We have learned that Math might be our last defence line against a real existing all-encompassing surveillance. One central challenge in this conflict is to combine authentication and anonymity. Number theory provides us many tools to create really surprising technologies for social communication. A lot of these technologies have not yet been brought to the world of concrete implementations. This has the implication that some ideas which have been presented years ago are not covered by patents any more. We have learned that Math might be our last defence line against a real existing all-encompassing surveillance. One central challenge in this conflict is to combine authentication and anonymity. Number theory provides us many tools to create really surprising technologies for social communication. A lot of these technologies have not yet been brought to the world of concrete implementations. This has the implication that some ideas which have been presented years ago are not covered by patents any more.