• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.6A
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• pp.129-137
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• 2008

As the use of the internet increases, the distribution of spam mail has also vastly increased. The email's main use was for the exchange of information, however, currently it is being more frequently used for advertisement and malware distribution. This is a serious problem because it consumes a large amount of the limited internet resources. Furthermore, an extensive amount of computer, network and human resources are consumed to prevent it. As a result much research is being done to prevent and filter spam. Currently, research is being done on readable sentences which do not use proper grammar. This type of spam can not be classified by previous vocabulary analysis or document classification methods. This paper proposes a method to filter spam by using the subject of the mail and N-GRAM for indexing and Bayesian, SVM algorithms for classification.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.2
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• pp.107-122
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• 1997

Most of the currently used electronic mail system has the threat of security such as illegal leak of message, forgery, uncertain identity, denial of sending and receiving, and so forth. The security for this system is not satisfied yet, thus we explore these problems. In this thesis, we implement the security services for internet mail system which cover the weakness for traditional mail system. This system provides not only security services which PEM and PGP provides (i.e message confidentiality, message integrity, originator authentication, non-repudiation of origin), but also message replay prevention. and non-denial of recipient using certification of contents. In addition, this system increases security of the digital signature by signing with signature block formatting on the creation of it. And it increases security of the digital enveloping by encrypting with encryption block formatting of message encryption key.

• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.437-444
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• 2006

A chaos cipher system that focuses on the stream cipher system has a demerit that the longer the text is, the slower the speed of the encryption and description and the transmission and reception. On this study, we designed the cipher web mail system showing much better capabilities than the existing web mail system as the text is longer. In the embodiment of the cipher web mail system, we developed the key stream, the encryption and description of the text and the inside and outside mail viewer and so on. After the efficiency test, it was valued high in the respect of the speed of the encryption and description and the transmission and reception. And it made up for the defect of the stream cipher system. We expect that we can use it through the persistent applied study in the server system security, the file security, the security of the internet information, the protection of the e-commerce system information and other fields based on the cipher technique as the wide use cipher system that can replace the block cipher system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.324-327
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• 2000

There are developing the World Wide Web systems for their information sharing among certain closed user group. These systems are required five common functions as follows. First, they have to support the web service for Internet users to access easily. Second, Hey have to support the authorization service to confirm the allowed users. Third, they have to support the database service to manage the sharing information among users. Fourth, they have to support the bulletin board service for closed users to discuss. Fifth, they have to support the e-mail service to send e-mail to the certain user subset and mail archive service to save and manage the previous mail information. In this paper, we described the detail function and processing procedure of our implemente system under LINUX operating system. In addition, we described problems occurring in implementation and their solutions.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.135-136
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• 2011

The more VoIP service is widely used, the more VoIP spam becomes threatened. Both VoIP spam violates the user's privacy and VoIP spam can cause money trouble. Therefore, it is important to reduce the VoIP spam but it is not easy to adopt some useful techniques to counter e-mail spam due to VoIP characteristics. We propose a technique using VoIP-RBL for countering SIP-based VoIP spam.

• Journal of the Korea Safety Management & Science
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• v.4 no.1
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• pp.57-68
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• 2002

As Internet spreads rapidly, the industrial structure is changing to a new paradigm. The previous EDI system was asked to change and WEB EDI, E-Mail EDI, FTP EDI etc. which are based on the internet appeared. These days the XML/EDI which has XML document appeared. The XML/EDI consider advantages and disadvantages of VAN/EDI and EDI which based on the internet. Also, EDI system has to assure a safe exchange between sender and receiver. But, the internet has security problems because it uses a open TCP/IP protocol. Although there are many methods for security, it is being studied with XML concept. On this paper, we will suppose the XML/EDI system model with XML Signature, and build a procedure of electronic signature and delivery of document between sender and receiver.

• Annual Conference of KIPS
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• 2013.11a
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• pp.800-803
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• 2013

이메일을 기반으로 좀비PC 및 봇넷그룹을 탐지하는 알고리즘은 기존에 연구가 되었으나, 기존의 검증방식은 가상의 메일계정을 이용해 스팸메일을 수집하는 스팸트랩 시스템에서 추출한 이메일을 대상으로 하였다. 본 논문에서는 상용환경의 이메일을 대상으로 좀비PC를 탐지하고, 좀비PC를 이용한 추가 사이버 공격을 예방하기 위해 기존의 알고리즘을 보완하고, 이에 대한 좀비PC 탐지결과를 분석한다. 이를 통해, 주요 포탈 및 기업의 메일서버에서 수신하는 이메일을 대상으로 좀비IP를 탐지하여, 스팸메일을 차단하고 ISP와 연계하여 실제 조치를 유도할 수 있을 것으로 기대한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.223-229
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• 2017

This paper proposes the Global Clipboard System and presents a preliminary study on it. The clipboard is a temporary storage used to copy and paste some contents between application programs in Windows Operating System. The proposed Global Clipboard is a contents delivery system that extends the concept of the existing local clipboard to Internet. The Global Clipboard System operates in two steps. An application user can upload selected contents to the Global Clipboard by typing consecutive keys of Ctrl-C and Ctrl-Shift-C easily. And other users can download and utilize the contents from the Global Clipboard by typing Ctrl-Shift-V and Ctrl-V keys consecutively. The proposed Global Clipboard can deal almost data like simple texts, screen capture images, files, and directories. In this paper, we developed a global clipboard server, a Windows application, and an Android application. We have conducted experiments about functions of the Global Clipboard and also compared delay times between 4 applications such as e-mail, Kakao, Google Drive, and the Global Clipboard. The results of the evaluation show that the time delay spending in sending and receiving contents is shortest when the Global Clipboard is used.

• Journal of Korea Society of Industrial Information Systems
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• v.1 no.1
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• pp.236-265
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• 1996

It is quite a necessity for the small and medium corporations(Abbre : SMC) to have information technology in order to survive in ever changing global business environment . Especially recently, the importance and uses of Internet have greatly increased by SMCs facing changing environment. This thesis aims to propose various application alternatives of Internet through the analysis of the Internet uses by SMCs. For the analysis, questionaires were distributed nationally to 126 small and medium corporate entities, and 64 out of 82 retrived questionaires have been used for the analysis. The analysis revealed several notable points related with Internet applications by SMCs that , although SMCs strongly feel the need for the use of Internet. -the level of recognition for the existence of the Internet was relatively low -the time used was also at low level -the job which uses Internet was mainly marketing related -and the fields applied were concentrated in those of search and e-mail. The benefits which are derived from the use of Internet include swift provision of technological information to SMCs ,improvement of active interchanges of information through the whole relate networks, strengthened promotion of products made by Internet to promote smooth communications (among related divisions or personnels), to automate work systems , and to systemizestrategic management planning process etc. Consequently, it is expected that, althgough the level of application of Internet is quite low, Internet can be served as a source of information technology and futher as a weapon to better combat strong competition through various supports at government level, since small and medium corporations feel its strong need for Internet.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.3
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• pp.291-301
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• 2002

In this paper, we introduce a mathematical model to analyze pricing/quality and service mix strategies for Internet Portal site. This model includes utilities and costs of each participants, i.e., user, third party provider, and portal sites. Especially, we consider portal sites that initiate their businesses by providing free services like free e-mail service or search service and providing several charged services. As the results, we can find that Portal sites should make the target of customers and focus them to maximize their profit. Portal sites should pay their marketing effort not for all customers but pertinent portions of customers. And Portal sites should make more efforts to efficiently develop and provision their services.