Towards Trust for Semantic Web Annotations

1. INTRODUCTION In the Semantic Web, users can attach (semantic) meta data to Web resources. One problem is the trustworthiness of these annotations. This paper identifies two main steps towards a Semantic Web trust framework and provides possible solutions. In the Semantic Web, users can attach (semantic) meta data to Web resources. These annotations can then be displayed to other users or used by computer programs to improve the understanding of content. For example, in an E-Learning scenario, users could annotate (Web) resources with meta data such as " difficult " or " important " , or rate resources with regard to a certain topic or course. The first step is to authenticate users and annotations. This is done in our approach by introducing Liberty Alliance identity management into Semantic Web annotations. Users have to login using Liberty Alliance accounts to create or modify annotations and their credentials are stored with the annotations. The author of an annotation can also define optional access rights to her annotations, for example to restrict access to the participants of a lecture course. We present our implementation which is an extension of the Annozilla plugin for the Mozilla Web browser. One advantage of using the Liberty Alliance specification for authentication is possible interoperability with other Web applications. Users can thereby reuse accounts for different services under their control (identity management). One problem is the trustworthiness of annotations. In the traditional WWW, users have to manually decide whether a Web page is trustworthy or not. For example, an annotation by the lecturer of a course would constitute high trust to her students. In a Semantic Web, we need a framework for representing trust in Web resources which can be used by programs to enhance search results or information personalization, for example. Annotea provides a standardized framework for the creation and management of annotations [1]. Usually, Web server functionality provides user authentication for annotations. Often, the standard HTTP authentication mechanism is used. In this case, users have to provide credentials to access annotations but the identity information is not associated with the annotation itself. Existing approaches for secure authentication in open networks, such as the Liberty Alliance project, are not integrated into annotation infrastructures. The second step is a framework for expressing trust in a (Web) resource. Users can rate resources (or other trust ratings) using a trust ontology. The rating is always done with regard …