• Journal of Communications and Networks
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• 제12권5호
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• pp.411-432
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• 2010

We consider three different secure broadcasting scenarios: i) Broadcast channels with common and confidential messages (BCC), ii) multi-receiver wiretap channels with public and confidential messages, and iii) compound wiretap channels. The BCC is a broadcast channel with two users, where in addition to the common message sent to both users, a private message, which needs to be kept hidden as much as possible from the other user, is sent to each user. In this model, each user treats the other user as an eavesdropper. The multi-receiver wiretap channel is a broadcast channel with two legitimate users and an external eavesdropper, where the transmitter sends a pair of public and confidential messages to each legitimate user. Although there is no secrecy concern about the public messages, the confidential messages need to be kept perfectly secret from the eavesdropper. The compound wiretap channel is a compound broadcast channel with a group of legitimate users and a group of eavesdroppers. In this model, the transmitter sends a common confidential message to the legitimate users, and this confidential message needs to be kept perfectly secret from all eavesdroppers. In this paper, we provide a survey of the existing information-theoretic results for these three forms of secure broadcasting problems, with a closer look at the Gaussian multiple-input multiple-output (MIMO) channel models. We also present the existing results for the more general discrete memoryless channel models, as they are often the first step in obtaining the capacity results for the corresponding Gaussian MIMO channel models.

• Kyungpook Mathematical Journal
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• 제53권1호
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• pp.25-35
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• 2013

In this paper, we introduce and study the concept of "strongly $t$-linked extensions", which is a stronger version of $t$-linked extensions of integral domains. We show that for an extension of Pr$\ddot{u}$fer $v$-multiplication domains, this concept is equivalent to that of "$w$-faithfully flat".

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권5호
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• pp.2427-2445
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• 2016

In contrast to traditional "store-and-forward" routing mechanisms, network coding offers an elegant solution for achieving maximum network throughput. The core idea is that intermediate network nodes linearly combine received data packets so that the destination nodes can decode original files from some authenticated packets. Although network coding has many advantages, especially in wireless sensor network and peer-to-peer network, the encoding mechanism of intermediate nodes also results in some additional security issues. For a powerful adversary who can control arbitrary number of malicious network nodes and can eavesdrop on the entire network, cryptographic signature schemes provide undeniable authentication mechanisms for network nodes. However, with the development of quantum technologies, some existing network coding signature schemes based on some traditional number-theoretic primitives vulnerable to quantum cryptanalysis. In this paper we first present an efficient network coding signature scheme in the standard model using lattice theory, which can be viewed as the most promising tool for designing post-quantum cryptographic protocols. In the security proof, we propose a new method for generating a random lattice and the corresponding trapdoor, which may be used in other cryptographic protocols. Our scheme has many advantages, such as supporting multi-source networks, low computational complexity and low communication overhead.

• ETRI Journal
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• 제37권3호
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• pp.584-594
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• 2015

To date, many different kinds of logic styles for hardware countermeasures have been developed; for example, SABL, TDPL, and DyCML. Current mode-based logic styles are useful as they consume less power compared to voltage mode-based logic styles such as SABL and TDPL. Although we developed TPDyCML in 2012 and presented it at the WISA 2012 conference, we have further optimized it in this paper using a binary decision diagram algorithm and confirmed its properties through a practical implementation of the AES S-box. In this paper, we will explain the outcome of HSPICE simulations, which included correlation power attacks, on AES S-boxes configured using a compact NMOS tree constructed from either SABL, CMOS, TDPL, DyCML, or TPDyCML. In addition, to compare the performance of each logic style in greater detail, we will carry out a mutual information analysis (MIA). Our results confirm that our logic style has good properties as a hardware countermeasure and 15% less information leakage than those secure logic styles used in our MIA.

• 지능정보연구
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• 제26권3호
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• pp.37-50
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• 2020

사물 인터넷, 빅데이터, 클라우드, 인공지능 등 다양한 정보통신기술이 발전하면서, 정보보호의 대상이 증가하고있다. 정보통신기술의 발전에 비례해서 정보보호의 필요성이 확대되고 있지만, 정보보호 투자에 대한 관심은 저조한 상황이다. 일반적으로 정보보호와 관련된 투자는 효과를 측정하기 어렵기 때문에 적절한 투자가 이루어지지 않고 있으며, 대부분의 조직은 투자 규모를 줄이고 있다. 또한 정보보호 대책의 종류와 특성이 다양하기 때문에 객관적인 비교와 평가가 힘들고, 객관적인 의사결정 방법이 부족한 실정이다. 하지만 조직의 발전을 위해서는 정보보호와 관련된 정책과 의사결정이 필수적이며 적정 수준의 투자와 이에 대한 투자 효과를 측정 할 필요가 있다. 이에 본 연구에서는 게임 이론을 이용하여 정보보호 대책 투자 포트폴리오를 구성하는 방법을 제안하고 선형계획법을 이용하여 최적 방어 확률을 도출한다. 2인 게임 모형을 이용하여 정보보호 담당자와 공격자를 게임의 경기자로 구성한 뒤, 정보보호 대책을 정보보호 담당자의 전략으로, 정보보호 위협을 공격자의 전략으로 각각 설정한다. 게임 모형은 경기자의 보수의 합이 0인 제로섬 게임을 가정하고, 여러개의 전략 사이에서 일정한 확률 분포에 따라 전략을 선택하는 혼합 전략 게임의 해를 도출한다. 여러 종류의 위협이 존재하는 현실에서는 한 개의 정보보호 대책만으로 일정 수준 이상의 방어가 힘들기 때문에, 다수의 정보보호 대책을 고려해야한다. 따라서 다수의 정보보호 위협에 따른 정보보호 대책이 배치된 환경에서 정보보호 대책의 방어 비율을 이용하여 정보보호 대책 투자 포트폴리오를 산출한다. 또한 최적화된 포트폴리오를 이용하여 방어 확률을 최대화하는 게임 값을 도출한다. 마지막으로 정보보호 대책의 실제 성능 데이터를 이용하여 수치 예제를 구성하고, 제안한 게임 모델을 적용하고 평가한다. 본 연구에서 제시한 최적화 모델을 이용하면 조직의 정보보호 담당자는 정보보호 대책의 방어 비율을 고려하여 정보보호 대책의 투자 가중치를 구할 수 있고, 효과적인 투자 포트폴리오를 구성하여 최적의 방어 확률을 도출 할 수 있을 것이다.

• 한국경영정보학회:학술대회논문집
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• 한국경영정보학회 2007년도 International Conference
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• pp.141-146
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• 2007

The importance of the net-based customer service in delivering supplementary after-sale services associated with product has been well documented. The strategic advantages of a well-implemented the net-based customer service are enhanced customer loyalty and higher lock-in of customers, and the resulting reduction in competition and the consequent increase in profits. However, not all customers utilize such the net-based customer service. This is partly due to the e-commerce divide, and partly due to privacy and security concerns of the customer for sharing personal information with firms. The limited level of customer adoption of the net-based customer service affects the firm profits and the customers' welfare. We use a game-theoretic model in which we model the net-based customer service system as a mechanism to enhance customers' loyalty. We find that an increase in adoption of the net-based customer service by the customer base is not always desirable for firms. and that customers who utilize such services are better off only when the overall adoption is limited.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 1997년도 춘계학술대회 발표논문집
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• pp.163-181
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• 1997

This dissertation provides a theroetic study on the network security in general , the firewall in particular . In fact, the firewall has been recognized as a very promising option to obtain the security in the real world network environment . The dissertation provides a thorough theoretic investigation on the various problems raised in the computer network, and also explores a methodology of the security against IP spoofing. Moreover, it investigates a systematic procedure to make analysis plans of the firewall configuration. Based on the above investigation and analysis , this dissertation provides two approaches to network security, which address a number of issues both at the network and at application level. At the network level. a new methdo is proposed which uses packet filtering based on the analysis of the counter plot about the screen router. On the other hand at the application level, a novel method is exlored which employs security software , Firewall-1, on Bastion host. To demonstrate the feasibility and the effectiveness of the proposed methodologes, a prototype implementation is made. The experiment result shows that the screen router employing the proposesed anti-IP spoofing method at the network level is effective enough for the system to remain secure without being invaded by any illegarl packets entering from external hackers. Meanwhile , at the application level. the proposed software approach employing Firewall -1 is proved to be robust enough to provent hackings from the outer point to point protocol connection. Theoretically, it is not possible to provide complete secuirty to the network system, because the network security involove a number of issues raised from low level network equipments form high level network protocol. The result in this dissertation provides a very promising solution to network security due to its high efficiency of the implementation and superb protectiveness from a variety of hacking.

• 대한수학회지
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• 제48권1호
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• pp.191-205
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• 2011

It is well known that for a Krull domain R, the divisor class group of R is a torsion group if and only if every subintersection of R is a ring of quotients. Thus a natural question is that under what conditions, for a non-Krull domain R, every (t-)subintersection (resp., t-linked overring) of R is a ring of quotients or every (t-)subintersection (resp., t-linked overring) of R is at. To address this question, we introduce the notions of *-compact packedness and *-coprime packedness of (an ideal of) an integral domain R for a star operation * of finite character, mainly t or w. We also investigate the t-theoretic analogues of related results in the literature.

• 대한수학회보
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• 제49권3호
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• pp.601-608
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• 2012

The following statements for an infra-Krull domain $R$ are shown to be equivalent: (1) $R$ is a Krull domain; (2) for any essentially finite $w$-module $M$ over $R$, the torsion submodule $t(M)$ of $M$ is a direct summand of $M$; (3) for any essentially finite $w$-module $M$ over $R$, $t(M){\cap}pM=pt(M)$, for all maximal $w$-ideal $p$ of $R$; (4) $R$ satisfies the $w$-radical formula; (5) the $R$-module $R{\oplus}R$ satisfies the $w$-radical formula.

• 한국산학기술학회논문지
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• 제14권3호
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• pp.1439-1444
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• 2013

최근 들어, 네트워크의 급속한 발전으로 온라인 뱅킹과 주식 거래 같은 응용프로그램들의 사용이 증가함에 따라 데이터에 대한 보안은 점점 더 중요해 지고 있다. 따라서, 데이터 보호를 위해 인터넷과 같은 개방형 네트워크에서 공개키 또는 대칭키 암호 알고리즘이 널리 사용되고 있다. 일반적으로 공개키 암호시스템은 인수분해와 이산대수의 문제를 기반으로 하고 있어, 대칭키 암호시스템에 비해 처리속도가 상대적으로 느리다. 공개키 암호시스템 중 타원곡선 암호는 RSA에 비해 보다 작은 사이즈의 키를 사용하여도 동일한 보안성을 제공하는 장점이 있어 처리 속도가 빠르다. 본 논문에서는 실수체를 기반으로 하는 타원곡선 암호의 효율적인 키 생성 방법을 제안한다.