• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권8호
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• pp.3550-3566
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• 2020

As a widely used way to exfiltrate information, wireless covert channel (WCC) brings a serious threat to communication security, which enables the wireless communication process to bypass the authorized access control mechanism to disclose information. Unlike the covert channel on the network layer, wireless covert channels on the physical layer (WCC-P) is a new covert communication mode to implement and improve covert wireless communication. Existing WCC-P scheme modulates the secret message bits into the Gaussian noise, which is also called covert digital communication system based on the joint normal distribution (CJND). Finding the existence of this type of covert channel remains a challenging work due to its high undetectability. In this paper, we exploit the square autocorrelation coefficient (SAC) characteristic of the CJND signal to distinguish the covert communication from legitimate communication. We study the sharp increase of the SAC value when the offset is equal to the symbol length, which is caused by embedding secret information. Then, the SAC value of the measured sample is compared with the threshold value to determine whether the measured sample is CJND sample. When the signal-to-noise ratio reaches 20db, the detection accuracy can reach more than 90%.

• 한국인터넷방송통신학회논문지
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• 제20권2호
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• pp.29-37
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• 2020

기존에 사용되던 방화벽들은 기본적으로 정책을 수동적으로 입력해 주는 방식으로 되어 있어 공격이 오는 즉시 대응하기 쉽지 않다. 왜냐하면 전문 보안 관리자가 이를 분석하고 해당 공격에 대한 방어 정책을 입력해 주어야하기 때문이다. 또한, 기존 방화벽 정책은 공격을 막기 위해 정상 접속까지 차단하는 경우가 많다. 패킷 자체는 정상적이지만 유입량이 많아 서비스 거부를 발생시키는 공격이 많기 때문이다. 본 논문에서는 방어 정책을 입력하는 부분을 인공지능으로 대체하여 정책을 자동으로 생성하고, 정상 접속 학습을 통해 생성된 화이트리스트 정책으로 정상 접속은 가능하면서 Flooding, Spoofing, Scanning과 같은 공격만을 차단하는 방법을 제안한다.

• 한국멀티미디어학회논문지
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• 제9권3호
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• pp.342-352
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• 2006

오늘날 컴퓨팅 환경은 유비쿼터스로 변화하고 있다. 유비쿼터스 컴퓨팅 환경은 사용자들이 언제 어디서나 컴퓨팅 자원에 접근할 수 있는 스마트 공간(Smart space)으로 실현될 것이다. 그러나 스마트 공간내의 자원들에게 사전에 신뢰받지 못한 상태의 사용자들이 안전하게 자원들에 접근하기 위해서는 사용자들과 자원들 사이에 안전한 신뢰 관계를 형성하기 위한 기법이 요구된다. 본 논문에서는 유비쿼터스 컴퓨팅 환경에서의 신뢰 관계 형성을 위하여 기존에 제안된 분산된 신뢰(Distributed trust) 기법의 "악의적 권한 위임"과 "위임권한 취소"에 대한 보안 문제점을 지적하고, 보안성이 개선된 새로운 참여 제어 시스템을 제안한 후 이를 구현한다.

• 디지털산업정보학회논문지
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• 제6권4호
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• pp.117-130
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• 2010

Paper is on defense for so-called internet crisis, the attack of DDoS (Distributed Denial of Service) which was targeted to the central government ministries, financial sector, and portal sites of chief counties including Korea on June 7th, 2009 as its start. By conducting attack with various DDoS attacking methods in the lab environment and dividing networks targeted by the attack by layers, this paper records and analyzes the chief information for attack, destination information of packets, defense policy setting, and the flow of packet attack with the subjects of the networks separated. This study suggests CFC system using multiple firewalls applying defense policy corresponding to the target layer for ultimate attack and tests it according to the result of analyzing the attack packet information and its amount, log analysis, access recording port, and MAC and IT information, etc. by layers. This article is meaningful in that it analyzes the attack by layers, establishes firewall policy for protecting each layer, and secures accurate mechanism for detect and defense.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권10호
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• pp.4176-4197
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• 2020

Botnet is a type of dangerous malware. Botnet attack with a collection of bots attacking a similar target and activity pattern is called bot group activities. The detection of bot group activities using intrusion detection models can only detect single bot activities but cannot detect bots' behavioral relation on bot group attack. Detection of bot group activities could help network administrators isolate an activity or access a bot group attacks and determine the relations between bots that can measure the correlation. This paper proposed a new model to measure the similarity between bot activities using the intersections-probability concept to define bot group activities called as B-Corr Model. The B-Corr model consisted of several stages, such as extraction feature from bot activity flows, measurement of intersections between bots, and similarity value production. B-Corr model categorizes similar bots with a similar target to specify bot group activities. To achieve a more comprehensive view, the B-Corr model visualizes the similarity values between bots in the form of a similar bot graph. Furthermore, extensive experiments have been conducted using real botnet datasets with high detection accuracy in various scenarios.

• 보건행정학회지
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• 제16권4호
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• pp.86-111
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• 2006

Either ways of understanding health care as a commodity or public work are at opposite ends of health care spectrum. These two rival conceptions reflected by viewpoint(ideology) would lead to different directions in policy-making for health care reform. The purpose of this study is to access the value differences of experts' policy views about health care issues by analyzing the extent of consensus among experts in the field of health care. Using primary data obtained through a mail survey of 558 experts in the field of health care, we analyzed the differences of experts' opinions about characteristics of health care market, policy issues and values Gdeology). The study represents from 50-50 split analysis, entropy index, and factor analysis that the wide spread disagreements over health policy, which is a major barriers to effective policy-making, could be caused by the ideological perception differences among experts. This implies that, if values play an important role in policy-making, we should identify the differences in value and seek ways to balance among the diverse values such as efficiency, equity, freedom, and security. For this, the policy issues debated on differences in values should be reconciled for narrowing gaps of experts' perceptions through various ways.

• 한국통신학회논문지
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• 제28권7C호
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• pp.743-750
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• 2003

컴퓨터 기술의 확산과 더불어 분산 컴퓨팅 환경에서 이동에이전트 코드의 이동성은 유연성이 있어 인터넷상에서 분배된 애플리케이션들을 설치하는데 사용되고 있다. 동시에, 이동에이전트의 이동코드를 전송하고 멀리 떨어진 곳의 호스트로부터 수신할 수 있는 능력을 가지고 있어서 에이전트가 실행되는 호스트 시스템의 실행 환경은 에이전트의 코드와 이를 실행할 수 있는 실행 환경에 접근을 해야 함으로 악의적인 행위들로부터 에이전트의 위조, 변조, 잘못된 실행을 방지하기가 매우 어렵다. 따라서 본 논문은 암호화된 에이전트의 코드와 상태 추적을 통하여 여러 악의적인 행위로부터 에이전트를 보호할 수 있도록 하는 메카니즘을 제안한다 제안한 메카니즘을 통해 이동에이전트가 보호되는 과정을 통해서 안전성을 증명하였다.

• Journal of Communications and Networks
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• 제17권5호
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• pp.506-516
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• 2015

Wireless sensor networks (WSNs) are generally comprised of densely deployed sensor nodes, which results in highly redundant sensor data transmissions and energy waste. Since the sensor nodes depend on batteries for energy, previous studies have focused on designing energy-efficient medium access control (MAC) protocols to extend the network lifetime. However, the energy-efficient protocols induce an extra end-to-end delay, and therefore recent increase in focus on WSNs has led to timely and reliable communication protocols for mission-critical applications. In this paper, we propose an energy efficient and delay guaranteeing node scheduling scheme inspired by biological systems, which have gained considerable attention as a computing and problem solving technique.With the identification of analogies between cellular signaling systems and WSN systems, we formulate a new mathematical model that considers the networking challenges of WSNs. The proposed bio-inspired algorithm determines the state of the sensor node, as required by each application and as determined by the local environmental conditions and the states of the adjacent nodes. A control analysis shows that the proposed bio-inspired scheme guarantees the system stability by controlling the parameters of each node. Simulation results also indicate that the proposed scheme provides significant energy savings, as well as reliable delay guarantees by controlling the states of the sensor nodes.

• 한국중재학회지:중재연구
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• 제13권2호
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• pp.425-457
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• 2004

This study is to approach e-Trade issues and how to settle the dispute for e-Trade according to on-line Alternative Dispute Resolution (ADR) process. Most on-line systems operate on a limited access basis. The increasing use of the internet to do business brings to light at least important concerns to persons who engage in commerce on-line, or e-Trade. There is some concern about the limits of current internet technology to guarantee the security of e-Trade. The new technology has transformed society and is defining new years of doing business. This revolution in technology has even changed the nature of many of the goods and services that are the subjects of e-Trade. There is also concern about the limits of the legal framework to guarantee the enforcement of e-Trade. A significant issue is how the law should be adapted to reflect business practices regarding such cyberspace agreements as Web site click-on agreements, e-data interchange, and on-line sales. The principal benefits of on-line ADR should typically be faster and less expensive than traditional conciliation arbitration. The on-line ADR system has the several significances, decreasing inappropriate cost as time and burden of ADR, providing an approachable measure of relief and more efficient tool for the settle of dispute. Therefore, on-line ADR could be used as an adjunct resolution process in large class actions where each single claim is small, but varies somewhat, thus requiring some individual fact determination.

• 정보처리학회논문지C
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• 제13C권3호
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• pp.375-382
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• 2006

다양한 종류의 임베디드 시스템이 폭넓게 사용됨에 따라, 임베디드 정보 가전에 접근하고 제어할 수 있는 홈 네트워크 미들웨어에 관한 연구가 활발히 진행 중이다. 그러나 제한된 저장 공간과 낮은 컴퓨팅 능력은 홈 네트워크 기술을 임베디드 시스템에 적용했을 때 심각한 문제를 발생시킨다. 본 논문에서는 홈 네트워크 미들웨어의 실제 성능을 강화하기 위해 이동성 관리를 지원하는 경량 미들웨어를 제시한다. 이동성 관리는 애니캐스트 기술을 적용하여 구현하였으며, IP 기반의 홈 네트워크는 서비스(디바이스)가 노출되어 있기 때문에 사용자의 신원을 확인하는 인증과 정근에 관한 보안 기술을 제안한다.