  Not a day goes by without news about a cyber attack. Fear spreads out and
lots of wrong ideas circulate. This survey aims at showing how all these
uncertainties about cyber can be transformed into manageable risk. After
reviewing the main characteristics of cyber risk, we consider the three layers
of cyber space: hardware, software and psycho-cognitive layer. We ask ourselves
how is this risk different from others, how modelling has been tackled and
needs to evolve, and what are the multi-facetted aspects of cyber risk
management. This wide exploration pictures a science in the making and points
out the questions to be solved for building a resilient society.
