• Annual Conference of KIPS
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• 2003.05c
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• pp.2149-2152
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• 2003

전자상거래에 관련된 데이터 교환이 인터넷 상에서 쉽고 원활하게 이루어질 수 있도록 하는 어플리케이션에 적합한 언어로 평가받고 있는 XML은 문서의 데이터 포맷 표현을 향상시키는데 중점을 두고 만들어졌기 때문에 문서 변조 및 데이터 삭제 등의 공격에 취약한 문제점을 가지고 있다 이러한 문제점에 대한 해결책으로 XML 전자 서명, XML 암호화 기법, XML 접근 제어와 같은 다양한 해결책이 제시되었지만 XML 암호화로 인한 구조적인 XML 유효성 위반 문제 및 DTD 공격에 대한 해결책 부재 등의 문제점이 해결되지 않고 있다. 본 연구에서는 XML 문서에만 전자서명을 첨부하는 것이 아니라. DTD에 전자 서명을 첨부하는 방법을 제안하였다. 먼저 DTD파일을 끝까지 읽으면서 파싱을 하고 여기서 추출되는 엘리먼트나 속성, 엔티티들을 해시테이블에 저장한다. 파싱이 종료되면 해시 테이블을 읽어 들여서 메시지 다이제스트를 수행한다. 수행 후 이를 개인 키와 합성하여 전자 서명을 생성한다.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.5
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• pp.175-182
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• 2002

The email system is one of the most popular internet applications used to transmit and exchange personal information. However, the pattern of existing email system is fixed, and the system cannot be expanded or re-used. This thesis has proposed the system which can provide the users with better e-mail data which is flexible, re-usable, and expandable XML data on the web-mail. The process of change is as follows: First, make the XML data to have a tree structure using DOM API and then bring the received messages of the users with the CDONTS. Last, transform the received messages into the element and element value. When the e-mail data is transformed t the XML data, 'the data' and 'the presentation' can be distinguished, which enables the users to see messages according to each individual's unique need. With this system, the user can not only convert data to XML, but also can combine the data segments to a form of letter box in order to manage data conveniently and search the data.

• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.75-81
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• 2003

User authentication, including confidentiality, integrity over untrusted networks, is an important part of security for systems that allow remote access. Using human-memorable Password for remote user authentication is not easy due to the low entropy of the password, which constrained by the memory of the user. This paper presents a new password authentication and key agreement protocol suitable for authenticating users and exchanging keys over an insecure channel. The new protocol resists the dictionary attack and offers perfect forward secrecy, which means that revealing the password to an attacher does not help him obtain the session keys of past sessions against future compromises. Additionally user passwords are stored in a form that is not plaintext-equivalent to the password itself, so an attacker who captures the password database cannot use it directly to compromise security and gain immediate access to the server. It does not have to resort to a PKI or trusted third party such as a key server or arbitrator So no keys and certificates stored on the users computer. Further desirable properties are to minimize setup time by keeping the number of flows and the computation time. This is very useful in application which secure password authentication is required such as home banking through web, SSL, SET, IPSEC, telnet, ftp, and user mobile situation.