• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.598-601
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• 2003

초고속 통신망을 이용한 인터넷의 대중화와 더불어 인터넷을 기반으로 하는 SNMP가 활발해 지고 있다. SNMP에 있어서는 민감한 정보의 기밀성과 사용자 인중의 확보가 필수적이며, 이를 위해서는 전자서명 기술을 포함하고 있는 공개키 기반의 인증서 관리 체계의 확립이 선결되어야 한다. 본 논문에서는 인증, 기밀성 및 무결성 문제를 해결하기 위하여 PKI 기반 인증서의 생성, 관리 기능과 인증서를 상호 교환하여 매매 협상을 하는 에이전트 중재에 의한 보안 애플리케이션을 설계하고 이에 대하여 기술한다.

• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.133-140
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• 2003

IKE, which is the standard key management protocol for IPSEC, is said to have several known problems. To resolve the problems of the IKE, two protocol proposals are being discussed in the IETF. the IKE version 2 and Just Fast Keying protocols. They should satisfy several protocol design requirements such as the protocol simplicity, the endurability against DOS attacks, the degree of the PFS, the identity protection, the cryptographic negotiation, and the authentication methods. In this paper, we summarize the characteristics of these two protocols and try to analyze their implications according to the protocol design requirements.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11B
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• pp.1005-1016
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• 2006

As the increment usage of Internet, the security systems's importance is emphasized. The current Internet Key Exchange protocol(IKE) which has been used for key exchange of security system, was pointed out a problem of efficiency and stability. In this research, we try to resolve those problems, and evaluate the newly designed Key Exchange protocol in the IPsec interaction test bed system environment. In this research we implemented the new Key Exchange Protocol as a recommendation of RFC proposal, so as to resolve the problem which was pointed out the key exchange complexity and the speed of authentication process. We also designed the defense mechanism against the Denial of Service attack. We improved the key exchange speed as a result of simplification of complex key exchange phase, and increased efficiency as a result of reuse the preexistence state value when it's renegotiated.

• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.75-81
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• 2003

User authentication, including confidentiality, integrity over untrusted networks, is an important part of security for systems that allow remote access. Using human-memorable Password for remote user authentication is not easy due to the low entropy of the password, which constrained by the memory of the user. This paper presents a new password authentication and key agreement protocol suitable for authenticating users and exchanging keys over an insecure channel. The new protocol resists the dictionary attack and offers perfect forward secrecy, which means that revealing the password to an attacher does not help him obtain the session keys of past sessions against future compromises. Additionally user passwords are stored in a form that is not plaintext-equivalent to the password itself, so an attacker who captures the password database cannot use it directly to compromise security and gain immediate access to the server. It does not have to resort to a PKI or trusted third party such as a key server or arbitrator So no keys and certificates stored on the users computer. Further desirable properties are to minimize setup time by keeping the number of flows and the computation time. This is very useful in application which secure password authentication is required such as home banking through web, SSL, SET, IPSEC, telnet, ftp, and user mobile situation.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.2165-2168
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• 2002

초고속 통신망을 이용한 인터넷의 대중화와 더불어 인터넷을 기반으로 하는 e-Commerce 가 활발해지고 있다. e-Commerce 에 있어서 민감한 정보의 기밀성과 사용자 인증의 확보가 필수적이며, 이를 위해서는 전자 서명 기술을 포함하고 있는 공개키 기반의 인증서 관리 체계의 확립이 선결되어야 한다. 본 논문에서는 인증, 기밀성 및 무결성 문제를 해결하기 위해 PKI 기반 인증서의 생성, 관리 기능과 인증서를 상호 교환하여 매매 협상을 하는 에이전트 중재에 의한 SecuPmart 보안 애플리케이션을 설계하고 이에 대하여 기술한다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.793-795
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• 2001

IPSec은 IETF에 의해 IP 레이어 보안을 위한 개방형 구조로 설계된 것으로 인터넷에서의 정보보호를 대표한다. 그리고 ISKMP는 인터넷에서 요구되는 정보보호를 설정하기 위한 인증, 키 관리 및 보안협상등을 담당하는 프로토콜로써 IPSec으로 보다 체계화된 인터넷 정보보호를 제공하기 위해 포함되어야 하는 IKE에서 사용하는 프로토콜이다. 이러한 IPSec을 이용한 보안 시스템을 개발하기 위해서는 시스템에서 사용하고 있는 프로토콜들에 대한 평가 방법도 같이 제시되어야 하나, 기존의 프로토콜 분석 도구들은 IPSec에서 제공하고 있는 프로토콜들을 분석하지 못할 뿐만 아니라 개발단계에서의 구현 평가를 하지 못한다. 본 논문에서는 IPSec을 구현하는데 필요한 AH 및 ESP 프로토콜과 ISAKMP 프로토콜을 실시간으로 분석하고, 이들 프로토콜들이 얼마나 잘 구현되었는지를 평가할 수 있는 프로토콜 분석 도구를 설계하고 구현하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.769-776
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• 2016

TELNET is vulnerable to network attack because it was designed without considering security. SSL/TLS and SSH are used to solve this problem. However it needs additional secure protocol and has no backward compatibility with existing TELNET in this way. In this paper, we have suggested STELNET(Secured Telnet) which supports security functionalities internally so that has a backward compatibility. STELNET supports a backward compatibility with existing TELNET through option negotiation. On STELNET, A client authenticates server by a certificate or digital signature generated by using ECDSA. After server is authenticated, two hosts generate a session key by ECDH algorithm. And then by using the key, they encrypt data with AES and generate HMAC by using SHA-256. After then they transmit encrypted data and generated HMAC. In conclusion, STELNET which has a backward compatibility with existing TELNET defends MITM(Man-In-The-Middle) attack and supports security functionalities ensuring confidentiality and integrity of transmitted data.

• Journal of Korea Multimedia Society
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• v.15 no.8
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• pp.1048-1058
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• 2012

This paper proposes the DDMPF(Distributed Data Management Protocol using FAT) which prevents data loss and keeps the security of self-organized storages by comprising a client, a storage server, and a verification server in clouding environment. The DDMPF builds a self-organized storage server, solves data loss by decentralizing the partitioned data in it in contrast to the centralized problem and the data loss caused by the storage server problems of existing clouding storages, and improves the efficiency of distributed data management with FAT(File Allocation Table). And, the DDMPF improves the reliability of data by a verification server's verifying the data integrity of a storage server, and strengthens the security in double encryption with a client's private key and the system's master key using EC-DH algorithm. Additionally, the DDMPF limits the number of verification servers and detects the flooding attack by setting the TS(Time Stamp) for a verification request message and the replay attack by using the nonce value generated newly, whenever the verification is requested.

• Journal of Educational Research in Mathematics
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• v.13 no.4
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• pp.463-483
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• 2003

In the learning of mathematics, students experience the semiotic activities of representing and interpreting mathematical signs. We called these activities as the representing and interpreting of mathematical signs. On the foundation of Peirce's three elements of the sign, we analysed that students constructed the representamen to interpret the concept of correlation as for the object, "as one is taller, one's size of foot is larger" 4 middle school students who participated the gifted center in Seoul, arranged the statistical data, constructed their own representamen, and then learned the conventional signs as a result of the whole class discussion. In the process, students performed the detailed representing and interpreting of signs, depended on the templates of the known signs, and interpreted the process voluntarily. As the semiotic activities were taken place in this way, it was needed that mathematics teacher guided the representing and interpreting of mathematical signs so that the representation and the meaning of the sign were constructed each other, and that students endeavored to get the negotiation of the interpretants and the representamens, and to reach the conventional representing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.382-389
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• 2009

As the use of mobile device is popularized, the needs of variable services of WiMAX technique and the importance of security is increasing. There is a problem that can be easily attacked from a malicious attack because the action is achieved connectionlessly between neighbor link establishing procedure and TEK exchange procedure in mobile WiMAX even though typical 1 hop network security technique is adapted to WiMAX for satisfying these security requirement. In this paper, security connected mechanism which safely connects neighbor link establishing procedure of WiMAX and TEK exchange procedure additional to the basic function provided by IEEE 802.16e standard to satisfy security requirement of mobile WiMAX is proposed. The proposed mechanism strengthens the function of security about SS and BS by application random number and private value which generated by SS and BS to public key of neighbor link establishing procedure and TEK exchange procedure. Also, we can prevent from inside attack like man-in-the-middle which can occur in the request of TEK through cryptographic connection of neighbor link establishing procedure and TEK exchange procedure.