• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2002년도 가을 학술발표논문집 Vol.29 No.2 (3)
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• pp.139-141
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• 2002

최근 보안에 관한 관심이 높아지면서 IPSec을 이용한 VPN system이 널리 이용되고 있다. IPSec에서 암호화에 사용되는 키를 생성하는 IKE는 IPSec의 핵심 프로토콜이지만다소 복잡하고 메시지 교환도 많아 패킷의 손실이 큰 무선망에는 적합하지 않다. 무선망에서 좀 더 효율적으로 동작하기 위한 인터넷 키 교환 방법 및 공개키 기반구조를 제시하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권6호
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• pp.1418-1432
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• 2013

This paper studies the problem of secure information exchange between two sources via multiple relays in the presence of an eavesdropper. To this end, we propose a relay beamforming scheme, i.e., relay beamforming with artificial noise (RBwA), where the relay beamforming vector and the artificial noise vector are jointly designed to maintain the received signal-to-interference-ratio (SINR) at the two sources over a predefined Quality of Service (QoS) threshold while limiting the received SINR at the eavesdropper under a predefined secure threshold. For comparison, the relay beamforming without artificial noise (RBoA) is also considered. We formulate two optimization problems for the two schemes, where our goal is to seek the optimal beamforming vector to minimize the total power consumed by relay nodes such that the secrecy of the information exchange between the two sources can be protected. Since both optimization problems are nonconvex, we solve them by semidefinite program (SDP) relaxation theory. Simulation results show that, via beamforming design, physical layer secrecy of two-way relay networks can be greatly improved and our proposed RBwA outperforms the RBoA in terms of both low power consumption and low infeasibility rate.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(3)
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• pp.51-54
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• 2002

P2P implies direct exchange between peers. If you have something I want, 1 go directly to you and obtain il. There is one of the most advantages of formation of community in P2P. For a specified purpose through P2P, the Peers who make temporary a group delivery a request efficient and safe. And the resources can be jointed common, cooperation and communication. When P2P is developed more, we can expect more formation of online community and development. But to be a safe of personal ID and password in internet, it should be possible to make a key-exchange. In the paper, it suggest P2P security system suitable to personal security that Kerberos be transformed. The user who make community in P2P, have Kerberos Server, and using Physical Address of Ethernet card in personal computer, authenticate users.

• 정보보호학회논문지
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• 제31권6호
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• pp.1247-1260
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• 2021

최근, 무선 센서 네트워크에서 더욱 효율적인 노드의 에너지 관리를 위해 센서 데이터를 대신 수집해주는 모바일 싱크 노드에 관한 연구가 있었다. 대표적인 모바일 싱크 노드로는 UAV (Unmanned Aerial vehicle)가 사용되며, 학계에서는 최적의 UAV 경로를 계산하는 알고리즘을 제시하는 위주로 IoD (Internet of Drones) 환경의 급격한 발전을 만들어냈다. 동시에, 보안 관점에서 다수의 노드와 세션키를 효율적으로 만들어야 하는 IoD의 특성에 맞춰 상호 인증 및 안전한 키 교환을 목표로 하는 기법들이 몇몇 제시되었다. 하지만, 모바일 싱크 노드 환경에서의 안전한 통신을 제안한 대부분 논문은 종단 간 데이터 프라이버시가 지켜지지 않았다. 따라서 본 논문에서는 모바일 싱크 노드와 센서 노드 간 인증부터 모바일 싱크 노드가 센서 데이터를 기지국까지 안전하게 중계하는 통합적 보안 모델을 처음으로 제안한다. 또한, 제안한 프로토콜의 안전성을 비공식적으로 입증하고 알려진 다양한 공격으로부터 안전함을 보인다. 마지막으로 기존에 제시된 IoD 환경에서 안전한 키 교환을 주제로 한 기법들과 통신 오버헤드를 비교해 본 논문에서 제시한 기법이 우수하다는 것을 보여준다.

• 전자공학회논문지CI
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• 제48권3호
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• pp.18-26
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• 2011

최근 급성장하고 있는 소셜 네트워크 서비스는 인적 네트워크를 반영한 온라인 서비스로서 선거 유세, 기업 홍보 마케팅, 교육적 정보 공유, 의학적 지식 및 의견 교환 등 다양한 목적으로 사용되고 있다. 이 서비스는 공동의 관심사를 가진 사람들이 모여 자유롭게 정보와 의견을 교환하면서 친분관계를 형성하도록 하고, 자신의 프로파일과 친분관계에 있는 사람들을 공개함으로써 다른 사람의 인맥을 활용하여 자신의 관계를 확장시켜 나갈 수 있도록 한다. 그러나 정보의 개방과 공유를 기반으로 하는 소셜 네트워크 서비스는 프라이버시 침해나 피싱과 같은 많은 보안상의 문제를 야기 시킨다. 본 논문에서는 키링을 이용하여 소셜 네트워크에서 소규모 그룹의 통신을 보호하기 위한 키 관리 기법 및 프로토콜을 제시하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권7호
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• pp.2512-2529
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• 2015

Wireless mesh networks (WMNs) provide an efficient and flexible method to the field of wireless networking, but also bring many security issues. A mesh point may lose all of its available links during its movement. Thus, the mesh point needs to handover to a new mesh point in order to obtain access to the network again. For multi-domain WMNs, we proposed a new ID-based signcryption scheme and accordingly present a novel ID-based handover protocol for mesh points. The mutual authentication and key establishment of two mesh points which belong to different trust domains can be achieved by using a single one-round message exchange during the authentication phase. The authentication server is not involved in our handover authentication protocol so that mutual authentication can be completed directly by the mesh points. Meanwhile, the data transmitted between the two mesh points can be carried by the authentication messages. Moreover, there are no restrictions on the PKG system parameters in our proposed multi-domain ID-based signcryption scheme so our handover scheme can be easily applied to real WMNs circumstances. Security of the signcryption scheme is proved in the random oracle model. It shows that our protocol satisfies the basic security requirements and is resistant to existing attacks based on the security of the signcryption. The analysis of the performance demonstrates that the protocol is efficient and suitable for the multi-domain WMNs environment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권2호
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• pp.389-405
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• 2014

Outdated Channel State Information (CSI) was proved to have negative effect on performance in two-way relay networks. The diversity order of widely used opportunistic relay selection (ORS) was degraded to unity in networks with outdated CSI. This paper proposed a multiple relay selection scheme for amplify-and-forward (AF) based two-way relay networks (TWRN) with outdated CSI. In this scheme, two sources exchange information through more than one relays. We firstly select N best relays out of all candidate relays with respect to signal-noise ratio (SNR). Then, the ratios of the SNRs on the rest of the candidate relays to that of the Nth highest SNR are tested against a normalized threshold ${\mu}{\in}[0,1]$, and only those relays passing this test are selected in addition to the N best relays. Expressions of outage probability, average bit error rate (BER) and ergodic channel capacity were obtained in closed-form for the proposed scheme. Numerical results and Simulations verified our theoretical analyses, and showed that the proposed scheme had significant gains comparing with conventional ORS.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권8호
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• pp.1955-1971
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• 2013

This paper studies relay selection and power allocation for amplify-and-forward (AF) based two-way relay networks (TWRN) with asymmetric traffic requirements (ATR). A joint relay selection and power allocation algorithm is proposed to decrease the outage probability of TWRN with ATR. In this algorithm, two sources exchange information with the help of the relay during two time slots. We first calculate the optimal power allocation parameters based on instantaneous channel state information (CSI), and then derive a tight lower bound of outage probability. Furthermore, we propose a simplified relay selection criterion, which can be easily calculated as harmonic mean of instantaneous channel gains, according to the outage probability expressions. Simulation results verified the theoretical analyses we presented. It is shown that the outage probability of our algorithm improves 3-4dB comparing with that of other existing algorithms, and the lower bound is tight comparing with actual value for the entire signal-to-noise ratio (SNR) region.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권8호
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• pp.2675-2690
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• 2014

We study the problem of optimal opportunistic spectrum access with unknown and heterogeneous channel dynamics in cognitive radio networks. There is neither statistic information about the licensed channels nor information exchange among secondary users in the respective systems. We formulate the problem of maximizing network throughput. To achieve the desired optimization, we propose a win-shift lose-stay algorithm based only on rewards. The key point of the algorithm is to make secondary users tend to shift to another channel after receiving rewards from the current channel. The optimality and the convergence of the proposed algorithm are proved. The simulation results show that for both heterogeneous and homogenous systems the proposed win-shift lose-stay algorithm has better performance in terms of throughput and fairness than an existing algorithm.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2003년도 추계학술발표논문집 (하)
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• pp.1977-1980
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• 2003

현재 가상사설망(VPN)의 보안 프로토콜로 사용되고 있는 IPSec(IP security)은 보안에 취약한 인터넷망을 타고 전달되는 IP 패킷을 대상으로 패킷의 기밀성과 무결성 및 송신자 인증이라는 보안 서비스를 제공해주는 강력한 인터넷 보안 메커니즘의 하나이다. 그러나 IPSec의 키 분배 및 관리를 위해 사용되고 있는 IKE(Internet Key Exchange)는 그 복잡성으로 인해 정확한 암호학적 분석이 어렵고 이를 응용한 어플리케이션 사이의 상호 호환을 어렵게 하고 있다. 따라서 본 논문에서는 이러한 문제를 해결하기 위해 기존의 IKE를 변형한 새로운 키 알고리즘을 제시한다.