Trust by design -- in praise of modularization: a case study

Ensuring that collective adaptive systems remain safe, reliable, and trustworthy requires measures that transcend so far established formal methods, and in particular established verification techniques. In this contribution, we suggest three such measures: (1) conceptual means: runs with locally confined cause and effect of events, (2) temporal logic like verification techniques that respect and exploit such runs, (3) composing system properties from properties of components. This contribution presents a case study which particularly focuses on the benefits of modularization for achieving trust by design. Further work will develop a full-fledged theory for the presented ideas.