As the Web is increasingly used as a platform for heterogeneous applications, we are faced with new requirements to authentication, authorization and identity management. Modern architectures have to control access not only to single, isolated systems, but to whole business-spanning federations of applications and services. This task is complicated by the diversity of today’s specifications concerning e.g. privacy, system integrity and distribution in the web. The principal idea is to make use of Web service technology to separate authentication and authorization mechanisms from the applications themselves. In this context, the Security Assertion Markup Language (SAML) has been specified by OASIS as an XML-based notation for exchanging security-relevant information. The high number of different aspects like security technologies, cryptographic algorithms, and communication protocols entail a high degree of complexity. Id-me consist of reusable building blocks based on a simple, extendable model.