• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1387-1394
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• 2000

The SSL(Secure Socket Layer) protocol is one of the mechanism widely used in the recent network system. The improved information security mechanism based on the SSL is designed in this paper. There are important four information security services. The first is the authentication service using the Certificate offered from the SSL(Secure Socket Layer), the second is the message confidentiality service using the DES encryption algorithm, the third is the message integrity service using Hash function, and the fourth is Non-repudiation service. Therefore, information could be transferred securely under the information security mechanism including Non-repudiation service especially designed in this paper.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.204-214
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• 1999

The user authentication service can be used to prevent telecommunications piracy and to demand reliable payment from subscriber. Over the last few years several of the cryptographic systems being used by the IS-41 North American Mobile telephones have been broken. These algorithms included ORYX, CMEA and CAVE. The process of replacing these algorithms is already underway. In this paper we designed a hash function and applied it to the authentication algorithm of IS-95A authentication system. We also analyzed the randomness properties of designed algorithm using statistical analysis and simulated the validity of this algorithm using C programming language.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.441-448
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• 2020

With help of Vehicle-to-Grid(V2G) technology battery in electric vehicle can be used as distributed energy resource and energy storage in a smart grid environment. Several problems of security vulnerability and privacy preservation can be occurred because V2G network supports 2 way communication among all components. This paper explains and makes analysis of architecture, privacy sensitive data, security vulnerability and security requirement of V2G system. Furthermore efficient architecture and operating scheme for V2G system are proposed. This scheme uses symmetric cryptosystem and hash algorithm to support privacy preservation and mutual authentication.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.3
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• pp.107-115
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• 2004

SHACAL-2 is a 256 bit block cipher with various key sizes based on the hash function SHA-2. Recently, it was recommended as one of the NESSIE selections. UP to now, no security flaws have been found in SHACAL-2. In this paper, we discuss the security of SHACAL-2 against an impossible differential attack. We propose two types of 14 round impossible characteristics and using them we attack 30 round SHACAL-2 with 512 bit 18y. This attack requires 744 chosen plaintexs and has time complexity of 2$^{495.1}$ 30 round SHACAL-2 encryptions.

• Review of KIISC
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• v.20 no.6
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• pp.43-50
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• 2010

병렬처리를 이용한 GPU(그래픽 프로세싱 유닛)의 연산 능력이 날이 갈수록 고속화됨에 따라 GPU에 대한 관심이 높아지고 있다. GPU는 다중 쓰레드 처리가 가능하도록 CPU보다 수십 배 많은 멀티코어로 구성되어 있으며 이 각각의 코어는 맹렬 프로그래밍이 가능하도록 처리 결과를 공유할 수 있다. 최근 해외에서 이러한 GPU의 연산 능력을 이용한 해쉬인증 공격의 효과가 다수 입증되었으며 패스워드 기반의 인증 방식이 보편화 되어있는 국내에서도 GPU를 이용한 인증 공격이 시도되고 있다. 본 논문에서는 국내 금융권에서 사용되고 있는 공인인증서의 개인키 복호화 과정을 GPU내에서 고속 수행이 가능하도록 개선하고, 이를 바탕으로 패스워드 무차별 대입 공격을 시도하여 공인 인증서에 사용되는 패스워드가 보안의 안전지대만이 아님을 보인다. 또한 날로 발전하는 하드웨어의 연산속도에 맞추어 공인인증서 등에 보편적으로 사용되는 패스워드 정책의 개선 방안을 제시한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05d
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• pp.1127-1132
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• 2002

LFSR보다 CA가 랜덤성이 우수한 패턴들을 효율적으로 생성함이 알려지면서 그 응용분야가 점차적으로 확대되어가고 있다. Nongroup CA는 해쉬함수의 생성, 암호알고리즘, 이미지 압축 등에 응용되고 있다. 그러나 CA가 생성하는 패턴의 분석이 용이하지 못하였다. 본 논문에서는 선형 nongroup CA의 일반적인 성질과 여원 벡터가 선형 nongroup CA의 0-트리의 0이 아닌 상태인 경우 이로부터 유도되는 여원 TPNCA의 상태들의 행동을 분석하였다.

• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.679-686
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• 2012

Many researches have proposed key management schemes for Smartgrid System. However, previous studies lack the proper considerations for availability and device security. In this paper, we build up cryptographic security improvement for robust Smartgrid Systems. In addition, we propose a public-key management and hash function architecture for robust Smartgrid Systems which supports reduces the number of key and Secure Device in AMI network environments.

• Journal of Korea Multimedia Society
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• v.6 no.3
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• pp.549-555
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• 2003

CA is cost-effective to generate pseudorandom patterns than LFSR. Based on the effectiveness of a CA based pseudorandom pattern generator, CA have been employed successfully in several applications. Especially Nongroup CA is applied to efficient hash function generation, cryptography and image compression. In this paper we analyze the properties of TPNCA and by using basic paths in the 0-tree of a linear TPNCA we analyze the structure of the state-transition graph. Also by showing the structure of the complemented CA which have the acyclic state of the 0-tree as the complement vector is isomorphic to the structure of the original TPNCA, we reduce the time in analyzing the CA-states.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.318-323
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• 2000

The SSL(Secure Socket Layer) protocol is one of the mechanism widely used in the recent network system. The improved information security mechanism based on the SSL is designed in this paper. There are important four information security services. The first is the authentication service using the Certificate offered from the SSL(Secure Socket Layer), the second is the message confidentiality service using the DES encryption algorithm, the third is the message integrity service using Hash function, and the fourth is Non-repudiation service. Therefore, information could be transferred securely under the information security mechanism including Non-repudiation service especially designed in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8B
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• pp.1028-1037
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• 2011

Recently, Selim et al proposed public key cryptography based privacy preserving multi-context RFID authentication protocol. However Selim et al's proposed protocol not only doesn't fit into passive tag based RFID system because it uses public key based encryption algorithm to perform authentication between reader and tag, but also is insecure to an impersonation attack because it doesn't provide mutual authentication. In order to eliminate the above described efficiency problem and security vulnerabilities, this paper proposes a new multi-context RFID mutual authentication protocol that can prevent privacy invasion and tag impersonation attack through providing mutual authentication between single passive tag which is located different application space and readers which provide multi-context purposes and can secure against relay attack and denial-of-service attack. As a result, the proposed protocol performs secure mutual authentication based on the collected space and time information from the RFID reader and provides strong security and high computation efficiency because if performs secure one-way hash function and symmetric encryption operations suitable to the environments of passive RFID tags.