@inproceedings{CamGroSo_2006,
        title = {User Centricity: A Taxonomy and Open Issues},
        address = {New York, NY, USA},
        author = {Abhilasha Bhargav-Spantzel and Jan Camenisch and Thomas Gross and Dieter Sommer},
        booktitle = {DIM '06: Proceedings of the second ACM workshop on Digital identity management},
        pages = {1-10},
        publisher = {ACM},
        year = 2006,
        url = {http://portal.acm.org/citation.cfm?id=1179529.1179531},
        location = {Alexandria, Virginia, USA},
	isbn = {1-59593-547-9},
	doi = {http://doi.acm.org/10.1145/1179529.1179531},
	abstract = {User centricity is a significant concept in federated identity management (FIM), as it provides for stronger user control and privacy. However, several notions of user-centricity in the FIM community render its semantics unclear and hamper future research in this area. Therefore, we consider user-centricity abstractly and establish a comprehensive taxonomy encompassing user-control, architecture, and usability aspects of user-centric FIM. On the systems layer, we discuss user-centric FIM systems and classify them into two predominant variants with significant feature sets. We distinguish credential-focused systems, which advocate offline identity providers and long-term credentials at a user's client, and relationship-focused systems, which rely on the relationships between users and online identity providers that create short-term credentials during transactions. Note that these two notions of credentials are quite different. The further one encompasses cryptographic credentials as defined by Lysyanskaya et al. [30], the latter one federation tokens as used in today's FIM protocols like Liberty.We raise the question where user-centric FIM systems may go--within the limitations of the user-centricity paradigm as well as beyond them. Firstly, we investigate the existence of a universal user-centric FIM system that can achieve a superset of security and privacy properties as well as the characteristic features of both pre-dominant classes. Secondly, we explore the feasibility of reaching beyond user-centricity, that is, allowing a user of a user-centric FIM system to again give away user-control by means of an explicit act of delegation. We do neither claim a solution for universal user-centric systems nor for the extension beyond the boundaries ventures by leveraging the properties of a credential-focused FIM system.},
	biburl = {http://www.bibsonomy.org/bibtex/23a17b08f3a1d86ee64ecf78394cd7802/dawinci},
	keywords = {delegation user_centric privacy taxonomy security user_centriciy identity_management}
}