Security and privacy are not only general requirements of a society but also indispensable enablers for innovative IT infrastructure applications aiming at increased, sustainable welfare and safety of a society. A critical activity of these IT applications is spontaneous information exchange. This information exchange, however, creates inevitable, unknown dependencies between the participating IT systems, which, in turn threaten security and privacy. With the current approach to IT security,

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... urity and privacy follow changes and incidents rather than anticipating them. By sticking to a given threat model, the current approach fails to consider vulnerabilities which arise during a spontaneous information exchange. With the goal of improving security and privacy, this work proposes adapting an IT security model and its enforcement to current and most probable incidents before they result in an unacceptable risk for the participating parties or failure of IT applications. Usage control is the suitable security policy model, since it allows changes during run-time without conceptually raising additional incidents.