• Journal of Internet Computing and Services
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• v.15 no.2
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• pp.49-58
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• 2014

With the fast development of internet, cloud computing has become the most demanded technology used all over the world. Cloud computing facilitates its consumers by providing virtual resources via internet. One of the prominent services offered in cloud computing is cloud storage. The rapid growth of cloud computing also increases severe security concerns to cloud storage. In this paper, we propose a scheme which allows users not only securely store and access data in the cloud, but also share data with multiple users in a secured way via unsecured internet. We use ECC for cryptography and authentication operation which makes the scheme work in a more efficient way.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.495-498
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• 2014

최근 스마트폰을 이용한 인터넷 사용이 증가하면서 카페나 영화관과 같은 공공장소에 많은 Access Point(AP)들이 설치되어 있다. 하지만 이러한 AP 대부분이 외부 공격에 무방비하게 노출되어 위험성이 대두되고 있다. 대표적인 공격으로 사용자와 AP간 통신에 끼어들어 데이터를 도청하거나 위 변조하는 Man-In-The-Middle(MITM) 공격이 있다. MITM 공격에 대한 대응책으로 통신간 암호화가 있지만, 모든 통신에 암호화를 적용하는 것은 많은 비용이 발생하기 때문에 현실적으로 불가능하다. 실제로 구글 플레이스토어에 등록된 100개의 무료 인기 어플리케이션 중 모든 메시지에 암호화 통신을 사용하는 어플리케이션은 없으며, 부분적으로 사용하는 어플리케이션은 43개임을 확인하였다. 본 논문에서는 앞서 설명한것과 같이 통신간 암호화를 하지 않는 어플리케이션을 MITM 공격으로부터 보호하기 위한 메시지 인증 기반 무결성 검증 방법을 제안하여 안전한 어플리케이션-서버 통신 모델 개발에 기틀을 마련한다.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.675-682
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• 2013

This paper tries to solve the problems which previous methods have the model using smart card for protecting digital contents. This study provides a contents distribution model to protect the rights of author, distributor, and user as well as user's information by using technologies such as cryptography, DRM(Digital Right Management), access control, etc. The proposed system is evaluated as the most safety model compared with previous methods because it not only solves the problems which the previous methods have, but also protects four type of risks such as use of contents which other mobile devices download, the attack on the key to decode the message, the attack on leaking the contents, and the internal attack such as an illegal reproduction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.7
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• pp.545-552
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• 1990

This paper is concerned with the file protection in the file transfer systems. In the existing file transfer systems, passwords are used in the protection but do not provide any data protection and can only provide some protection against unauthorized access. Even provided with this protection, we cannot be free form computer hackers. In order to achieve higher standards of protection for our privacy (protection for data themselves, authentication of senders...) analternative technical system should be developed in using of pulic key cryptography by choosing the public key method (RSA public key) in the file transfer. A new system suggested in the paper can achieve some higher standards of protection for our privacy. We a result thie system will be easily applied to various document handling systems as in the data base.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.1
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• pp.53-59
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• 2019

As the number of harmful sites increases, many social problems are occurring. Therefore, in order to solve this problem, the government is carrying out activities to block access to web sites to harmful sites based on the law. However, due to the change from HTTP to HTTPS protocol, it has become difficult to block the harmful sites in the existing method. In the existing HTTP protocol, a method of blocking the site corresponding to the harmful site domain list by utilizing the DNS information was used. However, due to the generalization of HTTPS, it is difficult to block the harmful sites in the existing method. Therefore, the ISP uses the method of blocking the website using the SNI field in the TLS (Transport Layer Security) Handshake protocol used for HTTPS. However, since the method using SNI field raises the concern of monitoring Internet users or exposing information about connected sites, in this paper, we proposed method which can support anonymity to Internet users while blocking harmful sites. The suggested method also can support integrity and source authentication to the transmitted data.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.258-261
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• 2006

네트워크 기술이 발전함에 따라 유/무선 네트워크가 통합되기 시작하였고, 궁극적으로 언제/어디서나 컴퓨터를 사용한 수 있는 유비쿼터스 컴퓨팅 시대가 도래 할 것으로 예상된다. 최근에는 공공장소에서 고속의 무선 인터넷 접속에 대한 욕구가 커지면서 무선랜에 대한 관심이 많아지고 있다. 무선랜 환경에서 중요한 보안문제 중 하나는 승인된 사용자에게만 접속을 허용하는 것이다. 특히, 유선 네트워크와 다르게 무선 네트워크 환경에서는 Access Point(AP)가 설치되어 있는 곳이면 누구나 깁게 AP를 통해 네트워크를 이용할 수 있기 때문에 접속에 관한 보안의 중요성이 강조되고 있다. 본 논문에서는 무선랜 환경에서 안전하게 사용자를 인증하고 서비스를 제공하기 위해 지문을 이용한 사용자 인증 프로토콜을 제안한다.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.37-44
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• 2010

The mobility is one of the most important factor for mobile IPTV. However, mobility is highly vulnerable to eavesdropping and unauthorized access. Generally mobility of mobile services is based on handover techniques. But we showed that mobile IPTV must use other techniques to confirm mobility. In this paper, we analyzed security of wibro mobile IPTV from the viewpoint of mobility. We considered DCAS host must include new addresses of mobile devices. We analyzed total number of authentication for the proposed method. So we showed that proposed method was more efficient than wibro-mobile IPTV. We compared the security of our proposal to the security requirements of TTA.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10c
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• pp.540-543
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• 2006

DTV는 방송 서비스 운영에 가입자 개념을 추가하여 무료방송 외에 정당한 수신료를 지불하는 사람만이 프로그램을 시청할 수 있도록 하며, 그러한 수익을 이용하여 보다 양질의 서비스를 제공할 수 있게 되었다. 가입자간의 구분을 가능하게 해주기 위한 방법이 제한수신시스템(CAS: Conditional Access System)이다. IPTV는 웹 브라우저를 기반으로 동작하며, 방송 콘텐츠라는 기본 TV기능에서 벗어나 T-commerce, E-commerce 등의 다른 도메인으로 사용자의 요구에 따라 자유롭게 이동하며 사용자인증이 요구되기 때문에 기존의 제한수신시스템으로는 그 기능을 다 하기 힘들어졌다. Single-Sign-On은 사용자가 단한번의 인증을 통하여 추가적으로 인증할 필요가 있는 다른 서비스로의 자동적인 인증을 제공한다. 다수의 사용자가 다수의 서비스를 제공받기를 원하는 IPTV환경에서는 단순한 사용자 인증과 접근제어의 기능을 가진 제한수신시스템과 빈번한 사용자인증의 번거로움을 해결할 수 있는 편의성을 제공하는 SSO의 융합은 필연적이라 할 수 있다. 그러므로 Single-Sign-On은 사용자의 요구에 따라 이동하기 쉬운 IPTV 환경에 매우 적합하다. 이 논문에서는 제한수신시스템, SSO, IPTV에 대해 설명하고 제한수신시스템과 SSO의 기능을 통합하여 IPTV환경에 적합한 새로운 인증방안을 제안한다.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.743-747
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• 2009

We designed and implemented an automatic update system of 네비게이션 contents. Currently car users are updating map contents of their 네비게이션 system by using SD memory card. In the implemented system, map contents are downloaded via WI-FI internet access while served in a gas station. To prevent free rider at gas stations, we adopted authentication mechanism based on MAC address.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.975-983
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• 1998

In these days, information communication systems are based on both open distributed computing technologies and object-oriented techniques like inheritance, encapsulation and object reuse to support various system configuration and application. As information systems are interconnected through unsecure networks, the need for the secure information exchange is more critical than before. In this paper, we have designed and implemented a transparent CORBA-basce Security infrastructure with authentication, security context association, access control and security information management to support a secure applications in distributed object environment. SESAME Ver. 4 was adopted as an external security service to manage user privilege attributes and to distribute keys for data encryption, decryption and integrity. Using filter and transformer with an interface to Object Request Broker, it provides a transparent security service to applications. The filter objects are special classes that allow additional parameters to be inserted into messages before they are sent and removed just after they are received. The transformer objects are special classes that allow direct access to the byte stream of every messages for encryption and decryption before it is sent and just after it is received. This study is to implement the access control interceptor(ACI) and the secure invocation interceptor(SII) of secure ORB defined in CORBA using filter and transformer.