Yuko Murayama

Advances in Information and Computer Security

Software and Multimedia Security.- A Note on the (Im)possibility of Using Obfuscators to Transform Private-Key Encryption into Public-Key Encryption.- Design Issues of an Isolated Sandbox Used to Analyze Malwares.- Collusion-Resistant Fingerprinting Scheme Based on the CDMA-Technique.- Public-Key Cryptography (1).- Reduction Optimal Trinomials for Efficient Software Implementation of the ? T Pairing.- Experiments on the Linear Algebra Step in the Number Field Sieve.- Batch Pairing Delegation.- Botnet Traffic Detection Techniques by C&C Session Classification Using SVM.- A Global Authentication Scheme for Mobile Ad-Hoc Networks.- An Efficient Pre-authentication Scheme for IEEE 802.11-Based Vehicular Networks.- Intrusion Detection and Identification System Using Data Mining and Forensic Techniques.- Run-Time Randomization to Mitigate Tampering.- Privacy-Preserving Eigentaste-Based Collaborative Filtering.- Secure and Private Incentive-Based Advertisement Dissemination in Mobile Ad Hoc Networks.- Verifiable Internet Voting Solving Secure Platform Problem.- Enforcement of Integrated Security Policy in Trusted Operating Systems.- Salvia: A Privacy-Aware Operating System for Prevention of Data Leakage.- InfoCage: A Development and Evaluation of Confidential File Lifetime Monitoring Technology by Analyzing Events from File Systems and GUIs.- Public-Key Cryptography (2).- Accredited Symmetrically Private Information Retrieval.- Generic Certificateless Encryption in the Standard Model.- On Security Models and Compilers for Group Key Exchange Protocols.- Processing Multi-parameter Attacktrees with Estimated Parameter Values.- Practical Security Analysis of E-Voting Systems.- Fine-Grained Sticky Provenance Architecture for Office Documents.- Secure Anonymous Communications with Practical Anonymity Revocation Scheme.- GAS: Overloading a File Sharing Network as an Anonymizing System.- A Composite Privacy Protection Model.- Nominative Signature from Ring Signature.- Anonymous Authentication Protocols with Credit-Based Chargeability and Fair Privacy for Mobile Communications.- How to Find Many Collisions of 3-Pass HAVAL.- A Secure Threshold Anonymous Password-Authenticated Key Exchange Protocol.

User's Action and Decision Making of Retweet Messages towards Reducing Misinformation Spread during Disaster

The online social media such as Facebook, Twitter and YouTube has been used extensively during disaster and emergency situation. Despite the advantages offered by these services on supplying information in vague situation by citizen, we raised the issue of spreading misinformation on Twitter by using retweets. Accordingly, in this study, we conduct a user survey (n = 133) to investigate what is the user’s action towards spread message in Twitter, and why user decide to perform retweet on the spread message. As the result of the factor analyses, we extracted 3 factors on user’s action towards spread message which are: 1) Desire to spread the retweet messages as it is considered important, 2) Mark the retweet messages as favorite using Twitter “Favorite” function, and 3) Search for further information about the content of the retweet messages. Then, we further analyze why user decides to perform retweet. The results reveal that user has desire to spread the message which they think is important and the reason why they retweet it is because of the need to retweet, interesting tweet content and the tweet user. The results presented in this paper provide an understanding on user behavior of information diffusion, with the aim to reduce the spread of misinformation using Twitter during emergency situation.

Exploratory survey on an Evaluation Model for a Sense of Security

Research in information security is no longer limited to technical issues: human-related issues such as trust and the sense of security are also required by the user. In this paper, we use a Japanese word for such feelings, Anshin; “An” means to ease, and “Shin” is to mind. One feels Anshin when he is free from worry and fear. We try to identify the factors of Anshin so that we can construct a framework of the evaluation of Anshin. We present an initial Anshin model, and report our recent research results from user survey with factor analysis. We derive the following factors from the analysis; 1) user expectation of trust and confidence, 2) satisfaction with user interface and 3) understanding of risk and threats from user experience as well prior knowledge.

Towards an Interface causing Discomfort for Security: A User Survey on the Factors of Discomfort

It is necessary for users of computer systems to be aware of security threats. Our research is to implement an interface with which one would feel discomfort so that s/he would be aware of security risks. This paper reports our research on an explanatory factor analysis of discomfort feelings. As a result of the explanatory factor analysis, we present seven factors which contribute to discomfort feeling.

Trust Issues in Disaster Communications

The Great East Japan Earthquake on March 11th, 2011 caused severe damage to the northern coast of the main island in Japan. Since then we have been working to help out the affected area in terms of IT support such as internetworking and providing PCs. Through our support activities we came across an interesting issue concerning collaboration with people from heterogeneous backgrounds. We call this problem disaster communications in this paper. We found that trust plays an important role in such communications. In this paper we report our experiences during our support activities and our findings.

Usability issues in security

Usability issues in security have been discussed such that users could use the security tools easier. On contrary we presume another aspect of usability issues in security; an interface which causes a slight disturbance and discomfort so that a user would be aware of security threats and risks. The idea is that we should not feel Anshin to be secure. Anshin is a Japanese indicating the sense of security. We need a risk-aware interface to notice an insecure situation so that we would install security countermeasures. It is a warning interface for the insecure situations. We show how we could implement such an interface in a mail system to prevent users from sending email messages to incorrect destination addresses.

Implementation of an Internet Broadcasting System with Video Advertisement Insertion Based on Audience Comments

In recent years, mid-roll advertisements which insert a video advertisement at the middle of the video content appear gradually. However, the mid-roll advertisements usually interrupt video viewing because it inserts a video advertisement at the fixed or random time. To solve this issue, we propose an algorithm for mid-roll advertisement insertion based on audience comments. The algorithm determines timing for advertisement insertion not to interrupt audience’s video viewing as much as possible by detecting some characteristics in the amount of audience comments at the appropriate timing. In this paper, we conduct a preliminary experiment to invent an algorithm for video advertisement. We also implement a prototype system for video advertisement insertion with the proposed method.

A Proposal of an Interactive Broadcasting System for Audience-driven Live TV on the Internet

Traditional video services on the Internet are of a broadcasting service nature such as streaming and video-on-demand (VoD). Recent services incorporate more of the interactive nature of network applications such as easy video sharing and those with a chat function. Meanwhile, we have been conducting experimental Internet broadcasting in practice and found it difficult for non-professional broadcasters to provide audiences with satisfactory contents since they do not have a large budget or the technical knowledge to produce broadcasting contents compared to the professional ones. In this paper, we propose an audience-driven broadcast service model in which audiences can send their wish to a broadcaster such that they would like to see some specific objects while broadcasting; the broadcaster can reply back to the request as well. We implemented a prototype system for audience-driven live broadcasting and studied its effects and problems based on the results from the experimental broadcast at our university graduation ceremony and our campus festival. This paper reports our experiments and findings of the audience-driven live broadcasting.

Questionnaire Testing: Identifying Twitter User's Information Sharing Behavior during Disasters

The use of Twitter by citizens during catastrophic events is increasing with the availability of Internet services and the use of smartphones during disasters. After the Great East Japan Earthquake on 2011, Twitter was flooded with lots of disaster information, including misinformation that have been widely spread by retweet. Accordingly, we developed a questionnaire to investigate factors influenced people decision making to retweet disaster information they read from Twitter in disaster situations. We developed a questionnaire using brainstorming and KJ method and conducted a user survey (n = 57) to test the questionnaire items. Then, we analyzed using exploratory factor analysis and as a result, five factors derived from 38 question items which are: 1) Trustworthy information, 2) Relevance of the information during disasters, 3) Willingness to supply the information, 4) Importance of the information, and 5) Self Interest. However, there are 7 question items that need revision based on the results of the factor analysis. In this paper, we discuss the method we used to design the questionnaire and the result of the factor analyses of the questionnaire testing.

Issues in Disaster Communications

The Great East Japan Earthquake on March 11th, 2011 caused severe damage to the northern coast of the main island in Japan. Since then we have been working to help out the affected area in terms of IT support such as internetworking and providing PCs. Through our support activities we came across an interesting issue concerning collaboration with people from heterogeneous backgrounds. We call this problem disaster communications. In this paper we report our experiences during our support activities and our findings as well as some issues and our current work.