• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.1064-1079
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• 2019

Information security has become increasingly important with the rapid development of mobile devices and internet. An efficient encryption system is a key to this end. In this paper, we propose an image encryption method based on the cross diffusion of two chaotic maps. We use two chaotic sequences, namely the Logistic map and the Chebyshev map, for key generation which has larger security key space than single one. Moreover, we use these two sequences for further image encryption diffusion which decreases the correlation of neighboring pixels significantly. We conduct extensive experiments on several well-known images like Lena, Baboon, Koala, etc. Experimental results show that our algorithm has the characteristics of large key space, fast, robust to statistic attack, etc.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.195-199
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• 2008

We present an attack which forges a credential without the help of the credential issuer in the protocol designed by Nakazato, Wang and Yamamura at ASIAN 2007 The attack avoids using the credential issuer's private key by taking advantage of the property of bilinear pairing. Implication of this collusion attack by user and verifiers also discussed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.10 no.3
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• pp.37-48
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• 2000

서울Visual cryptography scheme is a simple method in which can be directly decoded the secret information in human visual system without performing any cryptographic computations. This scheme is a kind of secret sharing scheme in which if a secret of image type is scattered to n random images(slides) and any threshold (or more) of them are stacked together the original image will become visible. In this paper we consider (2, n) visual cryptography scheme and propose a new construction method in which the number of expanded pixels can be reduced by using the sample matrix. The proposed scheme can futhermore distribute the multiple secret image to each group according to the difference of relative contrast.

• International Journal of Computer Science & Network Security
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• v.21 no.5
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• pp.16-22
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• 2021

• Journal of Internet Computing and Services
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• v.23 no.2
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• pp.9-17
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• 2022

In this paper, we propose a secure smart home network model and a novel cryptographic protocol called the Smart Home Security Protocol (SHSP). Authentication, key distribution, and encryption functions are properly supported in order to make a smart home secure, and a residential gateway (RG) plays a central role in performing these functions. According to the characteristics of networks and attached devices, we classify smart homes into three different types of sub-networks and these networks are interconnected with one another by the RG. Depending on a sub-network, we use different types of secure schemes to reduce the burden of the process and the delay in devices while it provides proper security functions. The proposed secure smart home model is implemented and verified by using a variety of embedded system environments.

• International Journal of Computer Science & Network Security
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• v.22 no.11
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• pp.115-120
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• 2022

The main purpose of the study is to identify the key aspects of the use of innovative distance learning technologies in the training of biology students. Currently, there is a modernization, the evolution of the education system from a classical university to a virtual one, from lecture material teaching to computer educational programs, from a book library to a computer one, from multi-volume paper encyclopedias to modern search databases. During studies in higher education, distance learning ensures the delivery of information in an interactive mode through the use of information and communication technologies. The main disadvantage of distance learning is the emotional interaction of the teacher with students. It is necessary to increase the level of methodological developments for independent studies of students. The methodology includes a number of theoretical methods. Based on the results of the study, the main elements of the use of innovative distance learning technologies in the training of biology students were identified.

• International Journal of Computer Science & Network Security
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• v.23 no.3
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• pp.101-109
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• 2023

This paper discusses the use of sentiment analysis and text summarization techniques to extract valuable information from the large volume of user-generated content such as reviews, comments, and feedback on online platforms and social media. The paper highlights the effectiveness of sentiment analysis in identifying positive and negative reviews and the importance of summarizing such text to facilitate comprehension and convey essential findings to readers. The proposed work focuses on summarizing all positive and negative reviews to enhance product quality, and the performance of the generated summaries is measured using ROUGE scores. The results show promising outcomes for the developed methods in summarizing user-generated content.

• Annual Conference of KIPS
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• 2020.11a
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• pp.383-386
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• 2020

최근 국가기반시설을 대상으로 하는 사이버 공격이 증가하고 있다. 이에 따라 국내외에서는 시설의 침해영향도를 고려하여 자산을 분류하고 관리적/기술적/물리적 보안조치를 수행하도록 지침 및 정책을 제시하고 있다. 그러나 국내 지침은 자산 특성을 고려치 않아 운영 측면의 효율성을 저하하고 있다. 이에 본 논문은 기존 문서의 내용을 보완한 국가기반시설 정보보안 국가기반시설 정보보안 관리체계 프로그램을 제안한다.

• Annual Conference of KIPS
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• 2020.05a
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• pp.135-137
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• 2020

기업 내에서는 다양한 오픈소스를 활용하고 있다. 이런 환경에서 해당 오픈소스의 취약점 및 패치 현황을 실시간으로 제공하여 빠르게 대처하는 것이 중요하다. 먼저 기업 내에서 많이 사용하는 오픈소스를 조사한 후 Top 70 오픈소스를 선정하여 보안 취약점 및 패치 현황을 파악한다. 실제 크롤링을 통해 취약점을 수집한 후, 필요한 정보를 가공하여 웹 서비스로 시각화 하여 제공한다. 또한 취약점이 발생했을 때 기업에서는 실시간 메일 알람 서비스를 받아볼 수 있는 과정을 제시한다.

• Annual Conference of KIPS
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• 2022.05a
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• pp.260-263
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• 2022

현재의 교통정보시스템은 수집된 정보를 서버에서 가공하여 서비스하는 형태로 이루어져 있다. 이러한 형태는 네트워크 구성이 비교적 단순하고 유지관리 비용이 적게 든다는 장점이 있지만, 반면에 실시간성이 저하되고 보안이 제대로 보장되지 않을 수 있다는 문제가 있으며, 최근 많은 연구가 이루어지고 있는 VANET 환경에서의 교통정보시스템도 broadcast storm의 가능성을 안고 있다. 본 연구에서 제안하는 교통정보시스템은 자동차가 수집한 돌발 상황에 대한 데이터를 RSU(Road Side Unit)가 수신하고, 이후 메시지를 노드들에게 보낼 때 블록체인에 업로드함으로써 보안성과 broadcast storm 문제들을 해결할 수 있으며, raw data 를 IPFS 에 저장하여 시스템 고도화에 사용할 수 있어 참여자들이 교통 상황에 대해 신속하게 대응할 수 있도록 하는 장점을 갖는다.