• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.32-40
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• 2001

In this paper, we propose a high-speed modular multiplication algorithm which revises conventional Montgomery's algorithm. A hardware architecture is also presented to implement 1024-bit RSA cryptosystem for digital signature based on the proposed algorithm. Each iteration in our approach requires only one addition operation for two n-bit integers, while that in Montgomery's requires two addition operations for three n-bit integers. The system which is modelled in VHDL(VHSIC Hardware Description Language) is simulated in functionally through the use of $Synopsys^{TM}$ tools on a Axil-320 workstation, where Altera 10K libraries are used for logic synthesis. For FPGA implementation, timing simulation is also performed through the use of Altera MAX + PLUS II. Experimental results show that the proposed RSA cryptosystem has distinctive features that not only computation speed is faster but also hardware area is drastically reduced compared to conventional approach.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6282-6289
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• 2015

Today, there is an increasing number of cases in which certificate information is leak, and accordingly, electronic finance frauds are prevailing. As certificate and private key a file-based medium, are easily accessible and duplicated, they are vulnerable to information leaking crimes by cyber-attack using malignant codes such as pharming, phishing and smishing. Therefore, the use of security token and storage toke' has been encouraged as they are much safer medium, but the actual users are only minimal due to the reasons such as the risk of loss, high costs and so on. This thesis, in an effort to solve above-mentioned problems and to complement the shortcomings, proposes a system in which digital signature for Internet banking can be made with a simply bio-authentication process. In conclusion, it was found that the newly proposed system showed a better capability in handling financial transitions in terms of safety and convenience.

• Journal of Korean Library and Information Science Society
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• v.36 no.2
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• pp.327-348
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• 2005

The purpose of this study is to emphasize the importance of index definition and to prepare the basis of optimal index in bibliographic retrieval system. For the purpose, this research studied a index extraction theory on index tag definition and index normalization from the bibliographic marc database and analyzed a retrieval utilization rate of extracted index. In this experiment, we divided index between text-type and code-type about the generated 29,219,853 indexes from 2,200,488 bibliographic records and analyzed utilization rate by the comparison of index-type and index term of web logs. According to the result, the text-type indexes such as title, author, publication, subject are showed high utilization rate while the code-type indexes were showed low utilization rate. So this study suggests that the unused index is removed from index definition to optimize index.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1479-1485
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• 2008

This paper shows the result of study on the detailed applicable procedure of software Escrow account applied for rolling stock. The customer as end-user requires software source code, related critical technical documents etc. about software based system of train for maintenance purpose through software modification and enhancement after completion of warranty period. Otherwise, it is not easy to keep up with the customer's requirement of demanding supplier's exclusive information because it is considered as intellectual property rights of supplier as software developer. Therefore, the main contractor(normally called as Car-builder) need to introduce software Escrow service in order to coordinate the different a standpoint between software developer and end-user. Software Escrow is a legal arrangement in which an software Escrow packages (software source code, software development tool, build process, proprietary information, copyright and etc.) is deposited into and Escrow account under the trust of a reliable third party (Escrow agent) depending on mutual agreement on Escrow contract condition as signing off Escrow agreement document. This paper deals with the study on the detailed procedure about the following general category of Escrow procedure and purpose to apply this specific procedure of Escrow into the future project onward.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.5
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• pp.1015-1022
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• 2012

This paper deals with hardware design which unifies MD5 and HAS-160 hash algorithms. Two algorithms get a message with arbitrary length and process message blocks divided into 512 bits each time and output a hash code with a fixed length. MD5 ouputs a hash code of 128 bits and HAS-160 a hash code of 160 bits. The unified hash core designed has 32% of slices overhead compared to HAS-160 core. However, there is only a fixed message buffer space used. The unified hash core which run a step in one clock cycle operates at 92MHz and has performance which digests a message in the speed of 724Mbps at MD5 and 581Mbps at HAS-160 hash mode. The unified hash core which is designed can be applicable to the areas such as E-commerce, data integrity and digital signature.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1997.11a
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• pp.91-100
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• 1997

암호학적으로 안전한 해쉬 함수는 디지털 서명, 메시지 인증, 키 유도와 같은 분야에서 중요한 암호 도구이다 현재까지 제안된 소프트웨어로 고속 수행이 가능한 해쉬 함수들의 대부분은 Rivest가 제안한 MD4의 설계 원리에 기반을 두고 있다. 이들 MD 계열 해쉬 함수 중에서 현재 안전하다고 알려진 전용 해쉬 함수는 SHA-1, RIPEMD-160, HAVAL 등이다. 본 논문에서는 이들 세 가지 해쉬 함수들의 장점에 기반하여 이들 함수들이 가지는 안전성을 최대한 유지하면서 보다 효율적인 새로운 해쉬 함수를 제안한다. 제안된 해쉬 함수는 임의 길이 메시지를 512비트 단위로 처리하여 160비트의 출력을 가지며, 입력 데이터에 의존한 순환이동(data-dependent rotation)의 특징을 가짐으로써 기존에 알려진 공격에 강인함을 보장한다. 또한 제안된 해쉬 함수를 이용한 메시지 인증 코드(Message Authentication Code:MAC) 구성 알고리즘을 제안한다 MAC은 두 번째 입력, 즉 비밀키를 가진 해쉬 함수로 keyed 해쉬 함수라고 하며, 메시지 출처 인증과 무결성 확인을 제공한다. 제안된 MAC은 최대 160-비트의 키를 사용하며 해쉬 결과보다 같거나 적은 MAC 결과를 가지며, 성능 면에서 사용되는 해쉬 함수에 비해 약 10% 정도의 저하를 초래한다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.1
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• pp.29-34
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• 2008

A wavelet-based image watermarking scheme is proposed, based on the insertion of pseudo-random codes in the frequency domain. The original image is required for the watermark detection. The "strength" of the signature to be embedded depends on the image to be marked, thus fitting signal capacity. The experimental results prove that the method is more tamper resistant and less perceptible for any type of images than other well-known private methods in the frequency domains.

• Information and Communications Magazine
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• v.29 no.2
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• pp.30-38
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• 2012

차량용 무선 통신이 처음 제안된 이래 다양한 자동차 생산 기업에서 차량에 무선통신 설비를 설치하고자 하고 있으며, 여러 국가에서 차량 무선통신을 위한 인프라 설치를 논의하고 있다. 따라서 수 년 내에 실생활에서 차량용 무선 통신을 이용 가능할 것으로 전망된다. 차량용 무선 통신을 이용하여 차량의 상태를 전송할 수 있고, 각종 교통 정보를 전송 받을 수도 있기 때문에 교통이 보다 안전하고 원활해 질 것이다. 하지만, 차량용 무선 통신에서 전송되는 데이터는 차량의 위치나 상태와 같은 개인 정보를 많이 포함하고 있다. 따라서 전송되는 메시지들의 보안과 그 메시지의 송신자에 대한 익명성이 보장되어야 한다. 그러나 익명성만 보장된 경우, 허위 정보나 악성 코드가 전송되었을 때, 이를 보낸 차량이 어떤 것인지 판별할 수 없게 되는데, 이를 보완하기 위하여 전송되는 메시지의 송신자를 추적할 수 있는 장치가 펼요하다. 그리고 차량용 무선 통신에 참여하는 차량의 수가 늘어날수록 전송되는 데이터도 폭발적으로 증가하는데, 이들을 효율적으로 인증할 수 있는 시스템 역시 갖춰져야 한다. 본 고에서는 차량용 무선통신에서 전송되는 정보에 대하여, 송신자의 익명성 보장과 효율적인 일괄 메시지 인증, 그리고 송신자 추적을 제공하는 차량용 디지털 서명 기술을 소개하고자 한다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.1
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• pp.41-46
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• 2016

It has been proven that the dissolved gas analysis (DGA) is the most effective and convenient method to diagnose the transformers. The DGA is a simple, inexpensive, and non intrusive technique. Among the various diagnosis methods, IEC 60599 has been widely used in transformer in service. But this method cannot offer accurate diagnosis for all the faults. This paper proposes a fault diagnosis method of oil-filled power transformers using IEC code based neuro-fuzzy model. The proposed method proceeds two steps. First, IEC 60599 method is applied to diagnosis. If IEC code can't determine the fault type, neuro-fuzzy model is applied to effectively classify the fault type. To demonstrate the validity of the proposed method, experiment is performed and its results are illustrated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1469-1474
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• 2004

A wavelet-based image watermarking scheme is proposed, based on the insertion of pseudo-random codes in the frequency domain. The original image is required for the watermark detection. The 'strength' of the signature to be embedded depends on the image to be marked, thus fitting signal capacity. The experimental results prove that the method is more tamper resistant and less perceptible for any type of images than other well-known private methods in the frequency domains.