• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.504-510
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• 2003

안전한 멀티캐스트란 동적으로 그룹 멤버가 변하는 환경에서는 현재의 그룹 멤버만 데이터를 얻을 수 있도록 멀티캐스트하는 방법을 말한다. 이를 위해 그룹 멤버간에 그룹키를 공유하며, 이 키로 암호화하여 데이터를 멀티캐스트한다. 전방향 안전성(forward secrecy)과 후방향 안전성(backward secrecy)을 제공하기 위해 멤버가 가입하고 탈퇴할 때마다 공유키를 변경해야 한다. 이 때 확장성을 위해 그룹키의 변경이 그룹 전체에 미치는 영향은 최소화되어야 한다. 지금까지의 연구는 확장성 문제를 해결하기 위해 플랫한 그룹키 공유 구조에서 계층 구조로 변화해 왔으며, 그룹의 파티션을 용이하게 하고 중앙집중 방식의 문제를 극복하기 위해 중앙 키 서버를 사용하지 않고 그룹 멤버가 생성한 값을 계산을 통하여 그룹키를 생성하는 프로토콜로 변화해 오고 있다. 하지만 지금까지 제안된 안전한 멀티캐스트 방식은 멤버의 가입은 확장성을 갖추고 있지만 멤버의 탈퇴는 그렇지 못하며, 성능 측면에서 많은 개선이 있었지만 실제 응용에 사용되기에는 아직도 연산 측면에서 적절하지 못하다. 이 때문에 이 논문에서는 실제 응용에서 안전한 멀티캐스트를 효율적으로 사용할 수 있도록 그룹키 분배를 위한 중앙 서버를 사용하지 않는 환경에서 가입과 탈퇴가 일어날 때마다 개별적으로 처리하지 않고 일괄 처리하는 여러 알고리즘을 제안하고 그 성능을 분석한다.

• Convergence Security Journal
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• v.21 no.3
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• pp.3-11
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• 2021

Most of the internet security protocols rely on classical algorithms based on the mathematical complexity of the integer factorization problem, which becomes vulnerable to a quantum computer. Recent progresses of quantum computing technologies have highlighted the need for applying quantum key distribution (QKD) on existing network protocols. We report the development and integration of a plug & play QKD device with a commercial IPSec device by replacing the session keys used in IPSec protocol with the quantum ones. We expect that this work paves the way for enhancing security of the star-type networks by implementing QKD with the end-to-end IP communication.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.5
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• pp.111-124
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• 2010

AMI (Advanced Metering Infrastructure) is a core infrastructure of Smart Grid, and is promoting in various country. Wireless network is considered for cost savings and operational efficiencies in AMI. But various security problems are expected in wireless networks of AMI, so we should solve these problems. In this paper, we suggest a wireless network of AMI by using Binary CDMA and security countermeasures of AMI wireless network. Proposed security architecture is using BSIM (Binary Subscriber Identity Module) to perform user authentication and key agreement for the encryption and decryption over radio network to reduce security threats.

• Annual Conference of KIPS
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• 2011.11a
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• pp.774-777
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• 2011

산업제어시스템(ICS: Industrial Control System)은 전력 생산, 댐 운영, 가스 생산, 수자원 관리, 원자력 발전 설비 등의 운영을 제어하고 관리하는 시스템이다. 대부분의 국가 기반 시설은 이러한 제어시스템에 의해 관리되고 있으며, 정보통신 기술이 발전하면서 업무망과 제어시스템망을 나누워 구축하며 점차 개방화되어 가고 있다. 이로 인한 IT측면에서 발생하는 사이버 공격이 비교적 폐쇄적인 제어 시스템 망으로 언제든지 이루어질 수 있으며, 실제 국내에서 독립적인 네트워크를 사용함에도 불구하고 금융권의 전산망이 마비되는 사태가 발생하였다. 또한 국외에서는 이란의 원자력 발전소 제어 시스템을 목적으로 하는 'Stuxnet' 악성코드로 인해 발전소 운용이 중단돼는 사례도 발생하였다. 산업용 시스템의 목적과 특성상 사이버 침해사고 발생 시 국가적 손실 및 생명에도 위협을 받을 수 있다. 본 논문은 과거에 보안을 고려하지 않고 구축되었던 제어시스템을 사이버 침해로부터 보호하기 위해 제어시스템을 위한 통신 프로토콜 암호화 및 화이트리스트보안 기술을 이용한 시스템 적용 방안을 소개하며, 네트워크 접속시 인가된 산업용 PC의 안전성을 평가하기 위해 요구되는 보안 플렛폼 설계를 한다.

• Annual Conference of KIPS
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• 2007.11a
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• pp.1210-1213
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• 2007

WiBro는 무선랜과 3G 이동통신의 장점을 결합한 휴대 인터넷 기술로 최근 국내에서 상용화 되었다. WiBro의 장점인 이동성과 고속 무선 통신에 기인하여, 향후 지속적인 발전이 기대된다. 이러한 WiBro의 확산에 따라 개인 사용자에 대한 보안문제가 최근 크게 부각되고 있다. 현재 Wibro는 3G 이동통신 및 무선랜과 효율적인 연동을 위해 EAP-AKA 인증기법을 사용하고 있다. 하지만 EAP-AKA는 단말이 기지국을 인증하지 못하는 치명적인 취약점이 있다. 따라서 공격자는 임의로 rogue BS를 설치할 수 있고, 정상 사용자의 데이터를 이종 네트워크로 보내는 Redirection Attack을 시도할 수 있다. Redirection Attack은 전송 속도 저하, Denial-of-Service (DoS) 을 초래하며, 데이터가 redirection 되는 이종 네트워크에 따라 암호화된 데이터가 노출될 수 있다. 본 논문에서는 EAP-AKA와 Redirection Attack에 대해 분석하고, 그 해결책을 제시한다. 논문은 1) 프로토콜을 일부 수정하여 공격을 막는 방법과 2) traffic 분석을 통한 공격 탐지 방식을 다루고 있으며, 이러한 두 가지 방법을 통해 Redirection Attack에 대한 취약점을 근본적으로 제거할 수 있다.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.377-386
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• 2003

In this paper, we present an application layer protocol to support secure wireless Internet services, called Application Layer Security(ALS). The drawbacks of the two traditional approaches to secure wireless applications motivated the development of ALS. One is that in the conventional application-specific security protocol such as Secure HyperText Transfer Protocol(S-HTTP), security mechanism is included in the application itself. This gives a disadvantage that the security services are available only to that particular application. The other is that a separate protocol layer is inserted between the application and transport layers, as in the Secure Sockets Layer(SSL)/Transport Layer Security(TLS). In this case, all channel data are encrypted regardless of the specific application's requirements, resulting in much waste of network resources. To overcome these problems, ALS is proposed to be implemented on top of HTTP so that it is independent of the various transport layer protocols, and provides a common security interface with security applications so that it greatly improves the portability of security applications. In addition, since ALS takes advantages of well-known TLS mechanism, it eliminates the danger of malicious attack and provides applications with various security services such as authentication, confidentiality integrity and digital signature, and partial encryption. We conclude this paper with an example of applying ALS to the solution of end-to-end security in a present commercial wireless protocol stack, Wireless Application Protocol.

• Journal of Internet Computing and Services
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• v.13 no.2
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• pp.59-71
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• 2012

PKI-based public key scheme is outstanding in terms of authenticity and privacy. Nevertheless its application brings big burden due to the certificate/key management. It is difficult to apply it to limited computing devices in WSN because of its high encryption complexity. The Bilinear Pairing emerged from the original IBE to eliminate the certificate, is a future significant cryptosystem as based on the DDH(Decisional DH) algorithm which is significant in terms of computation and secure enough for authentication, as well as secure and faster. The practical EC Weil Pairing presents that its encryption algorithm is simple and it satisfies IND/NM security constraints against CCA. The Random Oracle Model based IBE PKG is appropriate to the structure of our target system with one secret file server in the operational perspective. Our work proposes modification of the Weil Pairing as proper to the closed network for secret file distribution[2]. First we proposed the improved one computing both encryption and message/user authentication as fast as O(DES) level, in which our scheme satisfies privacy, authenticity and integrity. Secondly as using the public key ID as effective as PKI, our improved IBE variant reduces the key exposure risk.

• The Journal of the Korea Contents Association
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• v.4 no.1
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• pp.55-66
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• 2004

Recently, as the personal computers are supplied rapidly, they formed the nucleus of the computer system. But, because of the easiness that anyone uses them to go near easily, it is the fact that the security of personal computer is weakness. So, in the paper, 1 propose the technical method that minimizes the loss and leakage of important data. This paper implemented a crypto system for security of data file on personal computer and assistance storage medium. The way of encryption/decryption is applied by complexity method which mixed Diffie-Hellman key exchange protocol, a typical RC4(Rivest Cipher version 4) algorithm of stream cipher and a typical MD5(Message Digest version 5) of Hash Function. For valuation implemented crypto system, three criteria is presented, which are crypto complexity, processing time and pattern matching. And according to analysis the three criteria the crypto system is verified the security, efficiency and usefulness. The crypto system is programmed with Visual C++ language of Microsoft. And so, as this is software system, we shall have a technical security system at a minimum cost for all personal computer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.746-754
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• 2016

Smart healthcare systems, a convergent industry based on information and communications technologies (ICT), has emerged from personal health management to remote medical treatment as a distinguished industry. The smart healthcare environment provides technology to deliver vital information, such as pulse rate, body temperature, health status, and so on, from wearable devices to the hospital network where the physician is located. However, since it deals with the patient's personal medical information, there is a security issue for personal information management, and the system may be vulnerable to cyber-attacks in wireless networks. Therefore, this study focuses on a key-development and device-management system to generate keys in the smart environment to safely manage devices. The protocol is designed to provide safe communications with the generated key and to manage the devices, as well as the generated key. The security level is analyzed against attack methods that may occur in a healthcare environment, and it was compared with existing key methods and coding capabilities. In the performance evaluation, we analyze the security against attacks occurring in a smart healthcare environment, and the security and efficiency of the existing key encryption method, and we confirmed an improvement of about 15%, compared to the existing cipher systems.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.127-136
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• 2013

The study of the compatibility of EPUB DRM, granted by the Korea Copyright Commission, as a CT R & D project (Project Title: The Development of the standard reference software technology for International Standard EPUB-based eBook DRM) developed standards such as profile standards for encryption digital signature and authentication certificates and standards for technical terms of rights information. In 2012, these four standards have been established as the Korean Industrial Standards under the names of 'Encryption specification for EPUB DRM,' 'the Digital signature specification for EPUB DRM,' 'the Certificate specification for EPUB DRM,' and 'Definitions of Right Terms for EPUB DRM' through the ODPF(Open Digital Standardization Forum) and the TTA(Telecommunications Technology Association). The research project also proposed standards of ebook DRM license protocols in order for the four standards to practically apply to ebook DRM compatibility. It is necessary for technology standards to require a compatibility standard test process for testing whether implementations which were developed on the basis of the standard specification, comply with standards. This study suggests an automated compatible standard test method and a test model under the ebook DRM standard technical specification.