In the present era of ubiquitous digitalization, security is a concern for everyone. Despite enormous efforts, securing IT systems still remains an open challenge for community and industry. One of the main reasons is that the variety and complexity of IT systems keeps increasing, making it practically impossible for security experts to grasp the full system. A further problem is that security has become an interdisciplinary challenge. While inter-disciplinary research does exist already, it is mostly restricted to collaborations between two individual disciplines and has been rather bottom-up by focusing on very specific problems.

The idea of the Dagstuhl Seminar is to go one step back and to follow a comprehensive top-down approach instead. The goal is to identify the "biggest failures" in security and to get a comprehensive understanding on their overall impact on security. To this end, the focus will be on the following questions:

• What are the main recurring reasons within disciplines why security solutions fail, i.e., the biggest failures? (Top View)
• How do these failures impact solutions that haven been developed in other sub-disciplines? (Broad View)
• What are possible strategies to solve these problems?

The Dagstuhl Seminar will be roughly divided into two parts. In the first half, experienced experts from different disciplines will give overview talks on the main problems of their field. Based on these, overlapping topics but also common research interests among the participants will be identified. The second half of the seminar is then reserved for discussions in individual working groups.