• Bulletin of the Korean Mathematical Society
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• v.50 no.6
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• pp.1799-1816
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• 2013

Privacy preserving multiset union (PPMU) protocol allows a set of parties, each with a multiset, to collaboratively compute a multiset union secretly, meaning that any information other than union is not revealed. We propose efficient PPMU protocols, using multiplicative homomorphic cryptosystem. The novelty of our protocol is to directly encrypt a polynomial by representing it by an element of an extension field. The resulting protocols consist of constant rounds and improve communication cost. We also prove the security of our protocol against malicious adversaries, in the random oracle model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4680-4700
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• 2015

Broadcast encryption is an efficient way to distribute confidential information to a set of receivers using broadcast channel. It allows the broadcaster to dynamically choose the receiver set during each encryption. However, most broadcast encryption schemes in the literature haven't taken into consideration the receiver's privacy protection, and the scanty privacy preserving solutions are often less efficient, which are not suitable for practical scenarios. In this paper, we propose an efficient dynamic anonymous broadcast encryption scheme that has the shortest ciphertext length. The scheme is constructed over the composite order bilinear groups, and adopts the Lagrange interpolation polynomial to hide the receivers' identities, which yields efficient decryption algorithm. Security proofs show that, the proposed scheme is both secure and anonymous under the threat of adaptive adversaries in standard model.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.711-720
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• 2020

This research aims to analyze the factors affecting the acceptance of social commerce, including performance expectancy, effort expectancy, social support, facilitating conditions, hedonic motivation, habitability, price saving orientation, and privacy concerns using the Unified Theory of Acceptance and Use of Technology (UTAUT2). UTAUT2 has been examined and modified in various contexts. The research model studies the acceptance and use of technology in the context of customers. This study adopts a quantitative method using the partial least squares regression (PLS) approach involving 244 respondents. The respondents are users of social commerce in Indonesia. The result of this research indicates that social influence, facilitating conditions, hedonic motivation, habit, price value orientation, and privacy concerns have a significant effect on behavioral intention. On the other hand, performance expectancy and effort expectancy does not affect behavioral intention. Furthermore, price value has a significant effect on social commerce user behavior. Lastly, facilitating conditions and habits does not affect social commerce user behavior. This research contributes to the development of theory by examining an additional variable, which is privacy concern. This study is significant since social media and social commerce have grown exponentially nowadays. Implications of the results for the development of the theory (UTAUT2) and practice are discussed in the article.

• Journal of Information Technology Services
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• v.17 no.3
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• pp.157-169
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• 2018

This study aims to examine the factors influencing user attitude toward Smart Home service as the demand of Smart Home service is increasing and it somewhat involves privacy risk. To this end, the research model includes five independent variables, trust in service provider, perceived privacy risk, self efficacy, interpersonal influence, and external influence, influencing the attitude toward Smart Home service. So, this study aims to analyze which variable is the most critical and influential among the five factors and suggest the direction of Smart Home industries. This study first reviews the literature on Smart Home services and describes its Korean situation. Data were collected from residents living in a smart apartment complex. The results show that (1) users have a very positive attitude toward Smart Home service in total, (2) trust in service providers, self efficacy, and interpersonal influence positively impact user attitude toward Smart Home service and interpersonal influence is the most influential variable, however, (3) perceived privacy risk and external influence dose not significantly impact it. These results imply that the role of service providers, self efficacy, and interpersonal influence are important factors on the user attitude toward Smart Home service. Finally, the study's findings and limitations are discussed and potential avenues for future research are suggested.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2717-2722
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• 2013

Sophisticated business intelligent software and personalized web services help collecting and mining huge amounts of personal information. This increase in digitalized personal information and advances in Internet technologies poses new challenges to consumers' information privacy. Based on the identified concept of information privacy concerns (IPC), this study additionally explores the interrelationships among consumers' individual characteristics(self-efficacy, digital literacy, customer alienation), customer satisfaction and intention to buy in e-commerce process. Academically, this study extends IPC to an empirical research model by identifying the conceptualization and organization of IPC. Moreover, practically, e-commerce providers can develop how to relieve IPC of online consumers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1229-1248
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• 2016

With the feature of convenience and low cost, remote healthcare monitoring (RHM) has been extensively used in modern disease management to improve the quality of life. Due to the privacy of health data, it is of great importance to implement RHM based on a secure and dependable network. However, the network connectivity of existing RHM systems is unreliable in disaster area because of the unforeseeable damage to the communication infrastructure. To design a secure RHM system in disaster area, this paper presents a Secure VANET-Assisted Remote Healthcare Monitoring System (SVC) by utilizing the unique "store-carry-forward" transmission mode of vehicular ad hoc network (VANET). To improve the network performance, the VANET in SVC is designed to be a two-level network consisting of two kinds of vehicles. Specially, an innovative two-level key management model by mixing certificate-based cryptography and ID-based cryptography is customized to manage the trust of vehicles. In addition, the strong privacy of the health information including context privacy is taken into account in our scheme by combining searchable public-key encryption and broadcast techniques. Finally, comprehensive security and performance analysis demonstrate the scheme is secure and efficient.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.29-40
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• 2009

The development of information technology such as the internet has brought about rapidly changes the old medical technology, e-Healthcare has been to raise social issue. The e-Healthcare which new turning point of paradigm in the medical information develops the medical policy in Korea and the technology, the prospective of reverse engineering in internet environment is incurring problems such as distribution of critical information and invasion and infringement of privacy, etc. In this research, we suggest the Role Based Access Control System, HPIP-e-Healthcare Privacy Information Protection, for solving above problem. The HPIP is composed 4 mechanisms such as Consolidate User Identity, Hospital Authorization, Medical Record Access Control, Patient Diagnosis and we are also prototyping the HPIP for feasible approach in the real computing environment.

• Journal of Information Processing Systems
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• v.13 no.6
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• pp.1613-1627
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• 2017

The concept of the Internet of Things (IoT) enables physical objects or things to be virtually accessible for both consuming and providing services. Undue access from irresponsible activities becomes an interesting issue to address. Maintenance of data integrity and privacy of objects is important from the perspective of security. Privacy can be achieved through various techniques: password authentication, cryptography, and the use of mathematical models to assess the level of security of other objects. Individual methods like these are less effective in increasing the security aspect. Comprehensive security schemes such as the use of frameworks are considered better, regardless of the framework model used, whether centralized, semi-centralized, or distributed ones. In this paper, we propose a new semi-centralized security framework that aims to improve privacy in IoT using the parameters of trust and reputation. A new algorithm to elect a reputation coordinator, i.e., ConTrust Manager is proposed in this framework. This framework allows each object to determine other objects that are considered trusted before the communication process is implemented. Evaluation of the proposed framework was done through simulation, which shows that the framework can be used as an alternative solution for improving security in the IoT.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.2
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• pp.13-24
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• 2006

We consider a privacy-preserving cooperative computation protocol evaluating a beneficial function of all participants' secret inputs, such that each party finally holds a share of the function output. We propose a practical privacy-preserving cooperative computation protocol for solving the linear system of equations problem md the linear least-squares problem. Solutions to these problems are widely used in many areas such as banking, manufacturing, and telecommunications. Our multi-party protocol is an efficiently extended version of the previous two-party model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.1
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• pp.323-342
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• 2021

Personal health records (PHRs) is an electronic medical system that enables patients to acquire, manage and share their health data. Nevertheless, data confidentiality and user privacy in PHRs have not been handled completely. As a fine-grained access control over health data, ciphertext-policy attribute-based encryption (CP-ABE) has an ability to guarantee data confidentiality. However, existing CP-ABE solutions for PHRs are facing some new challenges in access control, such as policy privacy disclosure and dynamic policy update. In terms of addressing these problems, we propose a privacy protection and dynamic share system (PPADS) based on CP-ABE for PHRs, which supports full policy hiding and flexible access control. In the system, attribute information of access policy is fully hidden by attribute bloom filter. Moreover, data user produces a transforming key for the PHRs Cloud to change access policy dynamically. Furthermore, relied on security analysis, PPADS is selectively secure under standard model. Finally, the performance comparisons and simulation results demonstrate that PPADS is suitable for PHRs.