• Journal of Digital Convergence
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• v.12 no.2
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• pp.243-248
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• 2014

The demand for messenger service goes on growing rapidly with widespread use of smartphones. Generally, the smartphone messenger provides group communication functions in which users can make the group and communicate with each other. In the mobile meeting, the attendees can participate in the meeting with use of smartphone messengers wherever they are. To make the mobile meeting put to practical use, the mobility and privacy should be ensured to attendees. To satisfy the mobility requirement, the user which is not belong to the group members should not be able to participate in the meeting. To ensure the privacy requirement, the attendees should have not to repudiate the meeting results. In this study, the mobile meeting authentication scheme is proposed which provides mobility and privacy. The proposed scheme consists of meeting group creation, group key generation, group signature and verification protocols. All attendees should have to participate in the signature verification because it is based on the challenge-response type protocol. Thus, it's not possible to collude with malicious attendees to change the meeting results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.374-379
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• 2005

In the most of medical institution medical information is totally stored in a database and many number of researchers and staffs of the hospital access these information anytime. This can be caused patient's privacy to be violated. Introducing a tool for security should be considered as one of the most important requirement especially in the case that today's medical information service expands into an integrated one. In this paper we review the matters of security threat on a medical information system and propose a secure medical information service model equipped on mobile device such as PDA. Also we propose a security architecture employing a digital signature mechanism to protect the personal information on the model. Proposed architecture can lead the doctor to diagnose with high responsibility, help to build a reliable medical information system. and through the signed data, we can get some useful information against medical strife.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.1
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• pp.166-183
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• 2013

It requires a lot of costs and manpower to manage an election. The electronic voting scheme can make the election system economic and trustful. The widespread use of smart phones causes mobile voting to be a major issue. The smart phone can be used as a mobile voting platform since it can carry out many services in addition to basic telephone service. To make mobile voting practical and trustful, we analyzed two subjects of study. Firstly, the way to make a biometric based mobile ID, which has legal binding forces. In mobile voting, user identification is accomplished on line since the voter should be able to vote wherever they go. The digital ID conducts a similar role to the need for a resident card. The user's identity is bound to the resident card legally. To bind the user's identity to the smart phone, we use USIM. Biometric recognition is also needed to authenticate the user, since the user cannot prove him or her on line face-to-face. The proposed mobile ID can be reissued by means of introducing a random secret value. Secondly, the mobile voting scheme is proposed where candidates can accept election results without doubt. The goal of an election is to select a leader among two or more candidates. Existing electronic voting schemes mainly focus on the study of ballot verification accomplished by voters. These approaches are not safe against collusion attacks where candidates and the election administration center are able to collude to fabricate election results. Therefore, a new type of voting and counting method is needed where candidates can directly take part in voting and counting stages. The biometric based multi-signature scheme is used to make the undeniable multi-signed ballot. The ballot cannot be verified without the help of all candidates. If candidates accept election results without a doubt, the fairness of the election is satisfied.

• The Journal of Korean Association of Computer Education
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• v.7 no.4
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• pp.61-66
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• 2004

Electronic commerce that use Mobile Phone according as the radio Internet develops rapidly and performance of Mobile Phone develops is activated. It is said that electronic commerce that use these Mobile Phone is M-Commerce. Also, the most important controversial point is data security or an user certification technology at these electronic commerce, there are research reactor WPKI and WTLS about this technology. However, when transmit message again after sign electronic documents in Mobile Phone, if do not encrypt, danger exists to be exposed to outside. Therefore, in this paper, designed system to encipher document that handle and handles user certification applying XML electronic sign technique in Mobile environment. Prevent of XML electronic sign in Mobile environment through this paper, and can stave off danger from outside by enciphering electronic sign document.

• Journal of Korea Multimedia Society
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• v.10 no.3
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• pp.373-380
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• 2007

In this paper we propose a new efficient authentication protocol that reduces overheads of computation for digital signature generation/verification on mobile devices in the Personal Area Network (PAN). In particular, we focus on eliminating the traditional public key operations on mobile devices without any assistance of a signature server. Moreover, the proposed protocol provides a simplified procedure for certificate status management to alleviate communication and computational costs on mobile devices in the PAN.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5537-5555
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• 2017

Having the characteristics of unlinkability, anonymity, and unforgeability, blind signatures are widely used for privacy-related applications such as electronic cash, electronic voting and electronic auction systems where to maintain the anonymity of the participants. Among these applications, the blinded message is needed for a certain purpose by which users delegate signing operation and communicate with each other in a trusted manner. This application leads to the need of proxy blind signature schemes. Proxy blind signature is an important type of cryptographic primitive to realize the properties of both blind signature and proxy signature. Over the past years, many proxy blind signature algorithms have been adopted to fulfill such task based on the discrete logarithm problem (DLP) and the elliptic curve discrete log problem (ECDLP), and most of the existing studies mainly aim to provide effective models to satisfy the security requirements concerning a single blinded message. Unlike many previous works, the proposed scheme applies the signcryption paradigm to the proxy blind signature technology for handling multiple blinded messages at a time based on elliptic curve cryptography (ECC). This innovative method thus has a higher level of security to achieve the security goals of both blind signature and proxy signature. Moreover, the evaluation results show that this proposed protocol is more efficient, consuming low communication overhead while increasing the volume of digital messages compared to the performance from other solutions. Due to these features, this design is able to be implemented in small low-power intelligent devices and very suitable and easily adoptable for e-system applications in pervasive mobile computing environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.6
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• pp.1416-1422
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• 2010

Various other platforms have appeared due to the abolishment of WIPI requirement and increased problems related with hacking and security. Since levels consisting of these platforms are composed of various APIs (Application Programming Interfaces) which are not standardized, other ways must be considered to protect data which are transferred using XML formats. Therefore, XML encryption API and XML digital signature API for data protection and certification, which are both responsible to define mark-up languages for XML encryption and digital signature respectively, were designed in this paper. The simulation system which played the role of the server and client between two terminal units was realized to validate the APIs.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.2
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• pp.275-284
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• 2014

Recently, the combination of mobile and NFC aroused great momentum for Activation of NFC services market. Especially, mCoupon service using NFC has been utilized in a variety consumer marketing. However, mCoupons differ significantly from paper-based coupons because unprotected data can be easily copied or modified without significant cost by anyone. A high number of uncontrolled copies of coupons can result in a significant loss. In this paper, we proposed a light-weight signature scheme that is protected against illegal use in nfc mobile payment environment to using limited resources.

• Journal of Broadcast Engineering
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• v.14 no.3
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• pp.288-298
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• 2009

In this paper, we propose a scheme to associate content-based video signature with Universal Content Identifier (UCI) system of broadcast content for copyright identification and management. Note that content-based video signature can identify a previously distributed content since it is directly extracted from content itself without allocation process of identifier such as UCI. Thus, we design the schema of UCI application metadata, which provides a video signature in order to consistently maintain a systemic link between UCI and the video signature. Also, we present the scenarios of copyright identification, management and additional service, which are based on transmission and management mechanism of video signature with UCI identification system.

• The Journal of Society for e-Business Studies
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• v.10 no.1
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• pp.121-134
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• 2005

The MANET has many problems in security despite of its many advantages such as supporting the mobility of nodes, independence of the fixed infrastructure, and quick network establishment. In particular, in establishing security, the traditional certification service has many difficult problems in applying to the MANET because of its safety, expandability, and availability. In this paper, a secure and effective distributed certification service method was proposed using the Secret Sharing scheme and the Threshold Digital Signature scheme in providing certification services in the MANET. In the proposed distributed certification service, certain nodes of relatively high safety among the mobile nodes consisting of the MANET, were set as privileged nodes, from which the process of issuing a certification started. The proposed scheme solved problem that the whole network security would be damaged by the intrusion to one node in the Centralized Architecture and the Hierarchical Architecture. And it decreased the risk of the exposure of the personal keys also in the Fully Distributed Architecture as the number of the nodes containing the partial confidential information of personal keys decreased. By the network simulation, the features and availability of the proposed scheme was evaluated and the relation between the system parameters was analyzed.