  Identity Management is becoming more and more important in business systems
as they are opened for third parties including trading partners, consumers and
suppliers. This paper presents an approach securing a system without any
knowledge of the system source code. The security module adds to the existing
system authentication and authorisation based on aspect oriented programming
and the liberty alliance framework, an upcoming industrie standard providing
single sign on. In an initial training phase the module is adapted to the
application which is to be secured. Moreover the use of hardware tokens and
proactive computing is demonstrated. The high modularisation is achived through
use of AspectJ, a programming language extension of Java.
