Takaaki Komura

Community viewer: visualizing community formation on personal digital assistants

Mobile computing has been mainly utilized for point-to-point communication services, such as E-mail or FAX among people. To advance this field, the challenge is to encourage group communication by providing information that encourages community formation. As the first step towards this goal, we experimentally implemented the community viewer, which dynamically visualizes the communication interaction among people in the community. To design the community viewer, we introduced (1) the party room metaphor, which provides a virtual place for representing various community activities, and (2) the reflector icon, which reflects the activity of the corresponding individual while protecting his/her privacy. The static relationship among people and their dynamic activities are displayed in the spatial arrangement of reflector icons in the party room. We report our experiments on implementing and testing the community viewer in an international conference using 100 personal digital assistants.

Implementation of AV Streaming System Using Peer-to-Peer Communication

In this paper, a prototype implementation of stream- ing system that allows listening to and viewing multimedia contents using a mobile terminal, as part of our efforts toward realizing services linked with home networks and mobile net- works is presented. In our system, appliances are detected and connected to a mobile terminal by use of peer-to-peer (P2P) network based on the PUCC protocols, and they are controlled by use of P2P messages and IEEE1394 AV/C. Streaming is managed by a gateway on the P2P network, where multimedia contents are converted to another format suitable to be sent to mobile terminals. This prototype system successfully achieves video data streaming over two different networks by using P2P network which conceals the differences among the networks.

Design and Implementation of Web Forward Proxy with Shibboleth Authentication

We propose a web forward proxy server with authentication method using Shibboleth. With this proxy Single Sign-On would benefit a user and also authentication using Shibboleth protocol solves problems in basic access authentication and digest access authentication supported by existing web forward proxy servers. In order to realize it, the proxy needs to recognize attributes of shibboleth protocol and session cookies and to modify session cookies. We implemented system and evaluated it by accessing to electronic journals from a test network.

Loosely Trusted Yet Secure Roaming Architecture for Public Wireless Internet Service

The demand of providing ones network bandwidth for another such as a business partner or a guest in a form like a so-called free wireless Internet access is rising. However, in some countries like Japan, the law concerning the responsibility of Internet service providers requires not only ISPs who operate roaming service but also anyone who provide access to the Internet to identify an illicit user when requested. Otherwise he himself may be treated as the illicit user. In this paper, we first categorize conventional roaming models and consider trust relationships in roaming. Conventional roaming models assume trust between a connectivity provider and an authenticator. Most measures are against abuse of a mobile user or a fake user as an attacker. Based on the consideration, we propose an autonomous distributed model account management architecture. With this architecture, when an illicit use occurs, every concerned party can find who do it even in the case that not only a mobile user but also a connectivity provider and/or an authenticator may do it. This is possible if a connectivity provider allows only traffics of some well known secure authentication protocols and user data which are authenticated with them to go through his network. This proposal makes it possible for a connectivity provider to provide access for a mobile user securely as easy as a free wireless access without trust with any authenticator

An Authentication Federation Proxy Which Conceals Attributes and Authorization Policies Each Other

A mechanism for privacy-enhanced authentication and authorization federation is proposed. The mechanism conceals attributes of a user provided by the IdP from the SP, and simultaneously conceals an authorization policy of a service presented by the SP from the IdP. The mechanism is implemented as an authentication federation proxy which works between an IdP and an SP. Attributes of a user is provided to the proxy by the IdP and an authorization policy is presented to the proxy by the SP, but both of the attributes and the authorization policy are scrambled. The proxy can determine whether the given attributes match the policy but it can neither know the detail of attributes nor the policy.