• 제목/요약/키워드: cyber parties

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Yi등이 제안한 그룹 키 교환 프로토콜의 보안 취약성 및 개선 방법 (Yi et al.'s Group Key Exchange Protocol : A Security Vulnerability and its Remediation)

  • 이영숙;김지연;원동호
    • 한국컴퓨터정보학회논문지
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    • 제17권4호
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    • pp.91-98
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    • 2012
  • 그룹 키 교환 프로토콜은 일련의 그룹을 형성하는 다수의 통신 참여자들이 공개된 통신망을 통해 그룹의 공통 비밀키를 설정하기 위한 목적으로 설계된다. 그룹 지향적인 응용분야들이 인터넷상에서 인기를 더해감에 따라서 이들 응용분야에 안전한 멀티캐스트 채널을 제공하기 위해 많은 그룹 키 교환 프로토콜이 제안되었다. 그동안 제안된 그룹 키 교환 프로토콜 중에 최근 Yi 등이 발표한 패스워드 기반 프로토콜이 있다. 이 프로토콜에서는 각 프로토콜 참가자가 자신의 패스워드를 가지고 있으며 이 패스워드는 신뢰할 수 있는 서버에 등록되어 있다고 가정된다. 패스워드 기반 키 교환에서 가장 근본적인 보안 요구사항은 오프라인 사전 공격에 대한 안전성이라 할 수 있다. 그러나 Yi 등이 제안한 프로토콜은 패스워드에 기반한 프로토콜임에도 불구하고 이 요구사항을 만족하지 못하는 것으로 드러났다. 본 논문에서는 Yi 등의 프로토콜에서 발견되는 이러한 보안 문제점을 지적하고 그 해결책을 제시한다.

영국 해상보험법에서 고지의무 위반에 대한 구제의 대안에 관한 연구 (A Study on Seeking an Alternative Approach to the Remedy for Breach of the Duty of Disclosure in English Marine Insurance Law)

  • 신건훈
    • 무역상무연구
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    • 제24권
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    • pp.25-49
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    • 2004
  • English contract law has traditionally taken the view that it is not the duty of the parties to a contract to give information voluntarily to each other. In English law, one of the principal distinctions between insurance contract law and general contract law is the existence of the duty of disclosure in insurance law. This article is, therefore, designed to analyse the scope or extent of the duty of disclosure and the remedy for breach of the duty in English marine insurance law. The main purpose of this article is also to seek the alternative remedy for the breach. The results of analysis are as following : First, the scope of the duty of disclosure is closely related to the test of materiality and the concept of a hypothetical prudent insurer. The assured is required to disclose only material circumstances subject to MIA 1906, s. 18(1). The test of materiality, which had caused a great deal of debate in English courts over 30 years, was finally settled by the House of Lords in Pan Atlantic and the House of Lords rejected the 'decisive influence' test and the 'increased risk' test, and the decision of the House of Lords is thought to accept the 'mere influence' test in subsequent case by the Court of Appeal. Secondly, an actual insurer is, in order to avoid contract, required to provide proof that he is induced to enter into the contract by reason of the non-disclosure of the assured. But this subjective test of actual inducement is somewhat meaningless in sense that English court takes the test of materiality as a starting point and assumes the presumption of inducement even in case of no clear proof on the inducement. Finally, MIA 1906, s. 18 provides expressly for the remedy of avoidance of the contract for breach of the duty of disclosure. This means rescission or retrospective avoidance of the entire contract, and the remedy is based upon a fairly crude 'all-or-nothing' approach. The remedy of rescission is too draconian from the point of view of the assured, because he can be deprived of all cover despite he is innocent perfectly. An inadvertent breach from an innocent mistake is as fatal as wilful concealment. What is, therefore, needed in English marine insurance law with respect to remedy for the breach is to introduce a more sophisticated or proportionate remedy ascertaining degrees of fault.

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The Effects of the Attractiveness of an Internet Shopping Mall and Flow on Affective Commitment

  • Kang, Sung-Ju;Kim, Jae-Yeong;Park, Young-Kyun
    • 유통과학연구
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    • 제9권4호
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    • pp.29-42
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    • 2011
  • With the many advantages of the internet, online shopping has become one of the fastest growing types of retail businesses. However, internet-based firms are much more firmly required to retain existing customers rather than secure new ones, and to make them revisit the site by strengthening trust and loyalty, thereby improving profits and outrivaling competitors. Commitment is an essential part of successful long-term relationships between buyers and sellers. Although commitments by both parties in an exchange can provide the foundation for the development of relational social norms, disproportionate commitments can lead to opportunism by the less committed partner. Moreover, flow, which is characterized by intense concentration and enjoyment, was found to be significantly linked with exploratory use behavior, which in turn was linked to the extent of computer use. The level of flow was, itself, determined by the individual's sense of being in control, and the level of challenge perceived in maneuvering a website. Website attractiveness goes hand in hand with the attractiveness of an internet shopping mall, and it can be conceptualized as the persuasive effectiveness of a message by the use of familiarity, favor, similarity, etc. It occurs when information receivers try to achieve self-satisfaction when they actually or emotionally identify themselves with an information source. This study investigates the relationship between the perceived system characteristics of an internet shopping mall and the loyalty of online consumers, and it examines how perceived website attractiveness and flow play mediating roles between the perceived system characteristics of an internet shopping mall and the affective commitment in the context of a clothes internet shopping mall. For these purposes, a structural model comprising several variables was developed. That model was tested with an analysis of moment structure (AMOS) using data from respondents who had purchased clothing through the internet during the past three months. In this model, the perceived system characteristics of an internet shopping mall, such as familiarity, reputation, uniqueness, positive emotions, self-efficacy, and interactivity, were proposed to affect the website's attractiveness and flow, and lead to a higher affective commitment over time. Thus, the perceived website attractiveness and flow were proposed as core mediating variables between perceived system characteristics and affective commitment. The results of a reliability test using Cronbach's Alpha, and a confirmatory factor analysis warranted using unidimensionality for the measures for each construct. In addition, the nomological validity of the measures was warranted from the results of a correlation analysis. The results of empirical analyses indicated that systematic attributes resulting in website attractiveness and user's characteristics, thereby triggering customers' flow, play a crucial role in inducing customers' affective commitment, and a user's characteristics are twice as important as systematic attributes in this study. Moreover, familiarity, reputation, and uniqueness all have a significant effect on website attractiveness, and the research showed that uniqueness took the first place, and that familiarity and reputation followed in order of magnitude. The fact that reputation was not the most important factor that affects the attractiveness of an internet shopping mall, with uniqueness or familiarity having a greater impact, suggests much deeper implications. Finally, positive emotion, self-efficacy, and interactivity all have a significant effect on customers' flow. In particular, the fact that positive emotion, compared to self-efficacy or interactivity, has much more impact on flow is very suggestive.

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텔레그램 메신저 기반의 오디오 스테가노그래피 봇넷 구축 (Construction of an Audio Steganography Botnet Based on Telegram Messenger)

  • 전진;조영호
    • 인터넷정보학회논문지
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    • 제23권5호
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    • pp.127-134
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    • 2022
  • 스테가노그래피(Steganography)란 다양한 멀티미디어 파일에 비밀 메시지를 숨기는 은닉 기법을 말하며, 스테가노그래피 기반의 은닉 통신을 할 때 송신자와 수신자 외에 제 3자는 통신 메시지에 은닉 정보의 존재 여부를 식별하기 매우 어렵다는 장점으로 인해 사이버범죄와 공격에 많이 악용되고 있다. 봇넷은 일반적으로 봇마스터, 봇, 그리고 C&C(Command & Control) 서버로 구성되고 봇마스터에 의해 통제되는 네트워크이며, 중앙집중형, 분산형(P2P), 그리고 하이브리드형 등 다양한 구조를 갖고 있다. 최근에는 봇넷의 은닉성을 강화하기 위해 SNS 플랫폼을 C&C 서버 대신 활용하고 스테가노그래피 기법을 적용하여 C&C 통신을 수행하는 스테고 봇넷(Stego Botnet)에 대한 연구가 활발히 진행되고 있으나, 이미지 또는 비디오 매체 위주의 스테고 봇넷 기법들이 연구되어왔다. 한편, SNS 상에서는 다양한 음원 및 녹음 파일 등과 같은 오디오 파일 역시 활발히 공유되고 있어 오디오 스테가노그래피 기반의 스테고 봇넷에 대한 연구가 필요하다. 따라서, 본 연구에서는 텔레그램 메신저(Telegram Messenger)에서 오디오 파일을 커버 매체로 하고 스테기노그래피 기법을 활용하여 C&C 은닉 통신을 수행하는 스테고 봇넷을 설계 및 구축하고 실험을 통해 파일 형식별, 툴별 은닉용량에 대해 비교 분석한 결과를 제시한다.