• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.776-779
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• 2004

With the rapid progress of information technique, it is getting more difficult to protect information systems from cyber terrorism, because of bugs and vulnerabilities of software and the properties of cyberspace such as anonymity. furthermore cyber terror techniques are highly developed and complicated and their use for a malicious intent and a military purpose are increasing recently. Therefore a study of warfare attack technology on the cyber space is necessary for establishing trusted society and further national security. Specially, worms/viruses are becoming a more common occurrence on the cyber space. Also, The worm caused a great deal of damage to the large number of networks around the world in a very short period of time. Therefore, we will describe worms/viruses in the warfare attack technique in this paper.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.615-619
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• 2000

최근 급증하고 있는 인터넷 전자상거래의 가장 필수적인 부분이 전자지불 시스템이다. 전자적으로 처리되는 지불시스템은 사용자의 익명성 보장, 지불정보의 위조 및 재사용방지 등의 특징을 가지며, 거래 주체들간의 신뢰구축을 위한 상호 인증이 요구된다. 디지털 기술의 발달로 소액의 디지털 상품들이 많이 등장함에 따라 소액 상품만을 결제하기 위한 소액지불 시스템의 필요성이 증대되면서, Millicent, PayWord, MicroMint, MPTP 등의 소액 지불 시스템들이 연구되었으나 아직 효과적으로 사용되지 못하고 있다. 이러한 소액 지불 시스템의 경우에는 소비자가 한 상점에서 연속적인 거래를 수행하는데 따르는 비용을 먼저 생각해야 한다. 그 이유는 소액거래를 하는 대부분의 소비자들은 여러 개의 상품을 연속적으로 구입하는 경향을 가지기 때문이다. 또한 거래 주체간의 대금결제의 편의성을 도모하기위한 선불방식에 대한 연구가 필요하다. 그러나, 기존의 소액 지불 시스템들은 연속거래에 있어 제한적이거나 소비자의 신용을 기반으로 한 후불방식을 채택하고 있어 소비자의 화폐남용에 대한 자원낭비의 문제를 안고있다. 이에 본 논문에서는 Hash Chain을 이용하여 연속거래에 적합한 선불방식의 소액전자지불 시스템을 제안한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.6
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• pp.151-155
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• 2006

In 2005, Yong and Lee proposed a buyer-seller fingerprinting protocol using symmetric and commutative encryptions. They claimed that their protocol was practical and anonymous since they used symmetric and commutative encryptions. However, an attacker can get the content embedded with one or more honest buyers' fingerprints using man-in-the-middle attack. In this letter, we point out the weakness and propose methods for improving to their protocol.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.8
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• pp.1155-1160
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• 2013

The rapid growth of smart phones has made location-based services (LBSs) widely available. However, the use of LBS can raise privacy issues, as LBS can allow adversaries to violate the location privacy of users. There has been a considerable amount of research on preserving user location privacy. Most of these studies try to preserve location privacy by achieving what is known as location K-anonymity. In this paper, we propose a hierarchical clustering-based spatial cloaking algorithm for LBSs. The proposed algorithm constructs a tree using a modified version of agglomerative hierarchical clustering. The experimental results show, in terms of the ASR size, that the proposed algorithm is better than Hilbert Cloak and comparable to RC-AR (R-tree Cloak implementation of Reciprocal with an Asymmetric R-tree split). In terms of the ASR generation time, the proposed algorithm is much better in its performance than RC-AR and similar in performance to Hilbert Cloak.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.153-160
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• 2016

In this paper, we propose a system that tracks the position of the passengers and sailors using a Bluetooth-based Beacon in the ship. The position of the tracking passengers, sometimes fatal emergencies of the rescue team, such as the sinking of the ship is utilized in order to efficiently and quickly rescue the passengers, and the collected data can be utilized additionally by grasping the flow of human traffic patterns. The system proposed in this paper, install MAC data acquisition called AP (Access Point) for each cabin, and in the installed AP retrieves Tag of the information provided to the passenger and collected. A Tag has only its own MAC Address to the privacy, no user information is not collected. All data communication by sending and receiving MAC Address was only to ensure anonymity.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1551-1560
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• 2016

With the advancement of wearable devices and wireless body are networks, smart healthcare systems based on such technologies have been emerging to effectively monitor patient health and disease progression. In order to implement viable smart healthcare systems, the security and privacy of patient's personal health information must be considered. Yang et al. proposed a privacy-preserving authentication scheme using key-insulation technique for remote health monitoring system, however, key-insulation technique is not properly adapted to their scheme which in turn causes a security pitfall contrary to their assertions. Besides, Yang et al.'s scheme does not guarantee user anonymity against healthcare service provider. Therefore, in this paper, we discuss the security concerns for Yang et al.'s scheme and present an improved anonymous authentication scheme.

• The KIPS Transactions:PartC
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• v.10C no.7
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• pp.867-878
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• 2003

In thls Paper, we Propose a new scheme, protecting information about the location of a mobile user against attacks from inside users of the mobile communication, especially the network providers. There have already been some proposals about how to protect location information of user in mobile communication environments〔1-5〕. Among them, Kesdogan et al.〔2, 3〕 proposed a new method, using so-called temporary pseudonyms and also described protection method against a passive and an active attack of network providers. However, the description of protection method against the active attack between the two is not clear. Moreover, there is an additional load that it should append a reachability manager〔1, 6〕 to the proposed system. Therefore, we propose a new scheme improving the above method of Kesdogan et al. and analyze its security and effectiveness.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.322-332
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• 2017

Wireless Body Area Networks is an environment that provides an appropriate service remotely by collecting user's biometric information. With the growing importance of sensor, WBAN also attracts extensive attention. Since WBAN is representatively used in the medical field, it can be directly related to the patient's life. Hence security is very important in WBAN. Mutual authentication between the client and the application provider is essential. And efficiency is also important because a used device is limited to computation cost. In this reason, ID-based anonymous authentication scheme in WBAN has been intensively studied. We show that the recent research result of Wu et al. which is about the ID-based anonymous authentication scheme is vulnerable to impersonation attack. And we propose a new ID-based anonymous authentication scheme that is secure against the attacks discovered in the existing schemes. Compared to the existing schemes, the computation cost of our scheme is improved by 30.6% and 7.3%.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.9
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• pp.381-390
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• 2022

Influenced by a culture that prefers non-face-to-face activity during the COVID-19 pandemic, chatbot usage is accelerating. Chatbots have been used for various purposes, not only for customer service in businesses and social conversations for fun but also for mental health. Chatbots are a platform where users can easily talk about their depressed moods because anonymity is guaranteed. However, most relevant research has been on social media data, especially Twitter data, and few studies have analyzed the commercially used chatbots data. In this study, we identified the characteristics of depressive discourse in user-chatbot interaction data by analyzing the chats, including the word 'depress,' using the topic modeling algorithm and the text-mining technique. Moreover, we compared its characteristics with those of the depressive moods in the Twitter data. Finally, we draw several design guidelines and suggest avenues for future research based on the study findings.

• Convergence Security Journal
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• v.23 no.5
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• pp.45-55
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• 2023

With the widespread use of digital devices, anonymous communication technologies such as the dark web and deep web are becoming increasingly popular for criminal activity. Because these technologies leave little local data on the device, they are difficult to track using conventional crime investigation techniques. The United States and the United Kingdom have enacted laws and developed systems to address this issue, but South Korea has not yet taken any significant steps. This paper proposes a new blockchain-based crime investigation method that uses physical memory data analysis to track the behavior of anonymous network users. The proposed method minimizes infringement of basic rights by only collecting physical memory data from the device of the suspected user and storing the tracking information on a blockchain, which is tamper-proof and transparent. The paper evaluates the effectiveness of the proposed method using a simulation environment and finds that it can track the behavior of dark website users with a residual rate of 77.2%.