• Journal of information and communication convergence engineering
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• 제1권4호
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• pp.183-188
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• 2003

The $4^{th}$ generation mobile communications, through several radio access networks such as WLAN, Bluetooth, UMTS, GPRS, CDMA 1X, and IMT-2000 in the same area offering different type of coverage, will support interactive multimedia services in additions to wider bandwidths, higher bit rates, and service portability. Regardless of various radio access networks, they will also support robust security mechanisms, as well as seamless mobility and common authentication. In this paper, we give an overview of WLAN security and examine its security problems. We also explain the enhanced security schemes, such as port-based authentication, EAP, and IEEE 802.1X. For secure wireless communications, several possible security solutions are offered and evaluated in various respects to improve WLAN security. This paper will make a contribution to provide more secure wireless communications to cellular operators embracing WLAN technology as a means to generate new revenues based on data services.

• 한국정보보호학회:학술대회논문집
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• 한국정보보호학회 2006년도 하계학술대회
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• pp.799-803
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• 2006

리눅스 메모리 덤프데이터 분석기술은 메모리에 저장되는 데이터를 찾는데 목적이 있고, 현재 수행중인 프로그램이나, 리눅스 커널의 오류 발생 원인을 찾는데 이용이 된다. 이 논문에서는 리눅스 메모리 덤프 방법과 메모리 덤프 데이터 분석 기술에 대하여 기존의 방법들을 조사한 결과를 설명한다. 메모리 덤프데이터 분석기술은 메모리에 저장되는 기본적인 데이터를 조사를 할 수 있고, 수행중인 프로그램을 분석하고, 이미 만들어진 시스템을 역으로 추적하여 애초의 문서나 설계기법 등의 자료를 얻어낼 수 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.7-8
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• 2006

F-HMIPv6 is protocol that supports fast handovers for Hierarchical Mobile IPv6. Unlike HMIPv6 (Hierarchical Mobile IPv6), it sends FBU(Fast Binding Update) by predicted Router's Information for a potential handover. But, The current version of this protocol doesn't ensure impeccably between mobile node and router. To make up for the weak points of the security, we propose the architecture for F-HMIPv6 protocol to structurally reinforce the security and improve weak security of among mobile node, MAP(Mobility Anchor Point), and routers for binding update when mobile node conducts handovers.

• 한국정보보호학회:학술대회논문집
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• 한국정보보호학회 2003년도 동계학술대회
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• pp.399-405
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• 2003

A new type of signature scheme, called NTRUSign, based on solving the approximately closest vector problem in an NTRU lattice was proposed in［7］,［8］. However no security proof against chosen messages attack has been made for this scheme. In this paper, we show that NTRUSign signature scheme contains the weakness of malleability. From this, one can derive new valid signatures from any previous message-signature pair which means that NTRUSign is not secure against strongly existential forgery.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4483-4501
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• 2015

In this paper, we investigate a security transmission scheme at the physical layer for cooperative wireless relay networks in the presence of a passive eavesdropper. While the security scheme has been previously investigated with perfect channel state information(CSI) in the presence of a passive eavesdropper, this paper focuses on researching the robust cooperative relay beamforming mechanism for wireless relay networks which makes use of artificial noise (AN) to confuse the eavesdropper and increase its uncertainty about the source message. The transmit power used for AN is maximized to degrade the signal-to-interference-plus-noise-ratio (SINR) level at the eavesdropper, while satisfying the individual power constraint of each relay node and worst-case SINR constraint at the desired receiver under a bounded spherical region for the norm of the CSI error vector from the relays to the destination. Cooperative beamforming weight vector in the security scheme can be obtained by using S-Procedure and rank relaxation techniques. The benefit of the proposed scheme is showed in simulation results.

• 융합보안논문지
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• 제16권6_2호
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• pp.23-32
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• 2016

급격한 정보통신기술의 발달은 경찰에게 새로운 도전이자 기회가 되고 있다. 이 연구는 국내외 치안분야의 ICT기술 활용사례를 검토하고, 그 시사점을 확인하는 것을 목적으로 한다. 이를 위해 정보통신기술 활용에 관한 경찰활동의 근거이론으로 정보주도 경찰활동(intelligence-led policing), 예측적 경찰활동(predictive policing), 증거기반 경찰활동(evidence-based policing)의 개념에 대해 소개하였다. 또, 빅데이터 기반 범죄분석과 예측기술 활용방안과 경찰의 정보통신체계 및 지휘통제기술의 고도화방안에 대해 논의하였다. 이 연구를 통해 확인한 시사점으로 (1) 기본데이터의 확보, (2) 활용가능한 통합D/B의 구축, (3) 정책결정자의 활용성 증대, (4) 유관기관 사이의 교류협력, (5) 전문가집단의 양성, (6) 통합 D/B구축의 법적 근거와 실무적 가이드라인 마련을 제안한다.

• Journal of information and communication convergence engineering
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• 제15권1호
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• pp.14-20
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• 2017

In this paper, we discuss physical layer security techniques in downlink networks, including eavesdroppers. The main objective of using physical layer security is delivering a perfectly secure message from a transmitter to an intended receiver in the presence of passive or active eavesdroppers who are trying to wiretap the information or disturb the network stability. In downlink networks, based on the random feature of channels to terminals, opportunistic user scheduling can be exploited as an additional tool for enhancing physical layer security. We introduce user scheduling strategies and discuss the corresponding performances according to different levels of channel state information (CSI) at the base station (BS). We show that the availability of CSI of eavesdroppers significantly affects not only the beamforming strategy but also the user scheduling. Eventually, we provide intuitive information on the effect of CSI on the secrecy performance by considering three scenarios: perfect, imperfect, and absence of eavesdropper's CSI at the BS.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권7호
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• pp.2246-2260
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• 2014

In this paper, a secure multilevel quadrature amplitude modulation (MQAM) scheme is proposed for the physical layer security (PLS) of the wireless communications. In the proposed scheme, each transmitted symbol's signal constellation (SC) is hopping with the control of two unique factors: amplitude distortion (AD) factor and phase hopping (PH) factor. With unknown the two factors, the eavesdropper cannot extract effective information from the received signal. We first introduce a security metric, referred to as secrecy gain, and drive a lower bound on the gain that the secrecy capacity can be improved. Then, we investigate the relationship among the secrecy gain, the signal to noise power ratios (SNRs) of the main and wiretap channels, and the secrecy capacity. Next, we analyze the security of the proposed scheme, and the results indicate that the secrecy capacity is improved by our scheme. Specifically, a positive secrecy capacity is always obtained, whether the quality of the main channel is better than that of the wiretap channel or not. Finally, the numerical results are provided to prove the analytical work, which further suggests the security of the proposed scheme.

• Journal of Communications and Networks
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• 제18권1호
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• pp.105-111
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• 2016

Trust models in the literature of MANETs commonly assume that packets have different security requirements. Before a node forwards a packet, if the recipient's trust level does not meet the packet's requirement level, then the recipient must perform certain security association procedures, such as re-authentication. We present in this paper an analysis of the epidemic broadcast delay in such context. The network, mobility and trust models presented in this paper are quite generic and allow us to obtain the delay component induced only by the security associations along a path. Numerical results obtained by simulations also confirm the accuracy of the analysis. In particular, we can observe from both simulation's and analysis results that, for large and sparsely connected networks, the delay caused by security associations is very small compared to the total delay of a packet. This also means that parameters like network density and nodes' velocity, rather than any trust model parameter, have more impact on the overall delay.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1904-1921
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• 2019

In this paper, we investigate the problem of secure communications in multiple-input-multiple-output interference networks from the perspective of physical layer security. Specifically, the legitimate transmitter-receiver pairs are divided into different categories of active and inactive. To enhance the security performances of active pairs, inactive pairs serve as cooperative jammers and broadcast artificial noises to interfere with the eavesdropper. Besides, active pairs improve their own security by using joint transceivers. The encoding of active pairs and inactive pairs are designed by maximizing the difference of mean-squared errors between active pairs and the eavesdropper. In detail, the transmit precoder matrices of active pairs and inactive pairs are solved according to game theory and linear programming respectively. Experimental results show that the proposed algorithm has fast convergence speed, and the security performances in different scenarios are effectively improved.