Agent-Based Delegation Model for the Secure Web Service in Ubiquitous Computing Environments

Web services are the new building block of today's Internet, and provides interoperability among heterogeneous distributed systems. Recently in web services environment, security has become one of the most critical issues. An attacker may expose user privacy and service information without authentication. Furthermore, in the ubiquitous computing environment, the users of web services must temporarily delegate some or all of their rights to agents in order to perform actions on their behalf. This results in the exposure of user privacy information by agents. We propose a delegation model for providing safety of web service and user privacy in ubiquitous computing environments. In order to provide safety of web service and user privacy, XML-based encryption and a digital signature mechanism needs to be efficiently integrated. In this paper, we propose web service management server based on XACML, in order to manage services and policies of web service providers. For this purpose, we extend SAML, in order to declare delegation assertions transferred to web service providers by delegation among agents.