• The Journal of the Korea Contents Association
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• v.12 no.1
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• pp.80-90
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• 2012

Medical data sampled through medical sensor nodes can provide services properly only when the data are not lost even during the fault of a home health gateway. The loss of medical data can be minimized if a sensor node, in which it is expected that there are the most saving spaces, is selected after medical sensor nodes tentatively conduct local save or communicate with each other during a fault when data cannot received. Furthermore, efficient saving techniques are necessary since the cycle for sampling information is different according to the type of medical data and a space for distributed saving is different for each apparatus. So, this research suggests an efficient distributed archiving protocol (DAP) for medical data sensor nodes, each of which has a diverse sampling cycle. In order to confirm the usefulness of DAP, DAP between sensor node and gateway was designed and materialized. An experiment was conducted using the materialized program and earned a high level of recovery rate (99.3%) and of accuracy rate, which confirms that sensor nodes can play their role during a temporary fault.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.211-220
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• 2003

본 논문은 신뢰 할 수 없는 네트워크를 통해서도 사용자를 인증하거나 키를 교환하는 것에 적합한 패스워드 인증 프로토콜을 제안한다. 기본 아이디어는 패스워드 검증정보의 램덤성(randomness)을 증가시키기 위하여, 패스워드를 분할한 후 이에 대한 각 패스워드 지식을 확대(amplification)하는 구조로 설계된다. 또한 서버측 파일을 암호화하여 보관함으로써 서버 파일 타협 공격에 강인하도록 구성하였다. 더불어 검증정보 및 서버의 암호화키가 다수의 서버들에게 분산되도록 설계된 방식을 제안한다.

• Journal of Korea Multimedia Society
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• v.7 no.2
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• pp.241-250
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• 2004

In this paper, an application layer protocol between sewer and client is proposed for mobile on-line contents in heterogeneous distributed environments. The proposed protocol guarantees the global state consistency in the distributed environments and controls the flow of communication. The protocol reduces the overhead of handsets for flow control and does not need to maintain state information for contents. CPs, by using the proposed sealable protocol, can easily develop their contents as application processes.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.6
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• pp.19-28
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• 2005

The multiprocessor architecture is a good method to improve the computer system performance. The CC-NUMA provides a single shared space with the physically distributed memories is used widely in the multiprocessor computer system. A CC-NUMA has the full-mapped directory for the shared memory md uses a remote cache memory for tile fast memory access. In this paper, we propose a processing node architecture for a CC-NUMA system and a cache coherency protocol on the physically distributed but logically shared system. We show an implementation result of the system which is adopted the cache coherency protocol.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.23-36
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• 2004

This paper presents a password based authentication and key exchange protocol which can be used for both authenticating users and exchanging session keys for a subsequent secure communication over an untrusted network. Our idea is to increase a randomness of the password verification data, i.e., we split the password, and then amplify the split passwords in the high entropy-structured password verification data. And in order to prevent the verifier-compromised attack, we construct our system such that the password verification data is encrypted with the verifier's key and the private key of verifier used to encrypt it is stored in a secure place like a smart cards. Also we propose the distributed password authentication scheme utilizing many authentication servers in order to prevent the server-compromised attack occurred when only one server is used. Furthermore, the security analysis on the proposed protocol has been presented as a conclusion.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.215-218
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• 2002

패스워드 기반 키분배 프로토콜의 가장 중요한 요구사항 중 하나는 사전공격과 같은 패스워드 추측 공격에 대하여 안전하여야 한다. 그러나 지금까지 제안된 패스워드 추측 공격에 대한 안전성은 비밀 서버를 가정하고 있다. 즉, 검증자 기반 방식이더라도 서버에 저장되어 있는 패스워드 검증자가 비밀리에 보관되어야 한다는 단점이 있다. 본 논문에서는 새로운 방식의 다중 서버를 이용한 패스워드 기반 키분배 방식을 제안한다. 딜리는 사용자에 대한 인증 및 검증자를 각 서버에 전송하는 일을 담당한다. 사용자는 특정 서버와 단독으로 세션키를 교환하지만, 서버는 세션키를 생성하기 위해서는 그룹 내에 있는 모든 서버와 비밀 복원 과정을 거처야만 하는 새로운 방식이다. 사용자와 키분배를 수행하는 특정한 서버는 그룹 내에 있는 다른 서버와 비밀 복원 과정을 거처야만 키분배 과정을 수행할 수 있으므로, 특정 서버의 패스워드 파일이 노출되어 패스워드 검증자가 공격자에게 노출되더라도 비밀 분산 과정을 수행하지 못하는 공격자는 패스워드 추측에 필요한 정보를 획득할 수 없다.