The concepts of trust and security are deeply embedded in our society and are therefore strongly affected by the societal transformation caused by the digitisation. Societal and technical change is strongly influenced by the growing complexity of society related to the emergence of easy worldwide communication, the Web and mass data collection. In this paper I discuss security and trust as fundamental drivers for self-organisation in our society. I highlight the concepts of trustworthy technology and trust in the societal context, as well as the difference between accepting technology and trusting technology. An important observation is that a complex system cannot be fully understood by reductionism alone. The discussion leads to some cautious conclusions on future actions.