TOPIC: Methods to protect Location Privacy in Location Based Services.
The rapid development of wireless communications and mobile database technology promote the
extensive application of location based services, and provide a greatly convenience for people’s lives.
Users’ location information is stored with the service provider in order to deliver the services. Here user
location privacy security poses a potentially grave threat. Location privacy issues raised by such
applications have attracted more and more attention. It has become a research focus to find a balance
point between the location based highly sufficient services and users’ location privacy protection. Efforts
are being made in order to render the required location based services with minimal or no disclosure of
user information to the provider. Various methods are developed to preserve privacy in location based
services. Majority of the methods can be classified into 4 categories k-anonymity, encryption, cloaking
and addition of dummies. In this survey paper we present methods in these categories that address
varied privacy concerns.
Different papers are studied that implement location privacy. Various methods are proposed and
depending on the method they implement they are classified into 4 categories namely k-anonymity,
encryption, cloaking, addition of dummies.
K-anonymity: This is the process in which users’ identity is mixed with k-1 other users in the location.
Therefore user exact location cannot be identified.
Encryption: papers chosen in this category chiefly use blind signature. Blind signature is an encryption
scheme that allows a person to get a message signed by another party without revealing any
information about the message to the other party.
Addition of Dummy users: In this process, dummy users or dummy queries or dummy user movement
patterns are generated and sent to the service provider server. This helps in confusing the identity of a
user with the generated dummies.
Cloaking: cloaking is the process the hiding the information, such as the region in which user is located;
the speed or direction in which user is heading is hidden etc.
Classification scheme for our survey: explains models under each classification.
K-anonymity implementing a trusted third party, a distributed k-anonymity protocol that neither
trusts server nor trusts users, k-anonymity’s quality of service and query systems.
Encryption Anonymous authentication protocol using blind signature and ring signature,
homomorphic encryption, delinking anonymous IDs and real IDs by using blind signature and bilinear
Addition of Dummies Protecting trajectories by generating dummy trajectories, dummy user trigger
and dummy user generation algorithms, providing server with fake identities.
Cloaking a distributed spatial cloaking protocol, Grid based cloaking algorithm, cloaking user speed
and heading direction.
Much research is being carried out on how to protect location privacy without compromising the
efficiency and accuracy of delivered services.
Papers related to k-anonymity:
Paper proposes a distributed k-anonymity protocol, where the protocol requires neither a single
trusted server nor trust in all users. The protocol has multiple servers each knowing the location of only
a subset of users, with the subsets being disjoint. Now to implement the user preferred k-anonymity,
the users will not know the number of people in their region but only know whether the region has at
least k people.
Paper addresses privacy concerns in augmented reality by developing an algorithm that uses both k-
anonymity and pseudo-anonization. A trusted third party is used to implement this. For a given message
it deals with identifying k-1 other messages with which this message can be anonymized with, and then
forwards it to external LBS providers.
Paper analyzes on k-anonymity’s quality of service and query systems. It analyses on existing
questions of location privacy protection system in Location based services at the present time. Some
solutions have be proposed to deal with location privacy problem.
Papers related to Cloaking:
Paper shows that by combining consecutive location data including speed heading direction or cloaked
locations, an adversary can obtain more accurate estimation of the actual location. To prevent interference
attacks, cloaking either speed or direction alone is generally not sufficient. This paper proposes a solution
to prevent such interferences by cloaking both speed and direction.
Papers proposes a cloaking algorithm for privacy protection in LBSs. This cloaking algorithm can
support both k-anonymity and l-diversity.It first creates a minimum cloaking region by finding l
building(l-diversity) and then finds k users(k-anonymity).
Paper proposes a spatial cloaking protocol satisfied k-anonymity, to generate a cloak area. This
protocol is based on the computation of the left-up and right-bottom of a minimum rectangle area that
covers LBS initiator and its k-1 companions, without direct transmission of users’ location.
Papers related to Dummies Generation:
Paper argues that it is important to protect the trajectories of the users since if the trajectory of a user is
identified then his locations can be exposed. It proposes two schemes random and rotation pattern
schemes to generate dummy consistent movements patterns in long run.
Paper proposes a method that uses identity diffusion generator. Users have the ability to specify his
privacy requirements. This model achieves privacy by providing the server with fake identities and also
generating a number of fake queries with the real query information, hidden when and where it was
Paper addresses the privacy in sparse environments. In sparse environment, the association risk
between users and their location increases. Therefore it develops an algorithm that generates dummy
users, it decides whether to generate dummy users or not depending on the users available in that region.
Papers related to encryption:
Paper proves that a protocol, proposed by Qi, that uses blind signature to generate authorized
anonymous ID that replaces the real ID of a mobile device will not delete the linkability between both the
IDs. It proposes an improved registration protocol that adapts the same cryptographic technique based on
Paper proposes a model that uses oblivious transfers and homomorphic encryption. In the proposed
no trusted third party is needed and user location and usage information can be protected by using
oblivious transfer twice. In the oblivious transfer protocols the senders sends some information to the
receiver, while knows nothing about what is sent. Blind signature method is used in oblivious transfer.
Paper proposes an anonymous authentication protocol to protect location privacy. In this protocol, the
service providers use blind signature to generate an authorized anonymous ID for the user, and then the
user uses ring signature to mix the anonymous ID into a group of authorized IDs.
.Towards a distributed k-anonymity protocol for location privacy, GeZhong; Hengartner, U.;
Pervasive Computing and Communications, 2009.PerCom 2009. IEEE International Conference on
Digital Object Identifier: 10.1109/PERCOM.2009.4912774
Publication Year: 2009 , Page(s): 1 – 5
Securing location privacy in Augmented Reality, Aryan, A.; Singh, S.;
Industrial and Information Systems (ICIIS), 2010 International Conference on
Digital Object Identifier: 10.1109/ICIINFS.2010.5578714
Publication Year: 2010 , Page(s): 172 - 176
The location privacy protection research in location-based service ,Wenyan Zhang; Ximing Cui; Dengfeng Li;
Debao Yuan; Mengru Wang; Geoinformatics, 2010 18th International Conference on
Digital Object Identifier: 10.1109/GEOINFORMATICS.2010.5568118
Publication Year: 2010 , Page(s): 1 - 4
Preserving Privacy for Location-Based Services with Continuous Queries, Yiming Wang; Lingyu Wang; Fung,
B.C.M.; Communications, 2009.ICC '09. IEEE International Conference on
Digital Object Identifier: 10.1109/ICC.2009.5199361
Publication Year: 2009 , Page(s): 1 - 5
A Distributed Spatial Cloaking Protocol for Location Privacy, Huang Zhangwei; XinMingjun;
Networks Security Wireless Communications and Trusted Computing (NSWCTC), 2010 Second International
Conference on Volume: 2
Digital Object Identifier: 10.1109/NSWCTC.2010.243
Publication Year: 2010 , Page(s): 468 – 471
A New Grid-Based Cloaking Algorithm for Privacy Protection in Location-Based Services, Jungho Um;
Hyeongil Kim; Youngho Choi; Jaewoo Chang; High Performance Computing and Communications, 2009. HPCC
'09. 11th IEEE International Conference on
Digital Object Identifier: 10.1109/HPCC.2009.47
Publication Year: 2009 , Page(s): 362 - 368
Protecting Moving Trajectories with Dummies, Tun-Hao You; Wen-Chih Peng; Wang-Chien Lee;
Mobile Data Management, 2007 International Conference on
Digital Object Identifier: 10.1109/MDM.2007.58
Publication Year: 2007 , Page(s): 278 - 282
Protecting location privacy through Identity Diffusion, Lingyan Wang; Shaoen Wu;
Ultra Modern Telecommunications & Workshops, 2009.ICUMT '09. International Conference on
Digital Object Identifier: 10.1109/ICUMT.2009.5345458
Publication Year: 2009 , Page(s): 1 - 4
Location privacy in sparse environment, Heng Liu; Tiejun Wang; Ming Sun; Zhen Liu; Mingtian Zhou;
Advanced Computer Control (ICACC), 2010 2nd International Conference on
Volume: 4 Digital Object Identifier: 10.1109/ICACC.2010.5486958
Publication Year: 2010 , Page(s): 258 - 261
Improved mechanism for mobile location privacy, Jian Liao; Peiwei Huang;
Mobile Adhoc and Sensor Systems Conference, 2005. IEEE International Conference on
Digital Object Identifier: 10.1109/MAHSS.2005.1542875
Publication Year: 2005 , Page(s): 4 pp. - 810
An Improved Privacy Protocol in Location Based Service, Rong Cheng; Fangguo Zhang;
Information Engineering and Computer Science, 2009.ICIECS 2009. International Conference on
Digital Object Identifier: 10.1109/ICIECS.2009.5364986
Publication Year: 2009 , Page(s): 1 - 4
An Anonymous Authentication Protocol for Privacy Protection in Location Based Services , Yang Cao; Yan Li;
Hui Li; Xingfang Wang; Wireless Communications, Networking and Mobile Computing, 2008. WiCOM '08. 4th
International Conference on
Digital Object Identifier: 10.1109/WiCom.2008.1136
Publication Year: 2008 , Page(s): 1 – 5