Biblio

Federated Identity Management (FIM) is a model of identity management in which different trusted organizations can provide secure online services to their uses. Security Assertion Markup Language (SAML) is one of the widely-used technologies for FIM. However, a SAML-based FIM has two significant issues: the metadata (a crucial component in SAML) has security issues, and federation management is hard to scale. The concept of dynamic identity federation has been introduced, enabling previously unknown entities to join in a new federation facilitating inter-organization service provisioning to address federation management's scalability issue. However, the existing dynamic federation approaches have security issues concerning confidentiality, integrity, authenticity, and transparency. In this paper, we present the idea of facilitating dynamic identity federations utilizing blockchain technology to improve the existing approaches' security issues. We demonstrate its architecture based on a rigorous threat model and requirement analysis. We also discuss its implementation details, current protocol flows and analyze its performance to underline its applicability.

Perimeter models, which provide access control for protecting resources on networks, make authorization decisions using the source network of access requests as one of critical factors. However, such models are problematic because once a network is intruded, the attacker gains access to all of its resources. To overcome the above problem, a Zero Trust Network (ZTN) is proposed as a new security model in which access control is performed by authenticating users who request access and then authorizing such requests using various information about users and devices called contexts. To correctly make authorization decisions, this model must take a large amount of various contexts into account. However, in some cases, an access control mechanism cannot collect enough context to make decisions, e.g., when an organization that enforces access control joins the identity federation and uses systems operated by other organizations. This is because the contexts collected using the systems are stored in individual systems and no federation exists for sharing contexts. In this study, we propose the concept of a Zero Trust Federation (ZTF), which applies the concept of ZTN under the identity federation, and a method for sharing context among systems of organizations. Since context is sensitive to user privacy, we also propose a mechanism for sharing contexts under user control. We also verify context sharing by implementing a ZTF prototype.

Identity Management systems cannot be centralized anymore. Nowadays, users have multiple accounts, profiles and personal data distributed throughout the web and hosted by different providers. However, the online world is currently divided into identity silos forcing users to deal with repetitive authentication and registration processes and hindering a faster development of large scale e-business. Federation has been proposed as a technology to bridge different trust domains, allowing user identity information to be shared in order to improve usability. But further research is required to shift from the current static model, where manual bilateral agreements must be pre-configured to enable cooperation between unknown parties, to a more dynamic one, where trust relationships are established on demand in a fully automated fashion. This paper presents IdMRep, the first completely decentralized reputation-based mechanism which makes dynamic federation a reality. Initial experiments demonstrate its accuracy as well as an assumable overhead in scenarios with and without malicious nodes.