• Journal of KIISE:Computing Practices and Letters
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• v.16 no.8
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• pp.853-862
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• 2010

As the mobile device and broadband wireless internet such as WiBro, HSDPA is widely spreading, various types of advertisement and services based on personal location information can be provided. However, with convenience supported by these services, it is possible to be increased an invasion of privacy such as personal location and moving pattern. In this paper, we analysis an essential element for protection of privacy related on location information in mobile environment and propose location privacy protocol for managing location privacy self-control. And we design and implementation prototype of location privacy self-control system which is able to manage user's location privacy condition oneself using the proposed location privacy protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8B
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• pp.929-938
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• 2011

The setting algorithm of cloaking region using dummy which is proposed in this paper solves the problem which counts the building with duplication that exists in several cells of Privacy Grid by adding the building grouping item to the index structure of the existing Privacy Grid, and by increasing K value after searching the contiguous cells in the comer of each building, the exposure problem of private location information due to the minimum cloaking region setting of the existing GBC is solved. In addition, this paper reduces the searching time of K value by setting smaller cloaking region than Privacy Grid and GBC with dummy K before expanding cloaking region and strengthens the location information protection of users using dummy K.

• Journal of Information Processing Systems
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• v.16 no.1
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• pp.96-112
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• 2020

Solving the disclosure problem of sensitive information with the k-nearest neighbor query, location dummy technique, or interfering data in location-based services (LBSs) is a new research topic. Although they reduced security threats, previous studies will be ineffective in the case of sparse users or K-successive privacy, and additional calculations will deteriorate the performance of LBS application systems. Therefore, a model is proposed herein, which is based on geohash-encoding technology instead of latitude and longitude, memcached server cluster, encryption and decryption, and authentication. Simulation results based on PHP and MySQL show that the model offers approximately 10× speedup over the conventional approach. Two problems are solved using the model: sensitive information in LBS application is not disclosed, and the relationship between an individual and a track is not leaked.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.5
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• pp.439-444
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• 2016

This paper proposes the technique to protect the privacy of those who uses Smart Tourism Service based on location. The proposed privacy protection technique (1) generates a shared private key, OTK(One Time Key) without information exchanging Users with a Tourism Server and provides Users and a Tourism Server with message confidentiality by encrypting data with the key, (2) concatenates users' ID, login time(timestamp), and randomly-generated nonce, generates OTK by hashing with a hash function, encrypts users' location information and query by using the operation of OTK and XOR and provides Users and a Tourism Server with message confidentiality by sending the encrypted result. (3) protects a message replay attack by adding OTK and timestamp. Therefore, this paper not only provides data confidentiality and users' privacy protection but also guarantees the safety of location information and behavior pattern data.

• Spatial Information Research
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• v.20 no.5
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• pp.57-66
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• 2012

Recent development in wireless communication technology like GPS as well as mobile equipments like PDA and cellular phone makes location-based services (LBSs) popular. However, because users request a query to LBS servers by using their exact locations while moving on the road network, users' privacy may not be protected in the LBSs. Therefore, a mechanism for users' privacy protection is required for the safe and comfortable use of LBSs by mobile users. For this, we, in this paper, propose a road network distance based cloaking scheme supporting user privacy protection in location-based services. The proposed scheme creates a cloaking area by considering road network distance, in order to support the efficient and safe LBSs on the road network. Finally, we show from our performance analysis that our cloaking scheme outperforms the existing cloaking scheme in terms of cloaking area and service time.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.8
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• pp.606-610
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• 2009

In Location-Based Service (LBS), a scheme to hide the exact locations of users is required for privacy protection, In this paper, we propose a grid-based cloaking method considering K-anonymity and L-diversity. For this, our method creates a minimum cloaking region by finding L number of buildings (L-diversity) and then finding number of users (K-anonymity). Especially, we use a effective filtering method for generating the minimum cloaking region in a fast way. Finally, we show from a performance analysis that our cloaking method outperforms the existing method, in terms of query processing time based on the size of cloaking regions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.211-214
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• 2009

This paper describes a location privacy control system. Also, we propose a model of location privacy control for national usage and system. This research is applicable to location privacy protection in commercial location-based services in wireless telecommunications, T-Money transtoration card system, GIS platform and provide system of variety service.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.8
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• pp.2827-2848
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• 2021

Mobile Crowdsourcing (MCS) has become an emerging paradigm evolved from crowdsourcing by employing advanced features of mobile devices such as smartphones to perform more complicated, especially spatial tasks. One of the key procedures in MCS is to collect answers from mobile users (workers), which may face several security issues. First, authentication is required to ensure that answers are from authorized workers. In addition, MCS tasks are usually location-dependent, so the collected answers could disclose workers' location privacy, which may discourage workers to participate in the tasks. Finally, the overhead occurred by authentication and privacy protection should be minimized since mobile devices are resource-constrained. Considering all the above concerns, in this paper, we propose a lightweight and privacy-preserving answer collection scheme for MCS. In the proposed scheme, we achieve anonymous authentication based on traceable ring signature, which provides authentication, anonymity, as well as traceability by enabling malicious workers tracing. In order to balance user location privacy and data availability, we propose a new concept named current location privacy, which means the location of the worker cannot be disclosed to anyone until a specified time. Since the leakage of current location will seriously threaten workers' personal safety, causing such as absence or presence disclosure attacks, it is necessary to pay attention to the current location privacy of workers in MCS. We encrypt the collected answers based on timed-release encryption, ensuring the secure transmission and high availability of data, as well as preserving the current location privacy of workers. Finally, we analyze the security and performance of the proposed scheme. The experimental results show that the computation costs of a worker depend on the number of ring signature members, which indicates the flexibility for a worker to choose an appropriate size of the group under considerations of privacy and efficiency.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.4
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• pp.679-691
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• 2020

In the future, 5G technology will become the core infrastructure driving the 4th industrial era. For intelligent super-convergence service, it will be necessary to collect various personal information such as location data. If a person's high-precision location information is exposed by a malicious person, it can be a serious privacy risk. In the past, various approaches have been researched through encryption and obfuscation to protect location information privacy. In this paper, we proposed a new technique that enables statistical query and data analysis without exposing location information. The proposed method does not allow the original to be re-identified through polynomial-based transform processing. In addition, since the quality of the original data is not compromised, the usability of positioning big data can be maximized.

• Journal of Korea Spatial Information System Society
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• v.11 no.3
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• pp.19-30
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• 2009

Recent development in wireless communication technology and mobile equipment like PDA, cellular phone and GPS makes location-based services (LBSs) popular. However, because, in the LBSs, users continuously request a query to LBS servers by using their exact locations, privacy information could be in danger. Therefore, a mechanism for users' privacy protection is required for the safe and comfortable use of LBSs by mobile users. For this, this paper propose a grid-based cloaking area creation scheme supporting continuous LBSs. The proposed scheme creates a cloaking area rapidly by using grid-based cell expansion to efficiently support the continuous LBSs. In addition, to generate a cloaking area which makes the exposure probability of a mobile user to a minimum, we compute a privacy protection degree by granting weights to mobile users. Finally, we show from a performance analysis that our cloaking scheme outperforms the existing cloaking schemes, in terms of service time, privacy protection degree.