• 한국정보과학회논문지:정보통신
• /
• 제29권4호
• /
• pp.333-345
• /
• 2002

컴퓨터와 네트워크의 보급이 일반화되면서 인터넷을 통한 정보 전달이 일상 생활처럼 되고 있다. 또한 인터넷, 무선통신, 그리고 자료교환에 대한 증가로 인해 다른 사용자와 접속하기 위한 방식은 빠르게 변화하고 있다. 그러나 이러한 전자메일에도 많은 문제가 존재한다. 기존의 전자메일은 간단한 방법으로 내용을 열람하거나 변조할 수 있어 중요한 정보나 사생활 노출의 위험에서 벗어날 수 없다. 이러한 데이타에 대한 보안이 기대에 미치지 못하고 있기 때문에 암호학적으로 강력한 전자메일 시스템의 개발이 시급하다. 본 논문에서는 기본적인 정보보호 서비스 외에 기존의 전자메일 시스템에서는 제공되지 않는 배달 증명 및 내용 증명 기능을 제공하고 자바 암호 HPI를 사용하여 안전한 키 교환이 가능하도록 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제16권7호
• /
• pp.2225-2238
• /
• 2022

For advanced healthcare services, a variety of agents should maintain reliable connections with the manager and communicate personal health and medical information. The ISO/IEEE 11073 standards provide convenient interoperability and the optimized exchange protocol (OEP) supports efficient communication for devices. However, the standard does not specify secure communication, and sensitive personal information is easily exposed through attacks. Malicious attacks may lead to the worst results owing to service errors, service suspension, and deliberate delays. All possible attacks on the communication are analyzed in detail, and the damage is specifically identified. In this study, novel secure communication schemes over the 20601 OEP are proposed by introducing an authentication process while maintaining compatibility with existing devices. The agent performs a secure association with the manager for mutual authentication. However, communication with mutual authentication is not completely free from attacks. Message encryption schemes are proposed for concrete security. The authentication process and secure communication schemes between the secure registered agent (SRA) and the secure registered manager (SRM) are implemented and verified. The experimental analysis shows that the complexities of the SRA and SRM are not significantly different from those of the existing agent and manager.

• 한국통신학회논문지
• /
• 제29권1B호
• /
• pp.73-85
• /
• 2004

본 논문에서는 다양한 종류의 서비스 지원이 가능하며, PC, 웹, 모바일 환경을 연동 할 수 있는 새로운 개념의 XML 기반 글로벌 P2P 엔진을 제안하고 이에 대한 설계 및 구현 경험을 소개한다. 제안된 P2P 엔진은 모든 메시지 교환 시 텍스트 기반의 XML을 사용함으로써 웹 연동 및 이기종간 데이터 교환이 가능하며, 다중 수준의 보안레벨과 여러 보안 알고리즘을 적용할 수 있는 기능도 제공한다. 이를 위하여 제안된 시스템은 모든 메시지를 스케줄링, 필터링 하는 Message Dispatcher, 보안 기능을 지원하는 보안 관리자와 전송을 담당하는 전송 관리자를 포함하는 SecureNet Manager, 피어를 검색하여 피어 네트워크 환경을 구성하는 Discovery Manager, 그리고 XML 문서처리 기능을 포함하는 데이터 관리자인 Repository Manager 모듈로 구성되어있다. 본 논문에서 제안된 시스템의 가용성 평가를 위해 커뮤니케이션 서비스인 채팅과 협업 중 공동 저작 도구로서 화이트보드 그리고 파일 공유서비스를 각각 구현하고, 기존의 타 시스템과의 성능 비교 평가를 하였다.

• 전기학회논문지
• /
• 제58권6호
• /
• pp.1215-1222
• /
• 2009

In this paper, a method of designing a controller which ensures the synchronization between the transmission and the reception ends of chaotic secure communication systems with interval time-varying delays is proposed. To increase communication security, the transmitted message is encrypted with the techniques of N-shift cipher and public key. And to reduce the conservatism of the stabilization criterion for error dynamic system obtained from the transmitter and receiver, a new Lyapunov-functional and bounding technique are proposed. Through a numerical example, the effectiveness of the proposed method is shown in the chaotic secure communication system.

• 한국군사과학기술학회지
• /
• 제11권3호
• /
• pp.106-114
• /
• 2008

In this paper we suggest a protocol and an algorithm which connect a secure channel between a server and a client over a TCP layer. To make key exchange time the most quickly, the protocol adopts ECC Diffie Hellman(ECCDH) algorithm. And the protocol does not use Hello message for key exchanges and state changes. We also implement this protocol over an open TCP/IP program and check the secure channel connecting time over the military computer network. The suggested protocol could be practically used on the military computer network without a hardware implementation.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2005년도 춘계학술발표대회
• /
• pp.1083-1086
• /
• 2005

Now these days, many technical concepts and tools have been developed in the cryptographic field. Most digital signature schemes used in practice, such as RSA or DSA, have an important role in information privacy and secure authentication for perfect user. A clearly advantage of such schemes over with security proven relative to such common cryptographic assumptions, is their efficiency: as a result of their relative weak requirements regarding computation, bandwidth and storage, these scheme have so far beaten proven secure schemes in practice. Our aim is to contribute to bridge the gap that exists between the theory and practice of digital signature schemes. In this paper we present a digital signature that ensures information privacy. More precisely, under an appropriate assumption about RSA, the scheme is proven to be existentially forgeable under adaptively chosen message attacks. This mechanism can be applied to smart cards or E-Wallet for maintaining secure authentication for user’s information privacy.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제2권1호
• /
• pp.15-26
• /
• 1998

By "secure", we mean that some well-defined computational assumption can be shown to be sufficient for the scheme not to be existentially forgeable, even under an adaptive chosen message attack. Most, if not all, signature schemes used in practice are based on a computational assumption that is certainly necessary for this kind of security, not known to be sufficient. Since the work of Goldwasser, Micali and Rivest[?], many researches have been done for the secure signature schemes. We modify the Cramer-Damg$\dot{a}$rd scheme to implement a practical and secure signature scheme for smart cards.

• 한국컴퓨터정보학회논문지
• /
• 제21권8호
• /
• pp.29-39
• /
• 2016

Recently, KakaoTalk users seek secure messengers with fears of 'possible' censorship over a mobile messenger. Instead German messenger "Telegram" is gaining popularity in South Korea. Are the known as secure messengers actually secure? In this paper, we evaluate secure mobile messengers in terms of private information protection. We establish the fourteen criteria to evaluate the functionality of messenger apps including communication encryption in transit, the possibility of leakage of decrypted messages via server, an encryption algorithm, a key exchange algorithm, an ephemeral message application, etc. Line, Telegram, Snapchat, WhatsApp, Wickr, Facebook Messenger and KakaoTalk, which have many worldwide and domestic users, are to be targeted. Wickr is ranked at the top of the evaluation, followed by Telegram and Line but KakaoTalk and Snapchat are ranked at the bottom of the evaluation list.

• ETRI Journal
• /
• 제38권5호
• /
• pp.934-940
• /
• 2016

In this paper, secure multicasting with the help of cooperative decode-and-forward relays is considered for the case in which a source securely sends a common message to multiple destinations in the presence of a single eavesdropper. We show that the secrecy rate maximization problem in the secure multicasting scenario under an overall power constraint can be solved using semidefinite programing with semidefinite relaxation and a bisection technique. Further, a suboptimal approach using zero-forcing beamforming and linear programming based power allocation is also proposed. Numerical results illustrate the secrecy rates achieved by the proposed schemes under secure multicasting scenarios.

• ETRI Journal
• /
• 제39권5호
• /
• pp.729-736
• /
• 2017

This work investigates secure cluster-aided multi-hop randomize-and-forward networks. We present a hop-by-hop multi-hop transmission scheme with relay selection, which evaluates for each cluster the relays that can securely receive the message. We propose an analytical model to derive the secure connectivity probability (SCP) of the hop-by-hop transmission scheme. For comparison, we also analyze SCPs of traditional end-to-end transmission schemes with two relay-selection policies. We perform simulations, and our analytical results verify that the proposed hop-by-hop scheme is superior to end-to-end schemes, especially with a large number of hops or high eavesdropper channel quality. Numerical results also show that the proposed hop-by-hop scheme achieves near-optimal performance in terms of the SCP.