• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.4226-4241
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• 2014

Cloud storage provides an easy, cost-effective and reliable way of data management for users without the burden of local data storage and maintenance. Whereas, this new paradigm poses many challenges on integrity and privacy of users' data, since users losing grip on their data after outsourcing the data to the cloud server. In order to address these problems, recently, Worku et al. have proposed an efficient privacy-preserving public auditing scheme for cloud storage. However, in this paper, we point out the security flaw existing in the scheme. An adversary, who is on-line and active, is capable of modifying the outsourced data arbitrarily and avoiding the detection by exploiting the security flaw. To fix this security flaw, we further propose a secure and efficient privacy-preserving public auditing scheme, which makes up the security flaw of Worku et al.'s scheme while retaining all the features. Finally, we give a formal security proof and the performance analysis, they show the proposed scheme has much more advantages over the Worku et al.'s scheme.

• 전기학회논문지
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• 제66권6호
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• pp.916-922
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• 2017

Security systems for inland cargo truck transportation are mostly limited to route tracking for safe and efficient transportation. With this route tracking system, the status of cargo trucks can be monitored easily within inland boundaries. In case of oil transportation by land, however, security systems ensuring transportation of a designated quantity of products have been subject to extensive research since thefts and substitution by a similar product in the transportation process have emerged as a social problem. Security devices installed in an oil tank truck must meet the explosion-proof performance standards and be applicable to varying types of trucks. Accordingly, a wireless electronic seal with RF communication functions is considered to be the most appropriate method, but e-seals on moving vehicles require such levels of performance and reliability that can overcome certain challenges including changing radio waves and topographical impediments. Considering these characteristics of oil tank trucks, this study proposes an stabilization method to enhance the RF communication performance of e-seals, based on radio simulation and experiment findings.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권11호
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• pp.5639-5653
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• 2016

Security models for key exchange protocols have been researched for years, however, lots of them only focus on what secret can be compromised but they do not differentiate the timing of secrets compromise, such as the extended Canetti-Krawczyk (eCK) model. In this paper, we propose a new security model for key exchange protocols which can not only consider what keys can be compromised as well as when they are compromised. The proposed security model is important to the security proof of the key exchange protocols with forward secrecy (either weak forward secrecy (wFS) or strong forward secrecy (sFS)). In addition, a new kind of key compromise impersonation (KCI) attacks which is called strong key compromise impersonation (sKCI) attack is proposed. Finally, we provide a new one-round key exchange protocol called mOT+ based on mOT protocol. The security of the mOT+ is given in the new model. It can provide the properties of sKCI-resilience and sFS and it is secure even if the ephemeral key reveal query is considered.

• 융합보안논문지
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• 제8권1호
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• pp.91-100
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• 2008

The previous works in sensor networks security have focused on the aspect of confidentiality, authentication and integrity based on cryptographic primitives. There has been no prior work to assess the survivability in systematic way. Accordingly, this paper presents a survivability model of wireless sensor networks using software rejuvenation for dual adaptive cluster head. The survivability model has state transition to reflect status of real wireless sensor networks. In this paper, we only focus on a survivability model which is capable of describing cluster head compromise in the networks and able to switch over the redundant cluster head in order to increase the survivability of that cluster. Second, this paper presents how to enhance the survivability of sensor networks using software rejuvenation methodology for dual cluster head in wireless sensor network. We model and analyze each cluster as a stochastic process based on Semi Markov Process (SMP) and Discrete Time Markov Chain (DTMC). The proof of example scenarios and numerical analysis shows the feasibility of our approach.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권12호
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• pp.2392-2402
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• 2011

In order to protect some important information communicated through an insecure network, a common hidden key must be used. One can produce the common hidden key using key agreement protocols; and this helps to have high security in modern data networks. Today, the designers of public key cryptography protocols try to set the public identity of a system's users (like their email addresses) as their public key. This not only makes a cryptographic protocol more efficient but also decreases its cost. These protocols are called "identity-based". In this article, an identity-based multiple key agreement scheme will be presented; this scheme uses the challenge-response method to do the verification. While the number of random values produced in our scheme is the same as other schemes, the number of keys generated in this scheme is much more than what many other key agreement schemes produce,. Therefore, we will have less computational complexities campered with other schems. In this paper, we consider the security of our scheme and consequently, we will show that it satisfies many security conditions such as strong security.

• 충청수학회지
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• 제15권2호
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• pp.47-56
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• 2003

This note is concerned with some properties of fixed points and periodic points. First, we have constructed a generalized continuous function to give a proof for the fact that, as the reverse of the Sharkovsky theorem[16], for a given positive integer n, there exists a continuous function with a period-n point but no period-m points wherem is a predecessor of n in the Sharkovsky ordering. Also we show that the composition of two transcendental meromorphic functions, one of which has at least three poles, has infinitely many fixed points.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권12호
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• pp.6092-6115
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• 2017

This paper demonstrates a case for an end-to-end pure Application Security Layer for reliable and confidential communications within an Internet of Things (IoT) constrained environment. To provide a secure key exchange and to setup a secure data connection, Transport Layer Security (TLS) is used, which provides native protection against replay attacks. TLS along with digital signature can be used to achieve non-repudiation within app-to-app communications. This paper studies the use of TLS over the JavaScript Object Notation (JSON) via a The Constrained Application Protocol (CoAP) RESTful service to verify the hypothesis that in this way one can provide end-to-end communication flexibility and potentially retain identity information for repudiation. As a proof of concept, a prototype has been developed to simulate an IoT software client with the capability of hosting a CoAP RESTful service. The prototype studies data requests via a network client establishing a TLS over JSON session using a hosted CoAP RESTful service. To prove reputability and integrity of TLS JSON messages, JSON messages was intercepted and verified against simulated MITM attacks. The experimental results confirm that TLS over JSON works as hypothesised.

• 정보보호학회논문지
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• 제14권3호
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• pp.145-153
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• 2004

디지털 핑거프린팅(digital fingerprinting)은 멀티미디어 컨텐츠에 구매자의 정보를 삽입함으로 컨텐츠를 불법적으로 재분배하는 부정자를 추적하는 방법이다. Domingo가 최초로 제안한 COT(committed oblivious transfer) 기반의 핑거프린팅 방식은 핑거프린팅 단계의 계산적 복잡도를 완전히 분석하여 기존의 MDPK(minimum disclosure proof of knowledge)나 SWPC(secure multi-party computation)등에 기반한 방식들에 비해 구현 가능성을 높였다는 의의를 지닌다. 그러나 이 방식은 판매자의 부정에 안전하지 못하다는 문제점이 있다. 본 논문에서는 첫째, 두 가지 COT기반의 디지털 핑거프린팅 방식의 문제점을 지적하고, 둘째, 이것의 해결을 위해 이중 잠금 암호(two-lock cryptosystem) 시스템을 사용한 불확정 전송 프로토콜 기반의 디지털 핑거프린팅 기법을 제안한다. 제안방식은 기존의 COT 기반 방식에서 안전성과 식별 단계의 효율성을 개선하였다.

• 정보보호학회논문지
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• 제15권5호
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• pp.73-92
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• 2005

Joux의 3자 키 교환 프로토콜은 키 합의 분야에서 가장 뛰어난 업적 가운데 하나이다. 하지만 Joux 프로토콜은 인증 기능을 제공하지 않아 man-in-the-middle 공격에 취약하다. 비록 Joux 프로토콜에 대하여 인증서 기반 그리고 ID 기반 인증기법이 제안되었지만, 아직 1 라운드에 실행되는 안전성이 증명 가능한 패스워드 기반 3자 키 교환 프로토콜은 제안된 바 없다. 본 논문에서는 Joux 프로토콜에 EC-PAK의 패스워드 인증 기법을 적용하여 안전성이 증명 가능한 1 라운드 3자 키 교환 프로토콜을 제안하였다. 그리고 렌덤 오라클 모델을 사용하여 프로토콜의 안전성도 증명하였다.

• 한국통신학회논문지
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• 제42권4호
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• pp.838-847
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• 2017

최근 마이크로소프트사의 CAPI를 대체하기 위해 제안된 CNG는 플러그인 구조 기반의 독립된 모듈들로 구성되어 있기 때문에 개발비용과 확장 용이성 부분에서 우수하다. 하지만 이러한 이점과 반대로 보안성에 대한 고려는 다소 부족하며, 현재 CNG가 배포되어 활용되고 있는 상황에서 이와 관련된 연구는 반드시 필요하다. 이에 본 논문에서는 CNG에서 발생 가능한 보안 취약점을 분석하였다. 분석된 취약점을 토대로 개념 검증 도구를 구현하여 이를 검증하였다. 검증 결과는 CNG를 활용하는 Outlook 프로그램과 Internet Explorer 프로그램에서 메일 및 계정정보의 탈취, Amazon, E-bay, Google, Facebook 웹 사이트의 계정정보의 탈취가 가능하였다. 본 논문의 결과는 CNG를 활용하는 다양한 응용의 보안성을 향상시키는데 기여할 것으로 사료된다.