ÆTHER: an Authorization Management Architecture for Ubiquitous Computing

Abstract. The ubiquitous computing paradigm suggests that we are going to be surrounded by countless wireless devices capable of providing services trans-parently. By definition, the nature of ubiquitous computing environments is open and extremely dynamic, making difficult the establishment of predefined security relationships between all of the participating entities. Authentication mechanisms can be employed to establish the identity of a pervasive computing entity but they suffer from scalability problems and have limited value in defin-ing authorization decisions among strangers. In this paper we propose ÆTHER, an authorization management architecture designed specifically to address trust establishment and access control in ubiquitous computing environments. Own-ers define attribute authority sets and access control policy entries that are em-bedded into their devices. Members of the attribute authority sets are trusted to issue credentials for the corresponding attributes that can then be used in order to gain access to protected resources. Our architecture supports dynamic mem-bership in these sets facilitating distributed administration, which is required in the context of the volatile nature of ubiquitous security relationships, and at-tribute mapping to allow roaming among authority domains. Moreover, we pre-sent the foundation of a logic model for our proposed architecture that is used to prove access control decisions.