• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.6
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• pp.15-24
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• 2004

Electronic commerce is widely used with the development of information communication technologies in internet using public key certificates. And the study for access control in Web application and DB system is also progressed actively. There are many verification method for PKC(Public Key Certificates), which are CRL, OCSP, SCVP and others. But their certificates verification methods for PKC cannot to be applied to PMI(Privilege Management Infrastructure) which is using AC(Attribute certificates) because of synchronization of PKC and AC. It is because AC has no public key, AC Verifier must get the PKC and verify the validity on PKC and AC. So in this paper we proposed the new AC-based certificate verification model. which provide the synchronization in two certificates(AC and PKC).

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.1
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• pp.99-113
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• 2003

As a research on PKI(Public Key Infrastructure) is being very popular, the study relating to certificate status and path validation is being grown with aim to reduce an overhead of the protocol and to provide an efficient operation. But in spite of a lot of related research there is still almost no protocol that we can use for real-time based client-server environment with large scale like internet banking. In this paper, we shows that the existing standards or protocols are not suitable to be used for such a real-time based client-server environment with large scale, and then proposes an efficient certificate status and path validation system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.6
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• pp.97-106
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• 2003

The important factor in Public-Key Infrastructure is the authentication to correspondent. We receive the digital certificate for authentication between each other, and then we check the existence of validity on the certificate by Certification Revocation List(CRL). But, To use CRL is the scheme used in offline status. So, it is impossible to refer to the latest information and the CRL scheme which is used after downloading is variously unsuitable to getting bigger of the CRL size as time goes on. Therefore, we prefer OCSP(Online Certificate Status Protocol) used in online to CRL used in offline. Consequently, we propose the scheme which provides the request of fast verification in case of requesting the verification on the certificate by owning the same update information to Certificate Registry and distributed OCSP.

• Journal of KIISE:Information Networking
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• v.36 no.6
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• pp.545-551
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• 2009

In this paper, we propose the secure key management framework to connect USN with different network. Although connected USN with different network has no CA (Certificate Authority), it is important to use public key based cryptography system because this network consists of numerous devices. The proposed mechanisms focus on device authentication and public/private key management without existing PKI system of IP network. To solve no CA and certificate problems, the IDC (Identity Based Cryptography) concept is adopted in our proposed mechanism. To verify the possibility of realization, we make an effort to implement the proposed mechanisms to real system. In the test bed, both USN and PLC network are connected to IP network; and proposed mechanisms are implemented to PLC and sensor devices. Through this test using the proposed mechanism, we met the similar performance with symmetric algorithms on key generation and update process. Also, we confirmed possibility of connection between different network and device authentication.

• Proceedings of the Korea Society for Simulation Conference
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• 2004.05a
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• pp.7-12
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• 2004

공개키 기반 구조(PKI; Public Key Infrastructure)에 필수적인 요소인 인증서의 상태 검증에 있어서 인증서 상태 검증 서버인 OCSP (Online Certificate Status Protocol) 서버는 실시간 상태 검증을 제공한다. 그러나, 서버와 클라이언트의 메시지 인증을 위해 전자 서명을 수행해야 하며, 이 때 사용되는 공개 암호 연산 과정의 복잡성은 동시에 많은 클라이언트의 요청이 발생할 경우에 응답 시간을 크게 지연시킨다는 단점을 가지고 있다. 본 논문에서는 이러한 문제를 해결하기 위한 인증서 상태 검증 서버의 시뮬레이션 모델을 DEVS (Discrete Event system Specification) 방법론을 이용하여 설계하였다. 이 모델은 인증서의 상태 검증을 요청하는 영역에 위치하여 해쉬 함수를 적용한 인증을 수행하도록 구성되었으며, 시뮬레이션 결과는 제시한 방법이 인증서 상태 검증 속도를 증대시켜 결과적으로 사용자의 응답 시간이 감소되는 것을 보여준다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.103-109
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• 2008

Many Internet application provide the PKI(public key infrastructure)-based service to provide authentication and message integrity. Several researchers proposed PKI-based p2p network framework. However, in the real world, the use of PKI is not suitable for peer to peer network, because the peer-to-peer network is an open and dynamic network. Moreover, currently there is no nation-to-nation interoperable certificate. In this paper, we designed reliable p2p file sharing application without public key infrastructure. To do this we propose reliable public key distribution mechanism to distribute public key safely without PKI infrastructure for two-tier super-peer architecture. In our system, each peer generates and distributes its public/private key pairs, and the public key is securely distributed without PKI. The proposed mechanism is safe against MITM attack. This mechanism can be applied various P2P applications such as file sharing, IPTV, distributed resource sharing and so on

• The KIPS Transactions:PartC
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• v.12C no.3 s.99
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• pp.317-322
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• 2005

The existing certificate based authentication or identification just verifies whether the owner of private key corresponding to public key of certificate is the DN user set in the user field in the certificate or not, then we cannot find out who is the actual private key owner in a real world. To make up for this weak points, the method to insert the identification number like the resident registration number into the certificate extension field is applied as a technical standard to current domestic PKI system. In this paper, we propose the ECC based integrated identification, identification number checking and key management protocol providing user validation during the login.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.1
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• pp.437-454
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• 2020

According to the privacy regulations of the health insurance portability and accountability act (HIPAA), patients' control over electronic health data is one of the major concern issues. Currently, remote access authorization is considered as the best solution to guarantee the patients' control over their health data. In this paper, a new biometric-based key management scheme is proposed to facilitate remote access authorization anytime and anywhere. First, patients and doctors can use their biometric information to verify the authenticity of communication partners through real-time video communication technology. Second, a safety channel is provided in delivering their access authorization and secret data between patient and doctor. In the designed scheme, the user's public key is authenticated by the corresponding biometric information without the help of public key infrastructure (PKI). Therefore, our proposed scheme does not have the costs of certificate storage, certificate delivery, and certificate revocation. In addition, the implementation time of our proposed system can be significantly reduced.

• Information Systems Review
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• v.3 no.1
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• pp.47-60
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• 2001

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.737-749
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• 2004

Kerberos authenticates clients using symmetric-key cryptography, and supposed to Oust other systems of the realm in distributed network environment. But, authentication and authorization are essential elements for the security. In this paper, we design an efficient and secure authentication/authorization mechanism by introducing the public/private-key and installing the proxy privilege server to Kerberos. In the proposed mechanism, to make a system more secure, the value of the session key is changed everytime using MAC(message authentication code) algorithm with the long-term key for user-authentication and a random number exchanged through the public key. Also, we reduce the number of keys by simplifying authentication steps. Proxy privilege server certifies privilege request of client and issues a privilege attribute certificate. Application server executes privilege request of client which is included a privilege attribute certificate. Also, a privilege attribute certificate is used in delegation. We design an efficient and secure authentication/authorization algorithm with Kerberos.