If we have learned one thing during the past decade, it is that cyber security is a complex affair. During this decade, we have seen many things go wrong in the digital domain. These incidents have left us much more experienced, but also a little confused. Where do we go from here? In this International Trend Report, three European national CERTs (Computer Emergency Response Teams) share some of their experiences of recent years by means of three case studies. The central theme for all cases is ‘Trust’: the need for it, and possibly the lack of it in the digital world. The Swedish national CERT, MSB, has contributed a case involving an availability disruption at IT operations provider Tieto. BSI, the German national CERT, describes the events during a DoS amplification attack on a major telecommunications provider in Germany. The contribution of the NCSC, the national CERT of the Netherlands, is a case on the DigiNotar crisis, which also had farreaching international repercussions.