• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.5
• /
• pp.1717-1732
• /
• 2015

The widespread use of location-based services (LBSs), which allows untrusted service provider to collect large number of user request records, leads to serious privacy concerns. In response to these issues, a number of LBS privacy protection mechanisms (LPPMs) have been recently proposed. However, the evaluation of these LPPMs usually disregards the background knowledge that the adversary may possess about users' contextual information, which runs the risk of wrongly evaluating users' query privacy. In this paper, we address these issues by proposing a generic formal quantification framework,which comprehensively contemplate the various elements that influence the query privacy of users and explicitly states the knowledge that an adversary might have in the context of query privacy. Moreover, a way to model the adversary's attack on query privacy is proposed, which allows us to show the insufficiency of the existing query privacy metrics, e.g., k-anonymity. Thus we propose two new metrics: entropy anonymity and mutual information anonymity. Lastly, we run a set of experiments on datasets generated by network based generator of moving objects proposed by Thomas Brinkhoff. The results show the effectiveness and efficient of our framework to measure the LPPM.

• Journal of the HCI Society of Korea
• /
• v.12 no.2
• /
• pp.13-19
• /
• 2017

Various life-logging based on cloud service have developed social network according to the advanced technology of smartphone and wearable device. Daily digital life on social networks has been shared information and emotion and developed new social relationships. Recent life-logging has required social relationships beyond extension of personal memory and anonymity for privacy protection. This study is to determine social network group by using life-logging data obtained in daily lives and to categorize emotion behavior with anonymity guarantee. Social network group was defined by grouping similar representative emotional behavior. The public's patterns and trends was able to be inferred by analyzing representative emotion and behavior of the social groups network.

• Journal of Digital Convergence
• /
• v.18 no.1
• /
• pp.45-52
• /
• 2020

Online rumor creates psychological stress and image loss for victims. Prior studies related to online rumor did not consider the online environmental factor, despite the fact that online rumor occurs in the online space. Therefore, this study tried to investigate the influence of online characteristics on online rumor. This study considered perceived anonymity, lack of social presence, and perceived dissemination as online characteristics. We established and demonstrated a research model in which online characteristics affect online rumor behavior through attitude toward online rumor. This study obtained the sample of 201 social network users based on the survey and verified the research model using PLS tool. The results provided that perceived anonymity and perceived dissemination influenced online rumor behavior through attitude toward online rumor. On the other hand, lack of social presence was not significant. The findings of this study provide the fact that an individual's online rumor behavior can be caused by online characteristics. This study suggests that we pay attention to the role of perceived anonymity and perceived dissemination for online rumor behavior.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.25 no.3
• /
• pp.493-500
• /
• 2015

Personal information exposed in the Internet is increasing by the public data opening and sharing, vitalization of SNS(Social Network Service) and growth of information shared between users. Exposed personal information in the Internet can infringe upon targeted users using linkage attack or background attack. To prevent these attack De-identification models were appeared a few years ago. The 'k-anonymity' has been introduced in the first place, and the '${\ell}$-diversity' and 't-closeness' have been followed up as solutions, and diverse algorithms have been being suggested for performance improvement nowadays. However, industry or public sectors actually needs a whole solution as a system for the de-identification process rather than performance of the de-identification algorithm. This paper explains a way of de-identification techique for 'k-anonymity', '${\ell}$-diversity', and 't-closeness' algorithm using QI(Quasi-Identifier) grouping method in the relational database.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.12C
• /
• pp.1021-1028
• /
• 2008

In a network environment, when a user requests a server's service, a remote user authentication system using smart cards is a very practical solution to validate the eligibility of a user and provide secure communication. In these authentication schemes, due to fast progress of networks and information technology, most of provided services are in multi-server environments. However, there are no studies in multi-server authentication schemes using smart cards providing mutual anonymity so far. In this paper, we propose a novel user authentication scheme using smart cards providing mutual authentication and mutual anonymity for multi-server environments. Our proposed scheme achieves the low-computation requirement for smart cards and a user can use permitted various services in eligible servers by only one registration. Also, this scheme guarantees perfect mutual anonymity of participants.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.5
• /
• pp.394-402
• /
• 2021

Electronic voting systems have been widely used in many countries around the world since the mid-1990s. In recent years, studies have applied blockchain to existing electronic voting systems in order to provide reliability, fairness, and transparency for voters. This approach is highly useful as a technology that promotes decentralized citizen participation. However, the existing electronic voting systems using blockchain have not sufficiently considered anonymity. Lack of anonymity acts as an important constraint in cases of small- and medium-sized voting, which is often required in decentralized citizen participation. In this study, we propose a model that provides anonymity to a voting system using blockchain by applying the concept of the master node in Dash cryptocurrency. First, we define the differences in the requirements of the transfer and voting systems in blockchain. We propose a parallel and autonomous model and algorithm to provide anonymity in the blockchain-that is, a decentralized development environment. In addition, a discussion of security and the environment for the proposed model is described.

• Journal of Internet Computing and Services
• /
• v.7 no.5
• /
• pp.71-79
• /
• 2006

The GNUnet proposed a file encoding method by lKB block size to support anonymity of files and decentralizes encoded block to peers through unstructured model. but, the encoding and block decentralizing method with 600$\sim$700MB large multimedia file appeared two problems. First problem. it need addition R block and I block, which make about 4% of storage resource. Second problem, unstructured model added network load by broadcasting decentralizing method. This paper suggest variable encoding block size and structured model by block decentralizing solution. Suggested encoding method reduced block request supplementary block generation to 1% and network load by proposal structured model sending answer through dedicated peer to decentralize block.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.23 no.5
• /
• pp.1260-1269
• /
• 1998

We investigate here problems related to a subscriber authentication protocol in CDPD, and suggest an improved alternative. Associated with an anonymity of the subscriber, another method of generating the distributing alias is proposed other than the conventional approach initiated by an authentication server in this home network.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.5 no.3
• /
• pp.168-174
• /
• 2010

User authentication is an important requirement to provide secure network service. Therefore, many authentication schemes have been proposed to provide secure authentication, such as key agreement and anonymity. However, authority of scheme is limited to one's self. It is inefficient when authenticated users grant a certification to other users who are in an organization which has a hierarchical structure, such as a company or school. In this paper, we propose the first authentication scheme to use Attributes-Based Re-encryption that creates a certification to other users with specified attributes. The scheme, which has expanded from Rhee et al. scheme, has optimized computation performance on a smart card, ensuring the user's anonymity and key agreement between users and server.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.12
• /
• pp.6175-6189
• /
• 2019

To slove the security and efficiency problem of anonymous authentication in vehicular ad-hoc network (VANET), we adopt the bilinear pairing theory to propose an identity-based batch anonymous authentication scheme for VANET. The tamper-proof device in the on-board unit and the trusted authority jointly realize the anonymity of vehicle identity and the signature of messages, which further enhances the security of this scheme, as well as reduces the overhead of trusted authority. Batch authentication can improve the efficiency of anonymous authentication for VANET. Security and efficiency analyses demonstrate that this scheme not only satisfies such security properties as anonymity, non-forgeability and non-repudiation, but also has advantage in time and space complexity. Simulation results show that this scheme can achieve good performance in real-time VANET communication.