• Journal of KIISE
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• v.43 no.10
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• pp.1154-1164
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• 2016

To prevent the use of one's smartphone by another user, the authentication checks the owner in several ways. However, whenever the owner does use his/her smartphone, this authentication requires an unnecessary action, and sometimes he/she finally decides not to use an authentication method. This can cause a fatal problem in the smartphone's security. We propose a sustainable android platform-based authentication mode to solve this security issue and to facilitate secure authentication. In the proposed model, a smartphone identifies the current situation and then performs the authentication. In order to define the risk of the situation, we conducted a survey and analyzed the survey results by age, location, behavior, etc. Finally, a demonstration program was implemented to show the relationship between risk and security authentication methods.

• Journal of KIISE
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• v.43 no.11
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• pp.1259-1269
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• 2016

In order to block the access of the information in the smartphone of a user by other users, it is checked if the current user is the owner or not in the smartphone authentication process, whenever a user begins to use a smartphone. This makes smartphone users in front of frequent smartphone authentications, which leads significant inconvenience to them. Because of such inconvenience, users tend not to use the smartphone authentication anymore. Finally, their smartphones become very vulnerable against malicious access. This paper proposes a progressive authentication method on the android-platform in order to solve the problem described above. With the proposed method, smartphones can identify relevant risks based on users' past experiences and determine whether an authentication is needed. Because authentication occurs only when the identified risk level is high, it can achieve both a high-level of security in the high-level risk situation and user convenience in the low-level risk situation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.1
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• pp.248-268
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• 2018

The performance of smartphone applications are usually constrained in user interactions due to resource limitation and it promises great opportunities to improve the performance by exploring the smartphone built-in and embedded sensing techniques. However, heterogeneity in techniques, semantic gap between sensor data and usable context, and complexity of contextual situations keep the techniques from seamless integration. Relevant studies mainly focus on feasibility demonstration of emerging sensing techniques, which rarely address both general architectures and comprehensive technical solutions. Based on a proposed functional model, this investigation provides a general architecture to deal with the dynamic context for context-aware automation and decision support. In order to take advantage of the built-in sensors to improve the performance of mobile applications, an ontology-based method is employed for context modelling, linguistic variables are used for heterogeneous context presentation, and semantic distance-based rule matching is employed to customise functions to the contextual situations. A case study on mobile application authentication is conducted with smartphone built-in hardware modules. The results demonstrate the feasibility of the proposed solutions and their effectiveness in improving operational efficiency.

• Journal of the Korea Society of Computer and Information
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• v.19 no.10
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• pp.99-106
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• 2014

In this paper, we analyze weaknesses of the biometrics-based user authentication scheme proposed by An. The result of analysis An's authentication scheme by the login success scenario proposed in this paper, if the attacker successes to get user's random number, he/she can pass user authentication phase of the legal server. Also the biometrics guessing scenario proposed in this paper shows the legal user's the biometric information is revealed in lost smart card. Since An's authentication scheme submit user ID and biometrics in plain text to the server, it is very vulnerable to inner attack and it is not provide the user anonymity to the server as well as the one to the third by user ID in plain text. Besides An's authentication scheme is contextual error too, due to this, it has weakness and so on that it did not check the validity of the smart card holder.

• Korean journal of communication and information
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• v.62
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• pp.179-199
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• 2013

This study is aimed to draw the meaning and possibility of political participation of the SNS users through a phenomenological analysis of participation and awareness of authentication shot for vote of the users. Especially, the reason for focusing on 'SNS vote authentication shot' is because the creative imagination of the users and the meaning and possibility of collective intelligence are drew while citizens are participating in political activities for themselves. Theory resources are based on technical imagination of Vil$\acute{e}$m Flusser that is concerned with users and political practice in the New Media Era, creative imaginer and discussions of collective intelligence of Pierre L$\acute{e}$vy. Based on these theoretical discussions, it is aimed to select the SNS users experienced in authentication shot for the by-election for mayor of Seoul in 26. Oct. 2011 and to use phenomenological analysis model on materials collected after in-depth interview. The researchers take contextual circumstance into consideration for experiences of study participants sticking to SNS users' opinions and intersubjectivity and approach prejudice of their experiences to untouched structure of phenomenon and meaning. It is because a phenomenological study exploring "the own meaning of 'die Sachen'" is 'strict study' and method focusing on the political participation of SNS users itself.

• Journal of Platform Technology
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• v.9 no.1
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• pp.46-57
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• 2021

Recently, research has been actively conducted to utilize blockchain technology in various fields. In particular, blockchain-based smart contracts are applied to various automation systems that require reliability as they have the characteristics of recording data in a distributed ledger environment to verify the integrity and validity of data. However, blockchain does not provide data access control and information security because data is shared among network participants. In this paper, we propose a user dynamic access control mechanism utilizing smart contracts in blockchain environments. The proposed mechanism identifies the user's contextual information when accessing data, allocating the user's role and dynamically controlling the data access range. This can increase the security of the system and the efficiency of data management by granting data access dynamically at the time of user authentication, rather than providing the same services in roles assigned to each user group of the network system. The proposed mechanism is expected to provide flexible authentication capabilities through dynamic data access control by users to enhance the security of data stored within blockchain networks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.2
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• pp.125-137
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• 2007

This paper proposes a new scheme to provide the location privacy of sources in Wireless Sensor Networks (WSNs). Because the geographical location of a source sensor reveals contextual information on an 'event' in WSN, anonymizing the source location is an important issue. Despite abundant research efforts, however, about data confidentiality and authentication in WSN, privacy issues have not been researched well so far. Moreover, many schemes providing the anonymity of communication parties in Internet and Ad-hoc networks are not appropriate for WSN environments where sensors are very resource limited and messages are forwarded in a hop-by-hop manner through wireless channel. In this paper, we first categorize the type of eavesdroppers for WSN as Global Eavesdropper and Compromising Eavesdropper. Then we propose a novel scheme which provides the anonymity of a source according to the types of eavesdroppers. Furthermore, we analyze the degree of anonymity of WSN using the entropy-based modeling method. As a result, we show that the proposed scheme improves the degree of anonymity compared to a method without any provision of anonymity and also show that the transmission range plays a key role to hide the location of source sensors.