Effects of Architectural Decisions in Authentication and Authorisation Infrastructures

AAIs - infrastructures for authentication and authorisation provide services for service providers on the Internet. Especially if combined with an attribute infrastructure these AAIs can offer additional functionalities like a single sign-on, enhanced privacy, strengthened trust and security, or improved usability. In respect to security and privacy, the AAI acts as a mediator within the client service provider relationship, or, more likely, the client federation relation. Since an AAI is a loosely coupled combination of services architectural decisions influence its effects on privacy and security focusing either on customer demands or service provider requirements. This work shows how architecture and allocation decisions alone can shape the security and privacy contribution of AAIs leading to different levels of contentment for the user groups