetrieval1 (Client) (RR1): ResponseRetrieval1 (Client)
takes as input indices i, j, denoted as (ki,j, IDi,j) = RR1 (i, j, m, n,
(Q1, s1),R1).

9. PRIVATE INFORMATION
RETRIEVAL PHASE
• QueryGeneration2 (Client) (QG2): QueryGeneration2 (Server) takes
as input the cell-id IDi,j , and the set of prime powers S, and outputs
a query Q2 and secret s2, denoted as (Q2, s2) = QG2(IDi,j , S).
• ResponseGeneration2 (Server) (RG2): ResponseGeneration2
(Server) takes as input the database D.
• ResponseRetrieval2 (Client) (RR2): ResponseRetrieval2(Client)
takes as input the cell-key ki,j and cell-id IDi,j , the query Q2 and
secret s2, the response R2, and outputs the data d, denoted as (d)
=RR2(ki,j, IDi,j , (Q2, s2),R2).

10. MODULES
1. Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure
2. Expedite Message Authentication Protocol
3. Security Analysis
a) Hash Chain Values
b) Resistance of forging attacks
c) Forward secrecy
d) Resistance to replay attacks
e) Resistance to colluding attacks

11. MODULES DESCRIPTION
1. Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure
• In this Module, the two basic communication modes, which
respectively allow OBUs to communicate with each other and with
the infrastructure RSUs.
• Since vehicles communicate through wireless channels, a variety of
attacks such as injecting false information, modifying and replaying
the disseminated messages can be easily launched.

12. 2.Expedite Message Authentication Protocol
• A Trusted Authority (TA): Providing anonymous certificate and
Distributing secret keys to all OBUs in the network.
• Roadside units (RSUs): which are fixed units distributed all over
the network. The RSUsCan communicate securely with the TA.
• On-Board Units (OBUs): which are embedded in vehicles? OBUs
can communicate either with other OBUs through V2V
communications or with RSUs through V2I communications.

13. 3.Security Analysis
– Hash Chain Values
• The values of the hash chains are continuously used in the revocation
processes, and hence, the TA can consume all the hash chain values.
– Resistance of forging attacks
• Find the TA secret key and signature. To the revocation check and
TA message and signature are unforgetable.

14. CENTRALIZED SERVER

15. FIRST MOBILE HOST
•

16. SECOND MOBILE HOST

17. THIRD MOBILE HOST
•

18. SENDING TO SERVER

19. RESPONSE SEND TO MIS

20. CENTRALIZED SERVER
REPORT

21. CONCLUSION
• A location based query solution that employs two protocols that
enables a user to privately determine and acquire location data.

22. REFERENCES
[1] (2011, Jul. 7) Openssl [Online]. Available:
http://www.openssl.org/
[2] M. Bellare and S. Micali, “Non-interactive oblivious transfer and
applications,” in Proc. CRYPTO, 1990, pp. 547–557.
[3] A. Beresford and F. Stajano, “Location privacy in pervasive
computing,”IEEE Pervasive Comput., vol. 2, no. 1, pp. 46–55, Jan.–
Mar.2003.