• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.57-62
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• 2017

With various sensors and communications capabilities, the Internet is growing larger as the internet can communicate with the Internet. Given the growing vulnerability of the internet market, the development of security and security is increasing, and the development of the internet is actively evolving and the development of the internet is actively being carried out. In particular, it is required to introduce lightweight and secure authentication schemes, especially those that are difficult to use due to the difficulty of using authentication schemes. Thus, the safety of the secure authentication system of the Internet is becoming very important. Therefore, in this thesis, we propose certification technologies on secure objects to ensure correct, safe communication in the context of the internet context.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.3685-3691
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• 2015

We developed the platform safety step system for the passenger to avoid misstep accident and secure the pedestrian safety. In this study, we classify platform safety step system into hierarchy system and predict the failure rate of each part and calculate the failure rate & MTBF(Mean Time Between Failure) of each module(sub-system) by means of RBD(Reliability Block Diagram) & FTA(Fault Tree Analysis). Finally, we will propose the reliability analysis results for RAMS analysis of platform safety step system.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.675-678
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• 2013

암호 알고리즘이 탑재된 환경에서 암호 알고리즘의 이론적 안전성이 고려되어도 환경에 의존한 부가적 정보를 활용하는 부채널 분석에 대한 안전성이 검토되어야 한다. 최근까지 부채널 분석에 대한 안전성을 고려한 대응기법으로 마스킹 기법이 적용되었으나, 이와는 상반된 개념인 하드웨어 DPL(Dual-rail with Precharge Logic) 기법을 응용한 균일한 해밍웨이트를 제공하는 소프트웨어 AES(Advanced Encryption Standard)가 제안되었다. 최근, 소프트웨어 기반 블록암호에 대해 고차 마스킹 부채널 대응법의 비효율성으로 새로운 방법에 대한 다양한 시도가 되고 있으며, 그 중 균일한 해밍웨이트를 제공하는 표현 방법이 효율적이고 안전한 새로운 대응법으로 검토되어지고 있다. 하지만, 논문에서는 균일한 해밍웨이트 데이터 표현방법 기반 부채널 대응법을 해독하는 차분전력분석 방법을 소개한다. 실험을 통해, AES 128비트 키 중 일부분이 분석됨을 확인하였다. 이는 공격자가 테이블 변환 정보를 활용할 수 있다는 다소 강력한 가정하에 실험하였기 때문이다. 앞선 가정 하에 안전성을 제공하기 위해서는 차후 추가적 대응기법이 고려되어야 한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.4
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• pp.55-66
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• 2001

In this paper, we analyze the security of OFB encryption mode which is one of the basic modes of operation for the block cipher and the security of 3GPP f8 encryption mode used to provide the data confidentiality over a radio access link of W-CDMA IMT-2000. We provide the lower bound and the upper bound on security of both modes in random function model and random permutation model, respectively, by means of the left-or-right security notion, and prove the security of both modes using a pseudorandom function and a pseudorandom permutation, respectively.

• Journal of KIISE:Software and Applications
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• v.35 no.3
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• pp.149-161
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• 2008

As Programmable Logic Controllers(PLCs) are frequently used to implement real-time safety critical software, testing of PLC software is getting more important. We propose a structural testing technique on Function Block Diagram(FBD) which is one of the PLC programming languages. In order to test FBD networks, we define templates for function blocks including timer function blocks and propose an algorithm based on the templates to transform a unit FBD into a flowgraph. We generate test cases by applying existing testing techniques to the generated flowgraph. While the existing FBD testing technique do not consider infernal structure of FBD to generate test cases and can be applied only to FBD from which the specific intermediate model can be generated, this approach has advantages of systematic test case generation considering infernal structure of FBD and applicability to any FBD without regard to its intermediate format. Especially, the proposed method enables FBD networks including timer function blocks to be tested thoroughly. To demonstrate the effectiveness of the proposed method, we use trip logic of bistable processor of digital nuclear power plant protection systems which is being developed in Korea.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.9
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• pp.819-831
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• 2019

The types of properties traded in modern times are rapidly increasing due to changes in consumption patterns. However, as the type of properties traded increases, estimation about the value of properties may become inaccurate. There is a problem that it is difficult for consumers to estimate the right value and the variety of trading forms makes it difficult to guarantee the reliability of value estimation As access to a variety of properties has expanded, these shortcomings are considered to be a factor that hinders the stability of the shared economic market. In this paper, to resolve this issue, we present a blockchain-based property contract service through a trusted broker. The developed service registers trusted brokers into smart contracts on the Ethereum blockchain and use them for the evaluation and contract process of properties. In addition, registered contents, proposals and contracts of properties are stored in the blockchain to ensure the reliability of the contract process. Every step of the contract process is stored in the smart contract, recorded in the transaction history of the blockchain, ensuring the reliability of the stored data. In addition, the entire process of registration, proposal, and contract is driven by smart contracts designed by state machine technology, enabling users to more securely control the contract process.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.633-640
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• 2023

In this study, numerical analysis was performed based on field investigation to derive an appropriate reinforcement method by analyzing the displacement behavior characteristics of concrete blocks generated in the direct fixation track on the bridges of the serviced light rail transit. The track of this study was a direct fixation track on a sharp curved track, and the problem of movement of the concrete blocks installed on the bridge deck in the longitudinal and lateral directions occurred. In this study, based on the finite element model using 3D solid elements, the behavior of the direct fixation track that could be occurred under operating load conditions was analyzed. In addition, the reinforcement effect of various reinforcement methods was analyzed. As a result of analyzing the lateral displacement before and after reinforcement, it was analyzed that the maximum lateral displacement after reinforcement under the extreme lateral wheel loads significantly decreased to about 3% (about 0.1mm) compared to before reinforcement. In addition, as a result of examining the generated stress of the filling mortar, bridge decks, and reinforcing bar, it was analyzed that all of them secured a sufficient safety factor of 2.6 or higher, and the optimal conditions for the reinforcement method were derived. Therefore, it is judged that the number of anchoring reinforcements and symmetrical anchor placement reviewed in this study will be effective in controlling the occurrence of lateral displacement of concrete blocks and securing the structural integrity of bridges and concrete blocks.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.523-525
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• 2004

컴포넌트 지향 개발 방법이 도입되면서 많은 분산환경하에 컴포넌트들이 상호 연동하여 사용되어지기 시작했다. 그러나 분산환경에서의 상호연동은 많은 어려움과 과제를 우리에게 안겨주었다. 이를 보안하여 상호운영성을 고려한 웹 서비스의 개념이 나오기 시작하고 있다. 웹 서비스는 이기종간의 컴포넌트 서비스를 쉽게 구현할 수 있게 하며 컴포넌트들을 이용에 블록을 쌓듯이 애플리케이션을 만들 수 있다. 그러나 웹 서비스는 아직 QoS 문제가 남아있다. 웹 서비스의 품질을 보장하고 사용자가 웹 서비스를 안전하게 사용하기 위해서는 QoS 기반 컴포넌트 조립이 필수적이다. 본 논문은 로컬 브로커와 XML-QoS 스키마를 사용하여 사용자가 QoS를 고려한 실행 계획을 세울 수 있게 한다.

• Review of KIISC
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• v.6 no.1
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• pp.65-78
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• 1996

본 논문에서는 JPEG 알고리즘을 이용하여 화상데이터를 부호화할때 디지털 서명문과 같은 기밀 데이터를 몰래 집어넣어 합성하는 방식에 대하여 고찰한다 그 기본원리는 DCT 계수를 양자화 할 때 필연적으로 생기는 오차를 이용하는 것으로 0이 아닌 양자화 계수를 합성하고자 하는 기밀데이터에 따라 근처의 정수로 조절하는 것이다. 이 방식을 SIDBA 표준화상에 적용하여 화상의 열화는 무시할 정도로 작으면서 원하는 크기의 기밀 데이터를 합성할 수 있음을 보인다. 또한, 화질의 열화를 최소화시키면서 일정량의 기밀 데이터를 합성시키기 위하여 블록당 1화소를 적절히 선택하여 제3자의 공격에 대한 안전성을 향상시키는 방법을 제시하고 컴퓨터 시뮬레이션을 통하여 성능을 분석한다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.190-194
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• 2003

이 논문에서는 블록 암호 알고리즘인 XTEA에 관한 연관키를 이용한 차분공격에 대하여 설명한다. 이것은 XTEA 알고리즘이 TEA가 갖고 있는 취약한 키 스케줄을 보완하여 Kelsey 등이 제안한 연관키 공격에 대응하기 위하여 설계되었지만, 26 라운드로 줄인 XTEA 또한 우리의 연관키를 이용한 차분공격에 안전하지 못하다는 것을 보여준다. 또한 키 스케줄에 의하여 다양하게 변화된 라운드의 XTEA에 관한 연관키 공격이 가능하다. 이 때 필요한 선택평문과 암호화 과정은 각각 2$^{18.5}$ 과 2$^{115.21}$ 이다.