• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.9B
• /
• pp.799-807
• /
• 2004

In this paper, a security mechanism for a VoIP system based on SIP was implemented. This was satisfied sec security requirement of RFC 3261. The SIP standard proposes a HTTP digest authentication for user authentication mechanism, TLS for hop-by-hop security and S/MIME for end-to-end security. SRTP draft was implemented for media security. We also analyzed security of proposed SIP standard.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 2001.11a
• /
• pp.313-317
• /
• 2001

본 논문에서는 전자메일에 보안기능과 공중기능을 함께 부여하는 방법에 대해 기술하고 있다. MIME(Multipurpose Internet Mail Extensions)[8]에 대하여 메시지의 무결성과 전자서명 생성 및 검증, 메시지의 암호화 및 복호화, 부인방지 기능을 지원하기 위해S/MIME(Secure/Multipurpose Internet Mail Extensions)[1][2]을 적용하고 또한 문서에 대한 공증기능을 부여하기 위하여 서명 생성 후 오랜 기간 뒤에도 서명과 서명 생성 시 사용된 인증서의 유효성과 폐지여부를 검증 할 수 있도록 제 3 신뢰기관에 의해 발행된 Timestamp[7]를 적용하였다. 그리고 서명된 메일 형식에 receiptRequest[4] 식별자를 사용하여 수신자의 서명을 포함한 signed receipt[4]를 송신자에게 다시 보내게 하여 메일 수신여부를 검증 할 수 있도록 하였다.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.13 no.4
• /
• pp.99-106
• /
• 2017

With the advent of virtual money such as bit coins, interest in the block chain is increasing. Block Chain is a technology that supports Distributed Ledger and is a versatile technology applicable to various fields. Currently, the block chain is conducting research for various applications such as virtual money, trade finance, marketplace, power market, image contents service, and IoT. The technologies that make up the block chain are smart contract, digital signature/hash function and consensus algorithm. And these technologies operate on P2P networks. In this paper, we have studied e-mail system based on the ethereum which is one of the block chain based technologies. Most legacy mail systems use SMTP and the POP3/IMAP protocol to send and receive e-mail, and e-mail use S/MIME to protect the e-mail. However, S/MIME is vulnerable to DDoS attacks because it is configured centrally. And it also does not provide non-repudiation of mail reception. To overcome these weaknesses, we proposed an e-mail system model based on ethereum. The proposed model is able to cope with DDoS attack and forgery prevention by using block chain based technology, and reliable recording and management among block chain participants are provided, so that it is possible to provide a non-repudiation function of e-mail transmission and reception.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.2
• /
• pp.563-572
• /
• 1997

E-mail has been eidely used for unformation delivery as an Inernet serive. As multimedia etchnologies are developed rapidly, most of the recent Unternet infornation servies support multimedia data. E-mail system also needs to suport multimedia nesage. But Internet mail servise using simple maiol transfer protocol(SMTP) speci-fied in RFC 821/822 handles only ASCII text messages repressented with 7-bit code. Each line the message has the length limitation as well. Those are why it cannot satisfy the diverse user'w demands. Multipuepose Unternet mail extensions(MIMZE), which is a modification and supplement of RFC 822,was proposed for supporting transportation of multimedia data.It can solve the limitations of sizes and types in contents of a message. In this study the E-mail system has been designed and implemented according to the MIME standard in order to solve the limitations of transpotation of messages regardless of the message content type. Hypertext markup language(HTML)syntax is applied to the mail system, and so it is possible to display a message consisting of differnt media as an intergrated from for the purpose of better understanding a message. No application program is needed for displaying a message including image data,and convenience for user is considered in the system. The futuer work is to improve the E-mail system so that it may support motion pictures and sound information,Thereby tge perfor multimeda E-mail system providing inergrated user's wiew will be developed.

• Journal of the Korea Society of Computer and Information
• /
• v.17 no.1
• /
• pp.133-140
• /
• 2012

In SIP(Session Initiation Protocol) service, users should send SIP SUBSCRIBE messages to the SIP server to get subscription informations of the other parties, and total amount of SIP messages becomes large in network as refresh messages and notification messages are generated to each SIP subscription. In this paper, a new resource lists architecture using dynamic notification control method has been proposed to solve these problems. In this architecture, service users can control event notification generation rate dynamically from the server according to the operation circumstances, and users can control generation of notification messages during refresh for maintaining SIP session. Furthermore users can also control generation of notification messages according to session connection conditions. A new resource lists MIME type has been designed, and several parameters for dynamic notification message control have been added to the extended SIP message headers. In this system new resource lists MIME type can be used for processing of the event package. Therefore total amount of SIP messages in network can be largely reduced, and load of the resource lists server for processing messages can be reduced also. The performance of the proposed method has been evaluated by experiments.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.5
• /
• pp.1297-1307
• /
• 1997

This paper presents a multimedia mail system which transmit and redeive multimedia mailing messges on Intemet.This mail system is an extension of the exsting e-mail system for multimedia uncluding,text,image,MPEG video,and binary data,The MIME(Multipurpose Intert Mail Extensions)format,which is an extension of REF-822 maill format,is used to reprssent multimedia,and SMTP(Simple Mail Transfer Protocol)is utilized as a mail transport prttocol.The IMAP(Intenet Mail Access Protcol)which privides more functions than the widely used POP(Post Office Protocol)is used as a mailbox retrival protocol.The mail client is complemented on a multimedia PC while the server is implemented on a UNIX system.In the mail system, a mail sending program allows a user to attach binary files such as Postscript files and MPEG compressed video,while a receiving program provides direct interface to application programs to play back received multimedia mail messages.

• Proceedings of the IEEK Conference
• /
• 2000.06c
• /
• pp.129-132
• /
• 2000

It is difficult to find web contents for visual disabilities in spite of rapid growing internet users, infrastructures and advance of computer technology. For the case of usenet newsgroup concerning disabilities, hit rate is even less than E-mail because of lack of accessibility, educational support and economical expense for internet. This paper is addressed to voice usenet newsgroup service by using telephone or web browser for visual disabilities without additional S/W support such as 775, usenet program and installation program, suggests a design method and an implementation example for it. Main features of it are easiness of man machine interface, popularity of access device such as telephone or web browser and independency of particular news server by using NNTP. This system supports general MIME format, is implemented for usenet server of Korean Social Worker's Community and will be implemented for Gomduri InfoNet BBS of Korean Society for Rehabilitation of Persons with Disabilities.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2001.10b
• /
• pp.1111-1114
• /
• 2001

개인자료교환의 방법 중 가장 보편화된 것이 이메일임에도 불구하고, 기존의 웹메일이나 클라이언트 프로그램 등의 UA(UserAgent)는 운영자 임의의 고정적인 인터페이스, 서버접속에 의한 메일 데이터 조작 등으로 활용범위를 좁혀놓았다. 이메일 사용에서 한층 더 나아가 사용자가 보다 효과적으로 이메일 정보를 활용하고 재사용이 가능하도록 하는 시스템을 개발하는 것이 필요하다. 이 논문에서는 이메일정보를 SMTP/MIME표준을 XML표준형식으로 변환/저장하여 사용자가 이메일정보를 다양한 어플리케이션에서 황용하고 재 사용한 수 있도록 하였다. 최근 발전하고 있는 XML기술과 ASP기반의 웹 메일을 통하여 기존에 웹메일 사용자들에게 친숙한 인터페이스를 제공하고, 이메일을 XML로 변환하고 변환된 XML문서를 XML을 이용하여 사용자 취향에 맞게 재구성한 수 있게 하였다. DOM API를 사용하여 변환된 XML파일을 조합하고, DB가 없이 파일로 관리하여 개인사용자가 이메일정보를 소장할 수 있게 하는 시스템을 설계 및 구현하였다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.10c
• /
• pp.402-404
• /
• 2000

웹에 기반한 메일 서비스의 급속한 성장으로 인하여 전자 메일은 인터넷을 이용하는 많은 사용자들의 주요 정보 교환수단이 되었다. 현재의 웹에 기반한 메일 시스템에서 SMTP 프로토콜을 이용하여 메일을 전송할 경우, 전송되는 메시지는 아무런 보안 조치도 취해지지 않은 상태로 전송된다. 그러므로 네트워크에 연결된 내,외부의 침입자에 의하여 정보가 도청될 경우 쉽게 정보가 해석될 수 있는 문제점이 있다. 본 논문에서는 웹 상에서의 메일 서비스로 전자메일을 전송할 경우 데이터부분을 암호화하여 전송함으로써 외부의 침입자에 의해 전송데이터가 가로채지더라도 해독하지 못하도록 하였으며 받은 전자메일에 대하여 원래의 데이터로 복호화 할 수 있는 웹 기반 메일 시스템을 개발하였다. 이를 위하여 보안기능이 강화된 MIME 인코딩 알고리즘을 제안하고 이를 응용한 웹 기반 메일 서비스 및 클라이언트 어플리케이션을 구현하여 실제로 데이터 도청 시 메일 메시지가 보호될 수 있음을 보였다.

• Journal of the Korean Society of Systems Engineering
• /
• v.12 no.2
• /
• pp.47-57
• /
• 2016

As the inventory costs of repairable items in military logistics continue to increase, many studies for optimal inventory level of these items are being carried out in advanced countries, including the US, to reduce these costs. Research on inventory level optimization for repairable items aimed to achieve the availability goal of a system with a MIME(Multi Indenture Multi Echelon) repair policy structure first began with Sherbrooke's METRIC and developed into various types. This research is to analyze and compare recent V-METRIC related studies to search for another variation in this field. This paper mainly looks at how to determine optimum inventory level for each repairable item to achieve a specific availability target within a limited budget, and also how to minimize inventory cost while achieving its availability target by determining optimal inventory level of each repairable item.