One of the specialties of HENSOLDT Cyber is *formal verification*. This may sound very sophisticated, but what is it exactly? In this blog, we will endeavor to explain. In general, whenever we write a computer program, we would like it to behave exactly the way we want it to. But how to be sure? Generally, the way software developers do this is by *testing*; running a program under specific circumstances and checking that it then does the right thing.