• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.177-182
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• 2004

The existing group key management architectures applied to a small scale routing protocols may have many overheads with key distribution. Therefore this paper proposes a group key management protocol in PIM-SM multicast group communication. This method divide multicast groups with RP, and subgroup key managers are established in each RP and can be transmitted groups keys. And this does not have needs of the data translation and the new key distribution for path change. This does not have needs of the data translation and the new key distribution for path change, so the data transmission time can be reduced.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7C
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• pp.733-742
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• 2003

Unlikely unicast transmission, there are many elements that threaten security. Thus, key management of creating and distributing group keys to authorized group members is a critical aspect of secure multicast operations. To offer security in multicast environment, the recent researches are related to most group key distribution. In this thesis, we propose a group key management protocol for efficient, scalable, and multicast operation. This proposed protocol architecture can distribute traffic centralized to the key server. since the group key rekeyed by sub-group manager. The detailed simulation compared with other group key management protocol show that the proposed group key management protocol is better for join, leave, and data latency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8B
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• pp.730-735
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• 2006

This paper proposes a media key distribution scheme for lawful interception in secured VoIP systems. A problem of the current US or EU standards for lawful interception is that they do not provide a mechanism for collecting keys used for encrypting media streams between two end points. In the proposed scheme, dual encryption was applied on the media keys using two shared secrets: one between the ISP AAA server and user agent, and the other between the TSP registrar and user agent. Only the lawful agency with court warrant can collect both keys from the service providers. This scheme can still provide a privacy by preventing the misusage of the keys by the service providers.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1994.11a
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• pp.108-117
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• 1994

본 논문에서는 공개키방식 알고리즘과 대칭키방식 알고리즘을 혼합하여 사용하는 혼합방식 암호시스템 (CHyCK:Certificate-based Hybrid Cryptosystem of KAIST) 의 구현에 대해 설명한다. CHyCK는 전송하고자 하는 메세지를 대칭키 암호알고리즘을 이용해서 암호화하고 이 때에 사용되는 대칭키를 공개키방식으로 암호화하여 상대방에게 암호화된 메세지와 함께 보내게 된다. CHyCK는 공개키방식에서 사용되는 키쌍 중 공개키를 안전하게 가입자에게 분배해 주는 방법으로 인증서기반(certificate-based)방식 을 채택하였다. 또한 이를 위해서는 인증서를 발급해 줄 인증기관(certifying authority)이 필요하게 된다. 그리고 시스템을 구성하는 기본 암호알고리즘들은 기존의 것들 중 적합한 것으로 선택했다. 마지막으로 본 논문에서는 시스템의 안전성을 키분배와 메세지 전송 측면에서 분석했다.

• Journal of KIISE:Information Networking
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• v.30 no.6
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• pp.705-713
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• 2003

For group security to protect group data or to charge, group keys should be updated via key update messages when the membership of group changes. If we lose these messages, it is not possible to decrypt the group data and so this is why the recovery of lost keys is very significant. Any message lost during a certain member is logged off can not be recovered in real-time. Saving all messages and resending them by KDC (Key Distribution Center) not only requests large saving spaces, but also causes to transmit and decrypt unnecessary keys. This paper analyzes the problem of the loss of key update messages along with other problems that may arise during member login procedure, and also gives an efficient method for recovering group keys and auxiliary keys. This method provides that group keys and auxiliary keys can be recovered and sent effectively using information stored in key-tree. The group key generation method presented in this paper is simple and enable us to recover any group key without storing. It also eliminates the transmissions and decryptions of useless auxiliary keys.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1992.11a
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• pp.181-189
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• 1992

IEEE 802, 10 의 SILS 키이관리 응용에 적용될 수 있는 D-H 형태의 키이분배 시스템을 제안한다. 제안된 키이 분배방식에서는 신분 인중과 키이 생성이 동시에 수행되며, 멱숭 연산도 2번만이 필요하다. 그리고 전체 프로토콜의 수행은 3-way 통신으로 이루어진다. 본 연구에서 제안하는 상호 신분 인중 및 키이 분배 방식은 비밀 키이의 소유자만이 상호 통신의 결과로 생성된 키이 값을 정확히 알 수 있다는 사실을 바탕으로 한다. 이와 같은 인중과 키이 분배 기능을 동시에 수행하는 프로토콜은 LAN 과 같은 통신망에 아주 적합한 키이 분배 시스템이다.

• The KIPS Transactions:PartC
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• v.8C no.6
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• pp.731-740
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• 2001

Multi-distributed web cluster model expanding conventional cluster system is the cluster system which processes large-scaled work demanded from users with parallel computing method by building a number of system nodes on open network into a single imaginary network. Multi-distributed web cluster model on the structured characteristics exposes internal system nodes by an illegal third party and has a potential that normal job performance is impossible by the intentional prevention and attack in cooperative work among system nodes. This paper presents the mutual authentication protocol of system nodes through key division method for the authentication of system nodes concerned in the registration, requirement and cooperation of service code block of system nodes and collecting the results and then designs SNKDC which controls and divides symmetrical keys of the whole system nodes safely and effectively. SNKDC divides symmetrical keys required for performing the work of system nodes and the system nodes transmit encoded packet based on the key provided. Encryption packet given and taken between system nodes is decoded by a third party or can prevent the outflow of information through false message.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.111-116
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• 2018

This paper introduces the concept of a random universal hash function to amplify security in a quantum key distribution system. It seems to provide security amplification using the relationship between quantum error correction and security. In addition, the approach in terms of security amplification shows that phase error correction offers better security. We explain how the universal hash function enhances security using the BB84 protocol, which is a typical example of QKD(Quantum Key Distribution). Finally, we show that the BB84 protocol using random privacy amplification is safe at higher key rates than Mayers' performance at the same error rate.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1561-1569
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• 2016

As the use of the sensor device increases in IoT environment, the need for device security is becoming more and more important When a sensor device is deployed in IEEE 802.15.4-based LoWPAN, it has to perform the join operation with PAN Coordinator and the binding operation with another device. In the join and binding process, authentication and key distribution of the device are performed using the pre-distributed network key or certificate. However, the network key used in the conventional method has problems that it's role is limited to the group authentication and individual identification is not applied in certificate issuing. In this paper, we propose a secure join and binding protocol in LoWPAN environment that solves the problems of pre-distributed network key.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.5
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• pp.97-104
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• 2001

In this paper, we propose Recoverable Password Based Key Exchange Protocol(RPKEP). RPKEP has user who has password, server which share the secret key information with user, and password recovery agency(PRA) which help to recover the user\`s password. Proposed protocol has some advantages that it is secure against off-line dictionary attack which is considered most important in password based key exchange protocol and suer\`s security is preserved even though user\`s secret information stored in the server is disclosed. By applying Chaum\`s blind signature scheme in the process of password recovery, even the PRA can\`t obtain any information about user\`s password.